3
Mathematics for the Fluid Earth
http://sms.cam.ac.uk/collection/1580157
The purpose of this programme is to bring together scientists from very different perspectives in models of the dynamics of the fluid components of the Earth system. This interest may be directly into the modelling, also numerical, or at a more abstract modelling level in terms of understanding the climate system as a complex dynamical system. This programme aims to prove that there is a close connection between “core” questions and problems of pure and applied mathematics and “core” questions of geophysical fluid dynamics relevant for the investigation of the climate system and of its component, and that these are closely linked to defining rigorously what is a good model for a complex system. The aim of the programme is to provide a common ground for fostering mutually stimulating and inspiring exchanges and for creating opportunities for future research.
Read more at http://www.newton.ac.uk/programmes/MFE/
1440
2014
Mon, 24 Mar 2014 16:46:29 +0000
Fri, 18 Oct 2013 14:31:39 +0100
en
smssupport@uis.cam.ac.uk
Mathematics for the Fluid Earth
http://sms.cam.ac.uk/collection/1580157
http://rss.sms.cam.ac.uk/itunesimage/1580158.jpg
http://video.search.yahoo.com/mrss
Mathematics for the Fluid Earth
The purpose of this programme is to bring together scientists from very different perspectives in models of the dynamics of the fluid components of the Earth system. This interest may be directly into the modelling, also numerical, or at a more abstract modelling level in terms of understanding the climate system as a complex dynamical system. This programme aims to prove that there is a close connection between “core” questions and problems of pure and applied mathematics and “core” questions of geophysical fluid dynamics relevant for the investigation of the climate system and of its component, and that these are closely linked to defining rigorously what is a good model for a complex system. The aim of the programme is to provide a common ground for fostering mutually stimulating and inspiring exchanges and for creating opportunities for future research.
Read more at http://www.newton.ac.uk/programmes/MFE/
Mathematics for the Fluid Earth
The purpose of this programme is to bring together scientists from very different perspectives in models of the dynamics of the fluid components of the Earth system. This interest may be directly into the modelling, also numerical, or at a more abstract modelling level in terms of understanding the climate system as a complex dynamical system. This programme aims to prove that there is a close connection between “core” questions and problems of pure and applied mathematics and “core” questions of geophysical fluid dynamics relevant for the investigation of the climate system and of its component, and that these are closely linked to defining rigorously what is a good model for a complex system. The aim of the programme is to provide a common ground for fostering mutually stimulating and inspiring exchanges and for creating opportunities for future research.
Read more at http://www.newton.ac.uk/programmes/MFE/
Cambridge University
Sarah Middle
sm828@cam.ac.uk
http://sms.cam.ac.uk/collection/1580157
Mathematics for the Fluid Earth
20131018T14:31:39+01:00
INIMS
101092
no

A largedeviation approach to passive scalar advection, diffusion and reaction
ucs_sms_1580157_1589196
http://sms.cam.ac.uk/media/1589196
A largedeviation approach to passive scalar advection, diffusion and reaction
Vanneste, J (University of Edinburgh)
Wednesday 30 October 2013, 15:5516:30
Thu, 31 Oct 2013 13:07:57 +0000
108
108100
Isaac Newton Institute
Vanneste, J
0489b03fe380fb509b791c119921df15
1236aa60cd03dd7ec7c7fff303c61201
4a6947aab05c62da3361c2a683b22989
70c2a57bc442f708a2afd0a846ad02b6
Vanneste, J (University of Edinburgh)
Wednesday 30 October 2013, 15:5516:30
Vanneste, J (University of Edinburgh)
Wednesday 30 October 2013, 15:5516:30
Cambridge University
2391
http://sms.cam.ac.uk/media/1589196
A largedeviation approach to passive scalar advection, diffusion and reaction
Vanneste, J (University of Edinburgh)
Wednesday 30 October 2013, 15:5516:30
Coauthors: Peter H. Haynes (University of Cambridge), Alexandra Tzella (University of Birmingham)
The dispersion of a passive scalar in a fluid through the combined action of advection and molecular diffusion can often be described as a diffusive process, with an effective diffusivity that is enhanced compared to the molecular value. This description fails to capture the tails of the scalar concentration in initialvalue problems, however. This talk addresses this issue and shows how the theory of large deviation can be applied to capture the concentration tails by solving a family of eigenvalue problems. Two types of flows are considered: shear flows and cellular flows. In both cases, large deviation is shown to generalise classical results (Taylor dispersion for shear flows, homogenisation results for cellular flows). Explicit asymptotic results are obtained in the limit of large Péclet number corresponding to small molecular diffusivity. The implications of the results for the problem of front propagation in reacting flows are also discussed.
20140324T16:46:29+00:00
2391
1589196
true
16x9
false
no

A new recurrences based technique for detecting robust extrema in long temperature records
ucs_sms_1580157_1588462
http://sms.cam.ac.uk/media/1588462
A new recurrences based technique for detecting robust extrema in long temperature records
Faranda, D (CEA/Saclay)
Tuesday 29 October 2013, 14:5015:25
Wed, 30 Oct 2013 12:43:49 +0000
108
Isaac Newton Institute
Faranda, D
9beaa01e61fc17ed5d93b1d2c948c32a
1b46ec79e5153092f5f262f066f2d077
efc939296ae386585d07c49942fb7466
588a4dd571665765ccfb4f037fa4c8b9
Faranda, D (CEA/Saclay)
Tuesday 29 October 2013, 14:5015:25
Faranda, D (CEA/Saclay)
Tuesday 29 October 2013, 14:5015:25
Cambridge University
2095
http://sms.cam.ac.uk/media/1588462
A new recurrences based technique for detecting robust extrema in long temperature records
Faranda, D (CEA/Saclay)
Tuesday 29 October 2013, 14:5015:25
Coauthor: Sandro Vaienti (University of Marseille)
By using new techniques originally developed for the analysis of extreme values of dynamical systems, several long records of temperatures at different locations are analysed by showing that they have the same recurrence time statistics of a chaotic dynamical system perturbed with dynamical noise and by instrument errors. The technique provides a criterion to discriminate whether the recurrence of a certain temperature belongs to the natural climate variability or can be considered as a real extreme event with respect to a specific time scale fixed as parameter. The method gives a selfconsistent estimation of the convergence.
20140317T14:33:14+00:00
2095
1588462
true
16x9
false
no

Adaptive stochastic trajectory modelling of transport in geophysical flows
ucs_sms_1580157_1610860
http://sms.cam.ac.uk/media/1610860
Adaptive stochastic trajectory modelling of transport in geophysical flows
Esler, JG (University College London)
Tuesday 03 December 2013, 14:0014:45
Fri, 06 Dec 2013 16:36:50 +0000
Isaac Newton Institute
Esler, JG
c6ecef44a737e692168b5cd7fb912e95
f591c0854f17c89d83052a887728f930
237474d89699161bd09c062a53c9ebb9
9680e7b394655b81a79bc53c3d940dc5
Esler, JG (University College London)
Tuesday 03 December 2013, 14:0014:45
Esler, JG (University College London)
Tuesday 03 December 2013, 14:0014:45
Cambridge University
2049
http://sms.cam.ac.uk/media/1610860
Adaptive stochastic trajectory modelling of transport in geophysical flows
Esler, JG (University College London)
Tuesday 03 December 2013, 14:0014:45
Motivated by the goal of improving and augmenting stochastic Lagrangian models of particle dispersion in turbulent geophysical flows, techniques from the theory of stochastic processes are applied to a model transport problem. The aim is to find an efficient and accurate method to calculate the total tracer transport between a source and a receptor when the flow between the two locations is weak, rendering direct stochastic Lagrangian simulation prohibitively expensive. Two methods are found to be useful. The first is Milstein's `measure transformation method', which involves adding an artificial velocity to the trajectory equation, and simultaneously correcting for the weighting given to each particle under the new flow. Various difficulties associated with making an appropriate choice for the artificial velocity field are detailed and addressed. The second method is a variant of Grassberger's `gowiththewinners' branching process, which acts to remove particles unlikely to contribute to the net transport, and reproduces those that will contribute. A simple solution to the problem of defining a `winner' for flows in a high Peclet number chaotic advection regime is proposed. It is demonstrated that, used independently or together, the two methods can act to reduce the variance of estimators of the total transport by several orders of magnitude compared with direct simulation.
20131206T16:36:51+00:00
2049
1610860
true
16x9
false
no

Anomalous fluctuation relations
ucs_sms_1580157_1589189
http://sms.cam.ac.uk/media/1589189
Anomalous fluctuation relations
Klages, R (Queen Mary, University of London)
Wednesday 30 October 2013, 14:5015:25
Thu, 31 Oct 2013 12:51:27 +0000
Isaac Newton Institute
Klages, R
067d415b5ed71c63077e59f06ecb1bf0
05d0fc3c1feae0fc5b3c3bc835d51a80
09a60c8e38020c86705c33f3afae1b20
d188204483e9b1b6f5e260cdac7ae9b4
Klages, R (Queen Mary, University of London)
Wednesday 30 October 2013,...
Klages, R (Queen Mary, University of London)
Wednesday 30 October 2013, 14:5015:25
Cambridge University
1810
http://sms.cam.ac.uk/media/1589189
Anomalous fluctuation relations
Klages, R (Queen Mary, University of London)
Wednesday 30 October 2013, 14:5015:25
Coauthors: Aleksei V. Chechkin (Institute for Theoretical Physics NSC KIPT, Kharkov, Ukraine), Peter Dieterich (Institut fuer Physiologie, Medizinische Fakultaet Carl Gustav Carus, Dresden, Germany), Friedrich Lenz (Queen Mary University of London, School of Mathematical Sciences, London, UK)
We study Fluctuation Relations (FRs) for Gaussian stochastic systems that are anomalous, in the sense that the diffusive properties strongly deviate from the ones of Brownian motion. For this purpose we use a Langevin approach: We first briefly review the concept of transient work FRs for simple Langevin dynamics generating normal diffusion [1]. We then consider two different types of additive, power law correlated Gaussian noise [2,3]: (1) internal noise with a fluctuationdissipation relation of the second type (FDR2), and (2) external noise without FDR2. For internal noise we find that FDR2 leads to conventional (normal) forms of transient work FRs. For external noise we obtain various forms of violations of normal FRs, which we call anomalous FRs. We show that our theory is important for understanding experimental results on fluctuations in systems with longtime correlations, such as glassy dynamics [1].
[1] R.Klages, A.V.Chechkin, P.Dieterich, Anomalous fluctuation relations, book chapter in: R.Klages, W.Just, C.Jarzynski (Eds.), Nonequilibrium Statistical Physics of Small Systems, WileyVCH, Weinheim (2013) [2] A.V.Chechkin, F.Lenz, R.Klages, J.Stat.Mech. L11001 (2012) [3] A.V.Chechkin, R.Klages, J.Stat.Mech. L03002 (2009)
20131031T12:51:59+00:00
1810
1589189
true
16x9
false
no

Asymmetric inertial instability
ucs_sms_1580157_1674137
http://sms.cam.ac.uk/media/1674137
Asymmetric inertial instability
Zeitlin, V (Laboratoire de Météorologie Dynamique (LMDENS))
Wednesday 11 December 2013, 11:0012:00
Mon, 17 Mar 2014 14:01:46 +0000
108
Isaac Newton Institute
Zeitlin, V
fe010756cc7009b17514b3046253c77b
ed27b1d291aa5c3e724086581902835e
453d22550663af89e704d9d87799e89e
e0e95350b215d0d8a5add2acfdedf96b
Zeitlin, V (Laboratoire de Météorologie Dynamique (LMDENS))
Wednesday 11...
Zeitlin, V (Laboratoire de Météorologie Dynamique (LMDENS))
Wednesday 11 December 2013, 11:0012:00
Cambridge University
4140
http://sms.cam.ac.uk/media/1674137
Asymmetric inertial instability
Zeitlin, V (Laboratoire de Météorologie Dynamique (LMDENS))
Wednesday 11 December 2013, 11:0012:00
20140317T14:32:51+00:00
4140
1674137
true
16x9
false
no

Balance relations for rotating fluid flow
ucs_sms_1580157_1613251
http://sms.cam.ac.uk/media/1613251
Balance relations for rotating fluid flow
Oliver, M (Jacobs University Bremen)
Thursday 05 December 2013, 14:0014:45
Tue, 10 Dec 2013 09:39:19 +0000
Isaac Newton Institute
Oliver, M
0338c5143320c946125ae366feba024e
0e2b4868e02e08cd423205283f1a986f
5f8e8f8aeeb109a23f90cb46dd778c25
9a109d996446dc67f3ac3ea48146e6b9
Oliver, M (Jacobs University Bremen)
Thursday 05 December 2013, 14:0014:45
Oliver, M (Jacobs University Bremen)
Thursday 05 December 2013, 14:0014:45
Cambridge University
2711
http://sms.cam.ac.uk/media/1613251
Balance relations for rotating fluid flow
Oliver, M (Jacobs University Bremen)
Thursday 05 December 2013, 14:0014:45
We discuss different nonlinear elliptic balance relations for rotating shallow water flow and describe computational tests which compare their utility as an initialization or diagnostic tool in nearly geostrophic situations.
20131210T09:39:19+00:00
2711
1613251
true
16x9
false
no

Bayesian approaches for wind gust and quantitative precipitation forecasting
ucs_sms_1580157_1591228
http://sms.cam.ac.uk/media/1591228
Bayesian approaches for wind gust and quantitative precipitation forecasting
Friederichs, P (Universität Bonn)
Thursday 31 October 2013, 14:1514:50
Mon, 04 Nov 2013 09:56:24 +0000
Isaac Newton Institute
Friederichs, P
3811522bb1ebd251e6014392d5b31627
f80582dc48e930894e3dabc59ce3b5f4
f0b50d6f1791d4aedce224dba3ebfebf
6e6c11054a722416b3f2ba15a11b83c8
Friederichs, P (Universität Bonn)
Thursday 31 October 2013, 14:1514:50
Friederichs, P (Universität Bonn)
Thursday 31 October 2013, 14:1514:50
Cambridge University
1647
http://sms.cam.ac.uk/media/1591228
Bayesian approaches for wind gust and quantitative precipitation forecasting
Friederichs, P (Universität Bonn)
Thursday 31 October 2013, 14:1514:50
Coauthor: Sabrina Bentzien (Meteorological Institute, University of Bonn, Germany)
Due to large uncertainties, predictions of highimpact weather on the atmospheric mesoscale are probabilistic in nature. Mesoscale weather ensemble prediction systems (EPS) are developed to obtain probabilistic guidance for high impact weather. An EPS not only issues a deterministic future state of the atmosphere but a sample of possible future states. Ensemble postprocessing then translates such a sample of forecasts into probabilistic measures.
We discuss Bayesian approaches for wind gust and quantitative precipitation forecasting. The Bayesian hierarchical model (BHM) for wind gusts uses extreme value theory, namely a generalized extreme value distribution (GEV), in the data level. A process level for the parameters is introduced which, on the one hand, models the spatial response surfaces of the GEV parameters as Gaussian random fields, and, on the other hand, incorporate the information of the COSMODE forecasts. The spatial BHM provides area wide forecasts of wind gusts in terms of a conditional GEV. It models the marginal distribution of the spatial gust process and provides not only forecasts of the conditional GEV at locations without observations, but also uncertainty information about the estimates. At this stage, the BHM ignores the conditional dependence between gusts at neighboring locations. However, an outline is given how this will be incorporated in a subsequent study using maxstable random fields.
For quantitative precipitation forecasting we use Bayesian quantile regression and its spatially adaptive extension together with a variable selection based on a Bayesian LASSO. All this is illustrated for the Germanfocused mesoscale weather prediction ensemble COSMODEEPS, which runs operationally since December 2010 at the German Meteorological Service (DWD). We further discuss the issue of objective outofsample verification, where performance is measured using proper scoring rules and their decomposition.
20131104T09:58:15+00:00
1647
1591228
true
16x9
false
no

Between quasigeostrophic and stratified turbulence
ucs_sms_1580157_1609070
http://sms.cam.ac.uk/media/1609070
Between quasigeostrophic and stratified turbulence
Bartello, P (McGill University)
Monday 02 December 2013, 14:0014:45
Tue, 03 Dec 2013 14:08:39 +0000
Isaac Newton Institute
Bartello, P
84611b45aa969aea13b5b211c117ba4a
7ca67ff44a2f12df58bd8576844b8265
5b2f25e85acbdab98e3a16e9a9b7005b
86cc7757e285d3046d43990f0d37132e
Bartello, P (McGill University)
Monday 02 December 2013, 14:0014:45
Bartello, P (McGill University)
Monday 02 December 2013, 14:0014:45
Cambridge University
2664
http://sms.cam.ac.uk/media/1609070
Between quasigeostrophic and stratified turbulence
Bartello, P (McGill University)
Monday 02 December 2013, 14:0014:45
While it is wellestablished that the frequency disparity between vortical and wave motion is key to understanding the quasigeostrophic limit, i.e. strong rotation and stratification, the starting point for this contribution is that it has recently been established that there is no such frequency disparity in stratified turbulence without rotation. It remains to ask what happens in between these two limits, long held as the prevailing dynamics between deformationscale eddies and the microscale where isotropy is recovered. To do this, ideas from numerical weather prediction were borrowed in order to explore numerically the nonhydrostatic Boussinesq equations starting from initial conditions that are close to our current fuzzy notions of balance for a variety of Rossby and Froude numbers. It is found that evolution is immediately away from this balance in the small scales, and from steep to much more shallow spectra. It will be argued that this conclusion is robust to unce rtainties in the definition of balance.
20131203T14:08:39+00:00
2664
1609070
true
16x9
false
no

Breakdown of linear response in the presence of bifurcations
ucs_sms_1580157_1598470
http://sms.cam.ac.uk/media/1598470
Breakdown of linear response in the presence of bifurcations
Baladi, V (CNRS and Ecole Normale Supérieure, Paris)
Tuesday 12 November 2013, 10:0011:00
Thu, 14 Nov 2013 15:28:06 +0000
Isaac Newton Institute
Baladi, V
dbdd8e5a2a9758eb16382d6ee6993e70
02eda922d7c92d2d7b6677423d92cce1
9b4c6822d967eb539346fb30f7656cf3
cde07a79220039046889511b8fde6c8d
Baladi, V (CNRS and Ecole Normale Supérieure, Paris)
Tuesday 12 November 2013,...
Baladi, V (CNRS and Ecole Normale Supérieure, Paris)
Tuesday 12 November 2013, 10:0011:00
Cambridge University
3580
http://sms.cam.ac.uk/media/1598470
Breakdown of linear response in the presence of bifurcations
Baladi, V (CNRS and Ecole Normale Supérieure, Paris)
Tuesday 12 November 2013, 10:0011:00
(Joint with: M. Benedicks and D. Schnellmann) Many interesting dynamical systems possess a unique SRB ("physical") measure, which behaves well with respect to Lebesgue measure. Given a smooth oneparameter family of dynamical systems f_t, is natural to ask whether the SRB measure depends smoothly on the parameter t. If the f_t are smooth hyperbolic diffeomorphisms (which are structurally stable), the SRB measure depends differentiably on the parameter t, and its derivative is given by a "linear response" formula (Ruelle, 1997). When bifurcations are present and structural stability does not hold, linear response may break down. This was first observed for piecewise expanding interval maps, where linear response holds for tangential families, but where a modulus of continuity t log t may be attained for transversal families (BaladiSmania, 2008). The case of smooth unimodal maps is much more delicate. Ruelle (Misiurewicz case, 2009) and BaladiSmania (slow recurrence case, 2012) obtained linear response for fully tangential families (confined within a topological class). The talk will be nontechnical and most of it will be devoted to motivation and history. We also aim to present our new results on the transversal smooth unimodal case (including the quadratic family), where we obtain Holder upper and lower bounds (in the sense of Whitney, along suitable classes of parameters).
20131114T15:28:06+00:00
3580
1598470
true
16x9
false
no

Change of phase for the humid atmosphere
ucs_sms_1580157_1610853
http://sms.cam.ac.uk/media/1610853
Change of phase for the humid atmosphere
Temam, RM (Indiana University)
Tuesday 03 December 2013, 10:1511:00
Fri, 06 Dec 2013 16:41:05 +0000
Isaac Newton Institute
Temam, RM
0fd9be90452e711d07fb969031c84284
85c81f9e92024876105eeeff802f4269
4f0c26761ccb5db8cad2eee4185d69a6
70e3150d75b986c2a5100f4bc58ab992
Temam, RM (Indiana University)
Tuesday 03 December 2013, 10:1511:00
Temam, RM (Indiana University)
Tuesday 03 December 2013, 10:1511:00
Cambridge University
2870
http://sms.cam.ac.uk/media/1610853
Change of phase for the humid atmosphere
Temam, RM (Indiana University)
Tuesday 03 December 2013, 10:1511:00
In this lecture we will recall the atmospheric equations of water vapor with saturation. In their simplest form, these equations form a nonlinear system of partial differential equations with discontinuities. We will address the issue of the modelling of the system in the presence of singularities, and some questions on the existence, uniqueness and regularity of these solutions.
20131206T16:41:05+00:00
2870
1610853
true
16x9
false
no

Coarse Graining and Entropy Production in a General Circulation Model
ucs_sms_1580157_1603038
http://sms.cam.ac.uk/media/1603038
Coarse Graining and Entropy Production in a General Circulation Model
Lucarini, V (Universität Hamburg)
Wednesday 20 November 2013, 11:0012:00
Fri, 22 Nov 2013 14:18:28 +0000
Isaac Newton Institute
Lucarini, V
54f80804a170c4ce1fcedd391bd5251e
0d57043ee32c6c8ac1471d980c6dabc3
579138947bbd747881a934b0f7c8dad1
ddb7876d95defaff4f36d259581eb8a8
Lucarini, V (Universität Hamburg)
Wednesday 20 November 2013, 11:0012:00
Lucarini, V (Universität Hamburg)
Wednesday 20 November 2013, 11:0012:00
Cambridge University
3209
http://sms.cam.ac.uk/media/1603038
Coarse Graining and Entropy Production in a General Circulation Model
Lucarini, V (Universität Hamburg)
Wednesday 20 November 2013, 11:0012:00
20131122T14:18:28+00:00
3209
1603038
true
16x9
false
no

Complex networks identify spatial patterns of extreme rainfall events of the Indian and the South American monsoon system
ucs_sms_1580157_1591249
http://sms.cam.ac.uk/media/1591249
Complex networks identify spatial patterns of extreme rainfall events of the Indian and the South American monsoon system
Kurths, J (Potsdam Institute for Climate Impact Research (PIK))
Thursday 31 October 2013, 16:2517:00
Mon, 04 Nov 2013 10:20:27 +0000
Isaac Newton Institute
Kurths, J
5a01c528109c97215b8663efc1dea755
e872a0f1880bf25567d27a466a874b03
e2c04e74b417f2f9def0cf2c679be1e6
9f9e2fa34c5e1523625b7fbcc5d338ea
Kurths, J (Potsdam Institute for Climate Impact Research (PIK))
Thursday 31...
Kurths, J (Potsdam Institute for Climate Impact Research (PIK))
Thursday 31 October 2013, 16:2517:00
Cambridge University
1987
http://sms.cam.ac.uk/media/1591249
Complex networks identify spatial patterns of extreme rainfall events of the Indian and the South American monsoon system
Kurths, J (Potsdam Institute for Climate Impact Research (PIK))
Thursday 31 October 2013, 16:2517:00
Coauthors: Niklas Boers (Potsdam Institute for Climate Impact Research ), Veronika Stolbova (Potsdam Institute for Climate Impact Research ), Bodo Bookhagen (UC Santa Barbara, Geography Department)
We investigate the spatial characteristics of extreme rainfall synchronicity of the Indian and South American Summer Monsoon System by means of Complex Networks (CN). By introducing a new combination of CN measures and interpreting it in a climatic context, we investigate climatic linkages and classify the spatial characteristics of extreme rainfall synchronicity. Although our approach is based on only one variable (rainfall), it reveals the most important features of the Monsoon Systems, such as the main moisture pathways, areas with frequent development of Mesoscale Convective Systems, and the major convergence zones. In addition, our results reveal substantial differences between the spatial structures of rainfall synchronicity above the 90th and above the 95th percentiles.
References Arenas, A., A. DiazGuilera, J. Kurths, Y. Moreno, and C. Zhou, Phys. Reports 2008, 469, 93. Boers, N., B. Bookhagen, N. Marwan, J. Kurths, and J. Marengo, Geophys. Res. Lett. 2013, DOI: 10.1002/grl.50681 (online). Donges, J., Y. Zou, N. Marwan, and J. Kurths, Europhys. Lett. 2009, 87, 48007. Malik, N., B. Bookhagen, N. Marwan, and J. Kurths, Climate Dynamics, 2012, 39, 971.
20131104T10:21:01+00:00
1987
1591249
true
16x9
false
no

Decay of correlation for random intermittent maps
ucs_sms_1580157_1606696
http://sms.cam.ac.uk/media/1606696
Decay of correlation for random intermittent maps
Bahsoun, W (Loughborough University)
Monday 25 November 2013, 15:0016:00
Fri, 29 Nov 2013 10:32:02 +0000
Isaac Newton Institute
Bahsoun, W
87e3a68aa404133102f10e5f319a7920
a850a546b4d3b410286d987e78326d14
d49dc36d53f5fb6630210710108b975f
7ba6e00fcfa3c2b4979f19ece73e6dbf
Bahsoun, W (Loughborough University)
Monday 25 November 2013, 15:0016:00
Bahsoun, W (Loughborough University)
Monday 25 November 2013, 15:0016:00
Cambridge University
3780
http://sms.cam.ac.uk/media/1606696
Decay of correlation for random intermittent maps
Bahsoun, W (Loughborough University)
Monday 25 November 2013, 15:0016:00
20131129T10:32:04+00:00
3780
1606696
true
16x9
false
no

Deterministic chaos and diffusion in maps and billiard
ucs_sms_1580157_1599085
http://sms.cam.ac.uk/media/1599085
Deterministic chaos and diffusion in maps and billiard
Klages, R (Queen Mary University of London)
Thursday 14 November 2013, 10:0011:00
Fri, 15 Nov 2013 12:18:54 +0000
Isaac Newton Institute
Klages, R
d12f90dc681a1ca6f5b2a9807cb2269e
0e35dee93c12b10f68750426ddacdeaf
1dd69a86203334fbbe68987f13173424
951357df266633b12608ea45cc7f320d
Klages, R (Queen Mary University of London)
Thursday 14 November 2013,...
Klages, R (Queen Mary University of London)
Thursday 14 November 2013, 10:0011:00
Cambridge University
3660
http://sms.cam.ac.uk/media/1599085
Deterministic chaos and diffusion in maps and billiard
Klages, R (Queen Mary University of London)
Thursday 14 November 2013, 10:0011:00
A fundamental problem of statistical mechanics and dynamical systems theory is to understand transport processes such as diffusion on the basis of deterministic chaos. In my talk I will discuss this issue for deterministic random walks in one and two dimensions generated by simple dynamical systems. For a class of piecewise linear maps lifted onto the whole real line the parameterdependent diffusion coefficient can be calculated exactly analytically. It turns out that the response of these systems to parameter variations is nontrivial by displaying both linear and fractal parameter dependencies in the diffusion coefficient. Computer simulations predict analogous results for Hamiltonian particle billiards like the periodic Lorentz gas. These results are supported by systematic approximations based on a TaylorGreenKubo formula. [1] R.Klages, N.Korabel, Understanding deterministic diffusion by correlated random walks, J.Phys.A: Math. Gen.35, 4823 (2002) [2] R.Klages, Microscopic Chaos, Fractals and Transport in Nonequilibrium Statistical Mechanics (World Scientific, Singapore, 2007)
20131115T12:18:54+00:00
3660
1599085
true
16x9
false
no

Dew droplets and cloud droplets: droplet growth, size distributions, and corrections to scaling
ucs_sms_1580157_1588469
http://sms.cam.ac.uk/media/1588469
Dew droplets and cloud droplets: droplet growth, size distributions, and corrections to scaling
Vollmer, J (MaxPlanckInstitut fur Dynamics and SelfOrganisation)
Tuesday 29 October 2013, 16:2517:00
Wed, 30 Oct 2013 12:57:37 +0000
Isaac Newton Institute
Vollmer, J
91c17f67c159e14006f1063cd291f68f
ef94c9f4e2584bf69232eab233878d2a
f1355ed252d1fa3f90c2b5cf2df32b67
fd1dc850ace5801636a57c2d4fa83737
Vollmer, J (MaxPlanckInstitut fur Dynamics and SelfOrganisation)
Tuesday 29...
Vollmer, J (MaxPlanckInstitut fur Dynamics and SelfOrganisation)
Tuesday 29 October 2013, 16:2517:00
Cambridge University
2718
http://sms.cam.ac.uk/media/1588469
Dew droplets and cloud droplets: droplet growth, size distributions, and corrections to scaling
Vollmer, J (MaxPlanckInstitut fur Dynamics and SelfOrganisation)
Tuesday 29 October 2013, 16:2517:00
I present the results of comprehensive laboratory experiments and numerical studies addressing droplet growth and droplet size distributions in systems where droplets grow due to sustained supersaturation of their environment.
Both, for droplets condensing on a substrate (like dew) and droplets entrained in an external flow (like in clouds), we observe remarkable shortcomings of classical scaling theories addressing these growth processes. The origins of the discrepancies are identified, and appropriate extensions of the theories are discussed.
20131030T12:58:06+00:00
2718
1588469
true
16x9
false
no

Differential Geometry of the SemiGeostrophic and Euler Equations
ucs_sms_1580157_1614569
http://sms.cam.ac.uk/media/1614569
Differential Geometry of the SemiGeostrophic and Euler Equations
Roulstone, I (University of Surrey)
Friday 06 December 2013, 09:4510:30
Fri, 13 Dec 2013 10:28:51 +0000
Isaac Newton Institute
Roulstone, I
8e6d0a9ac369051a4fc53af37e244084
6f4d8fcbbfcf6685106ab20a32f009f4
6a653a3db202c117a1a1a6c677f585f2
e1c1542ff8a1cf03862c6b53f50d1c84
Roulstone, I (University of Surrey)
Friday 06 December 2013, 09:4510:30
Roulstone, I (University of Surrey)
Friday 06 December 2013, 09:4510:30
Cambridge University
2640
http://sms.cam.ac.uk/media/1614569
Differential Geometry of the SemiGeostrophic and Euler Equations
Roulstone, I (University of Surrey)
Friday 06 December 2013, 09:4510:30
The role of contact and symplectic geometry of the semigeostophic (SG) equations, in describing their Legendrian and Hamiltonian properties, will be reviewed. Using the geometry of 2forms in 4 dimensions and the geometry of 3forms in 6 dimensions, we show that the incompressible Euler equations in 2 and 3 dimensions admit geometric structures akin to the those present in the SG equations.
20131213T10:28:51+00:00
2640
1614569
true
16x9
false
no

Direct Statistical Simulation of a TwoLayer Primitive Equation Model
ucs_sms_1580157_1612274
http://sms.cam.ac.uk/media/1612274
Direct Statistical Simulation of a TwoLayer Primitive Equation Model
Marston, B (Brown University)
Wednesday 04 December 2013, 11:3012:15
Mon, 09 Dec 2013 11:54:14 +0000
Isaac Newton Institute
Marston, B
160d25c33c0aa149f40ad4bb1913b4c9
17eb26708f79cd49ef07fc1b44685d82
9cc2f04c7af5fe3fb9653cfae902fa6b
67f1568e0259f19fe0a40434663ba183
Marston, B (Brown University)
Wednesday 04 December 2013, 11:3012:15
Marston, B (Brown University)
Wednesday 04 December 2013, 11:3012:15
Cambridge University
2959
http://sms.cam.ac.uk/media/1612274
Direct Statistical Simulation of a TwoLayer Primitive Equation Model
Marston, B (Brown University)
Wednesday 04 December 2013, 11:3012:15
Coauthors: Wanming Qi (Brown University), Steve Tobias (University of Leeds)
Loworder statistics of the largescale circulation of planetary atmospheres may be directly accessed by solving the equations of motion for the equaltime statistics. We implement such Direct Statistical Simulation of a twolayer primitive equation model by systematic expansion in the cumulants. The first cumulant is the zonally averaged vorticity, divergence, and temperature as a function of latitude and level, and the second cumulant contains information about nonlocal teleconnections. At second order (CE2) the expansion retains the eddy – meanflow interaction but neglects eddyeddy interactions and is realizable. Eddyeddy interactions appear at third (CE3) order, but care must be taken to maintain realizability with a nonnegative probability distribution function. The cumulant expansion is conservative, orderby order, in the total angular momentum, total energy, and meansquared potential temperature. An intermediate approximation, CE2.5, is related to the Edd yDamped QuasiNormal Markovian (EDQNM) approximation and maintains realizability at the expense of the introduction of a phenomenological timescale for eddy damping. First and second cumulants accumulated by timeintegration of the twolayer primitive equations are compared with those obtained at the fixed points found at CE2, CE2.5, and CE3 levels of approximation, and against statistics obtained from reanalysis of the midlevel atmosphere of the Earth. CE2 reproduces qualitative features of the zonal mean general circulation such as the midlatitude jets. CE2.5 and CE3 improve quantitative agreement in both the zonal means, and in the teleconnections.
20131209T11:54:14+00:00
2959
1612274
true
16x9
false
no

Direct Statistical Simulation of Jet Formation in Local and Global Geometries
ucs_sms_1580157_1612171
http://sms.cam.ac.uk/media/1612171
Direct Statistical Simulation of Jet Formation in Local and Global Geometries
Tobias, S (University of Leeds)
Tuesday 03 December 2013, 16:0016:45
Mon, 09 Dec 2013 10:19:57 +0000
Isaac Newton Institute
Tobias, S
2caa221df23c469def8c215e682852da
0497fc028ca186e073cd57d460fbe5ed
46c66648376e4c4d8b8196e3c1004926
4d7bd12e1979a95916a181ee0a320f71
Tobias, S (University of Leeds)
Tuesday 03 December 2013, 16:0016:45
Tobias, S (University of Leeds)
Tuesday 03 December 2013, 16:0016:45
Cambridge University
2920
http://sms.cam.ac.uk/media/1612171
Direct Statistical Simulation of Jet Formation in Local and Global Geometries
Tobias, S (University of Leeds)
Tuesday 03 December 2013, 16:0016:45
Coauthor: Brad Marston (Brown University)
We present Direct Statistical Simulation (DSS) of jet formation. We consider the simplest barotropic model both on a spherical surface and a local betaplane. DSS involves the direct solution of the loworder statistics via an expansion in cumulants. In both cases we compare the results of our DSS with statistics obtained from long DNS simulations. We discuss in what circumstances truncating the cumulant expansion at second order (thereby including eddy – meanflow interaction but neglecting eddyeddy interactions for the fluctuating fields) gives a good description of the dynamics of the flow. We demonstrate that this depends on the degree of lack of statistical equilibrium in the flow (as measured by the Zonostrophy parameter). We discuss briefly how to proceed to higher order to include eddyeddy interactions and the possibility of forward and inverse cascades.
20131209T10:19:57+00:00
2920
1612171
true
16x9
false
no

Efficiency, Irreversibility, and Tipping Points in Climate Dynamics
ucs_sms_1580157_1598984
http://sms.cam.ac.uk/media/1598984
Efficiency, Irreversibility, and Tipping Points in Climate Dynamics
Lucarini, V (Universität Hamburg)
Wednesday 13 November 2013, 11:0012:00
Fri, 15 Nov 2013 10:16:43 +0000
Isaac Newton Institute
Lucarini, V
9990b6052cef8723ca17d3a74331cc45
d106f1cfd61911c8d5a1fc25d48f86bc
acc3cfeb4a6b63f3195dad7d864a630b
036e5a03ccf20385d990dc86bb8f909c
Lucarini, V (Universität Hamburg)
Wednesday 13 November 2013, 11:0012:00
Lucarini, V (Universität Hamburg)
Wednesday 13 November 2013, 11:0012:00
Cambridge University
3468
http://sms.cam.ac.uk/media/1598984
Efficiency, Irreversibility, and Tipping Points in Climate Dynamics
Lucarini, V (Universität Hamburg)
Wednesday 13 November 2013, 11:0012:00
20131115T10:16:43+00:00
3468
1598984
true
16x9
false
no

Efficient sampling of rare events by splitting
ucs_sms_1580157_1589168
http://sms.cam.ac.uk/media/1589168
Efficient sampling of rare events by splitting
Crommelin, DTC (Centrum voor Wiskunde en Informatica (CWI))
Thu, 31 Oct 2013 12:47:37 +0000
Isaac Newton Institute
Crommelin, DTC
28e780fa077b65add048510f75e62c82
3f5f8c8dc821300e4714920294c4cdfb
a3ce3d6e10361ba71f2c7f320ebb2bb2
af8af5ce4ae1168a982835aa9938de7a
Crommelin, DTC (Centrum voor Wiskunde en Informatica (CWI))
Crommelin, DTC (Centrum voor Wiskunde en Informatica (CWI))
Cambridge University
2057
http://sms.cam.ac.uk/media/1589168
Efficient sampling of rare events by splitting
Crommelin, DTC (Centrum voor Wiskunde en Informatica (CWI))
Standard (or crude) Monte Carlo (MC) simulation is known to be inefficient for simulating rare events. For events with low probability, the squared relative error on estimates obtained from straightforward MC simulation is inversely proportional to the number of samples, so that an excessively large number of samples may be required to reach a desired accuracy for the estimation of rare event probabilities.
To improve the efficiency of MC sampling for rare events, various techniques have been developed in the past, for applications in e.g. communication networks and reliability analysis. Such techniques can be of interest for studying extremes in geophysical models. I will discuss a technique called multilevel splitting, in which model sample paths are split into multiple copies each time they cross thresholds (or levels) that lead closer to the rare event set.
20131031T12:48:11+00:00
2057
1589168
true
16x9
false
no

Emergent Constraints on Earth System Sensitivities
ucs_sms_1580157_1591214
http://sms.cam.ac.uk/media/1591214
Emergent Constraints on Earth System Sensitivities
Cox, PM (University of Exeter)
Thursday 31 October 2013, 11:4512:20
Mon, 04 Nov 2013 11:27:49 +0000
Isaac Newton Institute
Cox, PM
3212489cde232ecc1a12a29ea24fc0ed
57402300d7b845920eac1833a0c14feb
dd93726c42a92a556ae92799a5732901
1d3f4a1c6a2652cdf15567c8337efd68
Cox, PM (University of Exeter)
Thursday 31 October 2013, 11:4512:20
Cox, PM (University of Exeter)
Thursday 31 October 2013, 11:4512:20
Cambridge University
1949
http://sms.cam.ac.uk/media/1591214
Emergent Constraints on Earth System Sensitivities
Cox, PM (University of Exeter)
Thursday 31 October 2013, 11:4512:20
Coauthor: Chris Huntingford (Centre for Ecology and Hydrology)
Climate and Earth System Models are designed to project changes in the climatecarbon cycle system over the coming centuries. These models have ever higher spatial resolution and are based on an improving understanding of key processes. However, climate modelling still suffers from a significant timescale problem – we need to find constraints on the huge range of projected changes in the climatecarbon system over the next century, but the observational data that we have relates to much shorter timescales. This talk will summarise one promising way around the timescale problem  the use of “Emergent Constraints”. An Emergent Constraint is a relationship between some climate system sensitivity to anthropogenic forcing and an observable (or already observed) feature of the climate system. We call it emergent because it emerges from the ensemble of models, and it is described as a constraint because it enables an observation to constrain the estimate of the cli mate system sensitivity in the real world. As an example, I will describe an emergent constraint on the projected loss of tropical land carbon under climate change, which has a huge range amongst climatecarbon cycle projections for the 21st century. We have recently identified an emergent linear relationship across the ensemble of models between the sensitivity of tropical landcarbon storage to warming and the sensitivity of the annual growthrate in atmospheric CO2 to tropical temperature anomalies. When combined with contemporary observations of the atmospheric CO2 concentration and the tropical temperature, this relationship provides a tight constraint on the sensitivity of tropical land carbon to warming in the real climate system (Cox et al., Nature, 2013). The talk will conclude by hypothesising how such emergent constraints may relate to (a) the FluctuationDissipation Theorem and (b) Timeseries Precursors of Tipping Points.
20131104T11:28:18+00:00
1949
1591214
true
16x9
false
no

Energy cascades in the baroclinic ocean winddriven double gyre problem
ucs_sms_1580157_1609084
http://sms.cam.ac.uk/media/1609084
Energy cascades in the baroclinic ocean winddriven double gyre problem
Straub, D (McGill University)
Monday 02 December 2013, 16:0016:45
Tue, 03 Dec 2013 14:38:44 +0000
Isaac Newton Institute
Straub, D
1dd40b40429e7875b8d56b7d2ab5f2de
0b2047eb687c20bb8f6aef2f1d3b39c2
10a7c7b190305b9a9b1c80870058850a
e29280841925f5b80ed9ea278cab06c1
Straub, D (McGill University)
Monday 02 December 2013, 16:0016:45
Straub, D (McGill University)
Monday 02 December 2013, 16:0016:45
Cambridge University
3047
http://sms.cam.ac.uk/media/1609084
Energy cascades in the baroclinic ocean winddriven double gyre problem
Straub, D (McGill University)
Monday 02 December 2013, 16:0016:45
Coauthor: David Straub
We consider the classic baroclinic quasigeostrophic winddriven ocean double gyre problem over a range of deformation radii, wind stress amplitudes, and bottom friction coefficients with an aim of understanding transfer of energy across scales. In this betaplane basin setting, we find significant differences from classic studies of gestrophic turbulence, which generally assume zonal periodicity. In a basin geometry, the beta term (related to a latitudinal dependence in the Corioils parameter) can play a key role. For example, it can be the dominant term allowing for energy transfer between the basin scale and the baroclinic mesoscale. We also find that barotropization of baroclinic mesoscale energy forces the barotropic mode at scales where the barotropic mode is most energetic. Related to this, the barotropic nonlinear inverse energy cascade does not extend between mesoscale injection and large scale dissipation wavenumbers, as is often assumed. Instead, it is part of a ``double cascade" of barotropic energy in which the nonlinear inverse cascade is nearly offset by a forward cascade associated with the beta term. This is particularly evident in weak bottom drag simulations, for which a time eddymean flow decomposition reveals the double cascade to beassociated with the eddyonly terms.
20131203T14:38:44+00:00
3047
1609084
true
16x9
false
no

Environmental superstatistics
ucs_sms_1580157_1589154
http://sms.cam.ac.uk/media/1589154
Environmental superstatistics
Beck, C (Queen Mary, University of London)
Wednesday 30 October 2013, 09:3510:10
Thu, 31 Oct 2013 12:43:17 +0000
Isaac Newton Institute
Beck, C
de291027d576e08f9a790d595e4a22fc
ed8c66a21d51980254fef8e0b6be45ad
267a987b51a169e8ee69a08e68d3650e
ac5b0418b61ad29e11a0ac3f8d53836d
Beck, C (Queen Mary, University of London)
Wednesday 30 October 2013,...
Beck, C (Queen Mary, University of London)
Wednesday 30 October 2013, 09:3510:10
Cambridge University
2447
http://sms.cam.ac.uk/media/1589154
Environmental superstatistics
Beck, C (Queen Mary, University of London)
Wednesday 30 October 2013, 09:3510:10
Complex systems in driven nonequilibrium situations often consist of a superposition of several dynamics on wellseparated time scales. Sometimes the parameters of the system fluctuate as well, on a much larger time scale than the local dynamics. The resulting marginal distributions typically have fat tails, which can be understood by superstatistical techniques. After a short review of the field I will concentrate on some examples relevant for planet earth: The dynamics of tracer particles in turbulent flows, the surface temperature statistics at various locations on planet earth, and the dynamics of sea levels.
20131031T12:43:50+00:00
2447
1589154
true
16x9
false
no

Exponential Decay of the Power Spectrum and Finite Dimensionality for Solutions of the Three Dimensional Primitive Equations
ucs_sms_1580157_1609077
http://sms.cam.ac.uk/media/1609077
Exponential Decay of the Power Spectrum and Finite Dimensionality for Solutions of the Three Dimensional Primitive Equations
Petcu, M (Université de Poitiers)
Monday 02 December 2013, 14:4515:30
Tue, 03 Dec 2013 14:29:42 +0000
Isaac Newton Institute
Petcu, M
f26bb69af635bddf5baa7c3ebadbe850
19ecc91afbdf68fc89a4708287452db4
03682ac16347f64d076e032db7713162
c56fa9bc47734d06775aa54e96f9f2d4
Petcu, M (Université de Poitiers)
Monday 02 December 2013, 14:4515:30
Petcu, M (Université de Poitiers)
Monday 02 December 2013, 14:4515:30
Cambridge University
2540
http://sms.cam.ac.uk/media/1609077
Exponential Decay of the Power Spectrum and Finite Dimensionality for Solutions of the Three Dimensional Primitive Equations
Petcu, M (Université de Poitiers)
Monday 02 December 2013, 14:4515:30
The purpose of this talk is to estimate the number of modes, volumes and nodes, sufficient to describe well the solution of the three dimensional primitive equations; the physical meaning of these estimates is also discussed. We also study the exponential decay of the spatial power spectrum for the three dimensional primitive equations.
20131203T14:29:42+00:00
2540
1609077
true
16x9
false
no

Extreme Events and Coupled ClimateEconomics Modeling
ucs_sms_1580157_1591193
http://sms.cam.ac.uk/media/1591193
Extreme Events and Coupled ClimateEconomics Modeling
Ghil, M (Ecole Normale Supérieure, Paris & UCLA)
Thursday 31 October 2013, 09:0009:35
Mon, 04 Nov 2013 10:17:50 +0000
Isaac Newton Institute
Ghil, M
c1cf6d30e4af913a870823085176251f
45204c1011cbf905bfbd767e477caa8d
b779b825fe7bedeb66d6bd795eaded7c
d9261971d9b2e2df223b6aa870c7eb0b
Ghil, M (Ecole Normale Supérieure, Paris & UCLA)
Thursday 31 October 2013,...
Ghil, M (Ecole Normale Supérieure, Paris & UCLA)
Thursday 31 October 2013, 09:0009:35
Cambridge University
3068
http://sms.cam.ac.uk/media/1591193
Extreme Events and Coupled ClimateEconomics Modeling
Ghil, M (Ecole Normale Supérieure, Paris & UCLA)
Thursday 31 October 2013, 09:0009:35
In this talk, I will review some recent work on extreme events, their causes and consequences. The review covers theoretical aspects of time series analysis and of extreme value theory, as well as of the deterministic modeling of extreme events, via continuous and discrete dynamic models. The applications include climatic, seismic and socioeconomic events, along with their prediction. Two important results refer to (i) the complementarity of spectral analysis of a time series in terms of the continuous and the discrete part of its power spectrum; and (ii) the need for coupled modeling of natural and socioeconomic systems. Both these results have implications for the study and prediction of natural hazards and their human impacts. A substantial part of the talk will deal with an endogenous business cycle (EnBC) model and with the way that EnBCs affect the impact of natural hazards on a dynamic economy. An outofequilibrium fluctuationdissipation result for macroeconomics is inferred from the model and confirmed by the analysis of US economic data.
20131104T10:18:26+00:00
3068
1591193
true
16x9
false
no

Extreme events and the multifractal butterfly effect
ucs_sms_1580157_1591242
http://sms.cam.ac.uk/media/1591242
Extreme events and the multifractal butterfly effect
Lovejoy, S (McGill University)
Thursday 31 October 2013, 15:5016:25
Mon, 04 Nov 2013 10:19:51 +0000
Isaac Newton Institute
Lovejoy, S
9078706d65a629d29e72e00694878825
30ebe1dfd5ac633d6e6a43ce5279fee8
5a22ec9acbd07ce7b81116afd10fa570
60596648787021f34da9d76d1e2187e8
Lovejoy, S (McGill University)
Thursday 31 October 2013, 15:5016:25
Lovejoy, S (McGill University)
Thursday 31 October 2013, 15:5016:25
Cambridge University
2090
http://sms.cam.ac.uk/media/1591242
Extreme events and the multifractal butterfly effect
Lovejoy, S (McGill University)
Thursday 31 October 2013, 15:5016:25
Scaling processes abound in geophysics and this has important consequences for the probability distributions of the corresponding intensive and extensive geophysical variables. Classical scaling processes – such as in classical turbulence – are selfsimilar, they are characterized by exponents which are invariant under isotropic scale changes. However, the atmosphere and lithosphere are strongly stratified so that we must generalize the notion of scale allowing for invariance under anisotropic zooms. When this is done, it is often found that scaling can apply over huge ranges, up to planetary in extent. It is now clear that the generic scaling process is the multifractal cascade in which a scale invariant dynamical mechanism repeats (multiplicatively) from scale to scale; anisotropic scaling – and multifractal universality classes  imply that multifractals are widely relevant in the earth sciences. General (canonical) multifractal processes developed over finite ranges of scale and analyzed at their smallest scale (the “bare” process), have “longtailed” distributions (e.g. the lognormal). However the small scale cascade limit is singular so that the integration/averaging of cascades developed down to their small scale limits leads to “dressed” properties characterized notably by “fattailed” power law probability distributions Pr(x>s)=s**qD where x is a random value, s a threshold and qD the critical exponent implying that the moments for q>qD diverge. For cascades averaged over scales larger than the inne r cascade scale, the moments q>qD are no longer determined by the large scale finite by the small scale details: the “multifractal butterfly effect”. The sampling properties of such processes can be understood with “multifractal phase transitions”; we review this as well as evidence for the divergence of moments in laboratory, atmospheric and climatological series, and in data from the solid earth and discuss implications (abrupt changes, etc.).
20131104T10:20:27+00:00
2090
1591242
true
16x9
false
no

Extreme value theory for randomly perturbed systems: getting the local dimensions
ucs_sms_1580157_1588455
http://sms.cam.ac.uk/media/1588455
Extreme value theory for randomly perturbed systems: getting the local dimensions
Vaienti, S (Centre de Physique Théorique, Marseille)
Tuesday 29 October 2013, 14:1514:50
Wed, 30 Oct 2013 12:30:30 +0000
Isaac Newton Institute
Vaienti, S
c158a40fca1ccd6c50b70a84d1e8b90c
dbbb97db1e8c1d125c611ece16e99025
dfd3e7c32d6c79180d0a570407b721fc
e0c7f0e81ee1ccd18f6d54eea2dda68c
Vaienti, S (Centre de Physique Théorique, Marseille)
Tuesday 29 October 2013,...
Vaienti, S (Centre de Physique Théorique, Marseille)
Tuesday 29 October 2013, 14:1514:50
Cambridge University
1822
http://sms.cam.ac.uk/media/1588455
Extreme value theory for randomly perturbed systems: getting the local dimensions
Vaienti, S (Centre de Physique Théorique, Marseille)
Tuesday 29 October 2013, 14:1514:50
We present some new results for extreme values distributions in dynamical systems perturbed "via" random transformations and with observational noise. In both cases the linear scaling parameters of the Gumbel law will allow to get informations on the local behavior respectively of the stationary measure (random transformations), and of the invariant measure (observational noise). This collects work done with Aytac, Faranda, Freitas, Lucarini and Turchetti.
20131030T12:31:06+00:00
1822
1588455
true
16x9
false
no

Extreme values for deterministic and random dynamical systems
ucs_sms_1580157_1648297
http://sms.cam.ac.uk/media/1648297
Extreme values for deterministic and random dynamical systems
Freitas, JM (Centro de Matematica da Universidade do Porto)
Wednesday 18 December 2013, 14:0015:00
Mon, 03 Feb 2014 15:48:48 +0000
Isaac Newton Institute
Freitas, JM
c53f3ef4feef999b2d09c5b1998fae08
3f3aee886d3d50e71319179509279119
011091ee446e022ea12121659ed22186
22c6bfd587e494d00b7d4c3997788224
Freitas, JM (Centro de Matematica da Universidade do Porto)
Wednesday 18...
Freitas, JM (Centro de Matematica da Universidade do Porto)
Wednesday 18 December 2013, 14:0015:00
Cambridge University
3660
http://sms.cam.ac.uk/media/1648297
Extreme values for deterministic and random dynamical systems
Freitas, JM (Centro de Matematica da Universidade do Porto)
Wednesday 18 December 2013, 14:0015:00
It is well known that the Extremal Index (EI) measures the intensity of clustering of extreme events in stationary processes. We sill see that for some certain uniformly expanding systems there exists a dichotomy based on whether the rare events correspond to the entrance in small balls around a periodic point or a nonperiodic point. In fact, either there exists EI in (0,1) around (repelling) periodic points or the EI is equal to 1 at every nonperiodic point. The main assumption is that the systems have sufficient decay of correlations of observables in some Banach space against all L1observables. Then we consider random perturbations of uniformly expanding systems, such as piecewise expanding maps of the circle. We will see that, in this context, for additive absolutely continuous noise (w.r.t. Lebesgue), the dichotomy vanishes and the EI is always 1
20140203T15:48:48+00:00
3660
1648297
true
16x9
false
no

Extremes as indicators of critical transitions
ucs_sms_1580157_1648304
http://sms.cam.ac.uk/media/1648304
Extremes as indicators of critical transitions
Lucarini, V (Universität Hamburg)
Thursday 19 December 2013, 10:0011:00
Mon, 03 Feb 2014 15:50:14 +0000
Isaac Newton Institute
Lucarini, V
90e8a33c56990dafdcb74194c4d18143
a0085031fb7f1a21f3fb2b4d9c92ada9
c74d0c948c19ab42bda9f009d202a324
540bb7fbde9ab21423907df81f3913a5
Lucarini, V (Universität Hamburg)
Thursday 19 December 2013, 10:0011:00
Lucarini, V (Universität Hamburg)
Thursday 19 December 2013, 10:0011:00
Cambridge University
3720
http://sms.cam.ac.uk/media/1648304
Extremes as indicators of critical transitions
Lucarini, V (Universität Hamburg)
Thursday 19 December 2013, 10:0011:00
20140203T15:50:14+00:00
3720
1648304
true
16x9
false
no

Extremes in Chaotic Dynamical Systems: Theory and Applications
ucs_sms_1580157_1606189
http://sms.cam.ac.uk/media/1606189
Extremes in Chaotic Dynamical Systems: Theory and Applications
Lucarini, V (Universität Hamburg)
Monday 25 November 2013, 11:0012:00
Thu, 28 Nov 2013 12:01:44 +0000
Isaac Newton Institute
Lucarini, V
d0f784372613fcfa214342c312688ab6
e5499ad6c1ae2138bdb05a1ac83ace4d
20097af65acc8cfb1bc6340a59308288
f176988576a6ecd847fcc5ad2b3157d9
Lucarini, V (Universität Hamburg)
Monday 25 November 2013, 11:0012:00
Lucarini, V (Universität Hamburg)
Monday 25 November 2013, 11:0012:00
Cambridge University
3900
http://sms.cam.ac.uk/media/1606189
Extremes in Chaotic Dynamical Systems: Theory and Applications
Lucarini, V (Universität Hamburg)
Monday 25 November 2013, 11:0012:00
20131128T12:01:44+00:00
3900
1606189
true
16x9
false
no

From simple particle models to PDE dynamics
ucs_sms_1580157_1612267
http://sms.cam.ac.uk/media/1612267
From simple particle models to PDE dynamics
Zimmer, J (University of Bath)
Wednesday 04 December 2013, 10:1511:00
Mon, 09 Dec 2013 11:51:08 +0000
Isaac Newton Institute
Zimmer, J
5a10ee11b21de662d00734e486fec595
c0e51f92d9f338512cfdb817c2c4ff71
7f1292a57284fb4beb96180bba84c8eb
792345f4c5c52b2d8817d884fa27db46
Zimmer, J (University of Bath)
Wednesday 04 December 2013, 10:1511:00
Zimmer, J (University of Bath)
Wednesday 04 December 2013, 10:1511:00
Cambridge University
2811
http://sms.cam.ac.uk/media/1612267
From simple particle models to PDE dynamics
Zimmer, J (University of Bath)
Wednesday 04 December 2013, 10:1511:00
One often aims to describe systems out of equilibrium by the governing energy E and entropy S, as well as the corresponding evolution laws for E and S. How can we derive these ingredients of the macroscopic evolution from particle models? In recent years, a dynamic scalebridging approach has been developed and applied to a number of problems; large deviation theory plays an important role. The talk will present some of these results, focussing on the derivation of the Wassersteinentropy formulation of diffusion and the VlasovFokkerPlanck equation as a system driven by energy and entropy. Time permitting, an approach of deriving stochastic equations mimicking the fluctuations in underlying mesoscopic models will be sketched. This is joint work with Hong Duong, Rob Jack and Mark. A. Peletier.
20131209T11:51:08+00:00
2811
1612267
true
16x9
false
no

Generalized additive modelling of hydrological sample extremes
ucs_sms_1580157_1591235
http://sms.cam.ac.uk/media/1591235
Generalized additive modelling of hydrological sample extremes
ChavezDemoulin, V (ETH Zürich)
Thursday 31 October 2013, 14:5015:25
Mon, 04 Nov 2013 10:16:30 +0000
Isaac Newton Institute
ChavezDemoulin, V
752e916792b9cbd37a2c69666004019f
3cbc8d290099b8672d72bffe1f980a43
4c6152e74cc7c4c4cd67523bb225c32e
0de24187aae6bf06731e4ce119d93eb2
ChavezDemoulin, V (ETH Zürich)
Thursday 31 October 2013, 14:5015:25
ChavezDemoulin, V (ETH Zürich)
Thursday 31 October 2013, 14:5015:25
Cambridge University
2059
http://sms.cam.ac.uk/media/1591235
Generalized additive modelling of hydrological sample extremes
ChavezDemoulin, V (ETH Zürich)
Thursday 31 October 2013, 14:5015:25
Coauthors: Anthony Davison (EPFL, Lausanne), Marius Hofert (ETHZ, Zurich)
Estimation of flood frequencies and severities is important for many water management issues. We present a smoothing extreme value method fitted by penalized loglikelihood. Spline smoothing is used to estimate the parameters of the frequency and size distributions of extremes, depending on covariates in a non or semiparametric way. The frequency process of high level extremes is modelled by a Poisson process, either homogeneous or nonhomogeneous. The extreme sizes are considered to follow a generalized Pareto distribution. Being given by two parameters, the method of spline smoothing is not straightforward to apply. An efficient fitting algorithm based on orthogonal reparametrisation is developed to achieve this task. The method is applied to the daily maximum flows of an hydrological station in Switzerland and is used to estimate 20year return levels.
20131104T10:17:47+00:00
2059
1591235
true
16x9
false
no

Generalized Large Scale Semigeostrophic Equations: geometric structure and global wellposedness
ucs_sms_1580157_1613258
http://sms.cam.ac.uk/media/1613258
Generalized Large Scale Semigeostrophic Equations: geometric structure and global wellposedness
Vasylkevych, S (Jacobs University Bremen)
Thursday 05 December 2013, 14:4515:30
Tue, 10 Dec 2013 09:49:59 +0000
Isaac Newton Institute
Vasylkevych, S
3fba26abdb852bf3d60660948321b49f
c4eef74d7136f34652518350bba783a2
74aa15e2d82ed62888c7dc443a4897e2
2a5a4b1962d7f6e7a3610324cf92db03
Vasylkevych, S (Jacobs University Bremen)
Thursday 05 December 2013,...
Vasylkevych, S (Jacobs University Bremen)
Thursday 05 December 2013, 14:4515:30
Cambridge University
2947
http://sms.cam.ac.uk/media/1613258
Generalized Large Scale Semigeostrophic Equations: geometric structure and global wellposedness
Vasylkevych, S (Jacobs University Bremen)
Thursday 05 December 2013, 14:4515:30
Coauthors: Marcel Oliver (Jacobs University), Mahmut Calik (Jacobs University)
We derive and study a family of approximate Hamiltonian balance models (called GLSG) for rotating shallow water in the semigeostrophic limit with spatially varying Coriolis parameter and nontrivial bottom topology. The models can be formulated in terms of an advected potential vorticity with a nonlinear vorticity inversion relation and include L_1 and LSG models proposed by R. Salmon as special cases.
We prove existence and uniqueness of global classical solutions to the GLSG equations for certain members of the family and study the PV invertibility as a function of the parameters.
20131210T09:49:59+00:00
2947
1613258
true
16x9
false
no

Geodesic flows: Mixing, zeta functions and resonances
ucs_sms_1580157_1588413
http://sms.cam.ac.uk/media/1588413
Geodesic flows: Mixing, zeta functions and resonances
Pollicott, M (University of Warwick)
Tuesday 29 October 2013, 09:0009:35
Wed, 30 Oct 2013 12:11:49 +0000
Isaac Newton Institute
Pollicott, M
78a4ffdf9e395968ab8419a97866395f
2e1f945366619e16d080a5a33d3bf84b
3d6f7265654c5472444faee55f3909ad
f34dc1a54a223a233b291f6401ad9d5f
Pollicott, M (University of Warwick)
Tuesday 29 October 2013, 09:0009:35
Pollicott, M (University of Warwick)
Tuesday 29 October 2013, 09:0009:35
Cambridge University
2458
http://sms.cam.ac.uk/media/1588413
Geodesic flows: Mixing, zeta functions and resonances
Pollicott, M (University of Warwick)
Tuesday 29 October 2013, 09:0009:35
Historically important examples of ``chaotic'' dynamical systems are Anosov flows, in particular, and geodesic flows on negatively curved manifolds. In particular, they provide a concrete setting to explore a wealth of interesting topics: (i) mixing rates (which can be studied using zeta function and resonances); (ii) large deviations and fluctuation theorems (GallavottiCohen theorem in nonequilibrium statistical mechanics); and (iii) escape rates (the rate at which mass escapes from an open system) and extremes.
20131030T12:12:35+00:00
2458
1588413
true
16x9
false
no

Hamiltonian balance models: derivation, structure, and analysis
ucs_sms_1580157_1606182
http://sms.cam.ac.uk/media/1606182
Hamiltonian balance models: derivation, structure, and analysis
Oliver, M (Jacobs University Bremen)
Monday 25 November 2013, 10:0011:00
Thu, 28 Nov 2013 11:58:31 +0000
Isaac Newton Institute
Oliver, M
151a2cc2ca91e2389d378cd80af825bf
9ee04c0bbcf02bf76f4f71f78339e26e
480d3310fd94af32d54106775c74bdb8
98846e3a5da91dbe8d5d0edff93ce79e
Oliver, M (Jacobs University Bremen)
Monday 25 November 2013, 10:0011:00
Oliver, M (Jacobs University Bremen)
Monday 25 November 2013, 10:0011:00
Cambridge University
3720
http://sms.cam.ac.uk/media/1606182
Hamiltonian balance models: derivation, structure, and analysis
Oliver, M (Jacobs University Bremen)
Monday 25 November 2013, 10:0011:00
I will give an overview on balance models within the simplified > setting of the rotating shallow water equations, explain their Hamiltonian > structure, derivation via variational principles, and analytical properties.
20131128T11:58:31+00:00
3720
1606182
true
16x9
false
no

Hurricane dynamics: on the role of Vortex Rossby Waves (VRWs)
ucs_sms_1580157_1587756
http://sms.cam.ac.uk/media/1587756
Hurricane dynamics: on the role of Vortex Rossby Waves (VRWs)
Brunet, G (Weather Science, Met Office)
Monday 28 October 2013, 11:0012:00
Tue, 29 Oct 2013 10:48:26 +0000
Isaac Newton Institute
Brunet, G
62402b669f2767486f5c475d1756b426
f2cb4d823c605043dd4c0ff3a1850abf
1f328231072f1b8708134d0d86d02d96
64b2b426f0f4f5cfdc471c73fdb5125c
Brunet, G (Weather Science, Met Office)
Monday 28 October 2013, 11:0012:00
Brunet, G (Weather Science, Met Office)
Monday 28 October 2013, 11:0012:00
Cambridge University
3720
http://sms.cam.ac.uk/media/1587756
Hurricane dynamics: on the role of Vortex Rossby Waves (VRWs)
Brunet, G (Weather Science, Met Office)
Monday 28 October 2013, 11:0012:00
Despite the fact that asymmetries in hurricanes, such as spiral rainbands, polygonal eyewalls and mesovortices, have long been observed in radar imagery, many aspects of their dynamics still remain unsolved, particularly in the formation of the secondary eyewall. To fill this gap, a simple 2D barotropic model (Martinez et al., 2010) and the highresolution PSUNCAR nonhydrostatic mesoscale model (MM5) are used to study hurricane asymmetries (Chen et al., 2003; Martinez et al., 2011).The Empirical Normal Mode (ENM) diagnostics (Brunet, 1994), together with the EliassenPalm (EP) flux calculations are used to isolate wave modes from the model datasets to investigate their impact on the changes in the structure and intensity of the simulated hurricanes (Chen et al., 2003). The ENMs are obtained in a similar manner as Empirical Orthogonal Functions (EOFs) but with the use of a quadratic form instead of Euclidean norm. The quadratic forms are global invariants, the pseudomomentum and pseudoenergy wave activities, of the linearized equations about a basic state (Brunet and Vautard, 1996). ENM theory bridges two important diagnostic tools of geophysical fluid dynamics: principal component analysis and normal mode theory. The role of internal dynamics on concentric eyewall genesis is further evaluated using the full physics MM5 simulation. The leading modes of the ENM diagnostics exhibit mainly characteristics of VRWs and their contribution to the EP flux divergence induced two regions of maximum tangential wind acceleration; one inside the primary eyewall which accounts for eyewall contraction and the other outside the primary eyewall which explains the development of the secondary eyewall (Martinez et al., 2011). We will point out the expected implication of these results in the context of numerical weather prediction at different spacetime resolutions for intensifying and mature hurricanes of different strengths.
20131029T10:48:55+00:00
3720
1587756
true
16x9
false
no

Hydrodynamic turbulence as a problem in nonequilibrium statistical mechanics
ucs_sms_1580157_1591692
http://sms.cam.ac.uk/media/1591692
Hydrodynamic turbulence as a problem in nonequilibrium statistical mechanics
Ruelle, DP (IHES)
Friday 01 November 2013, 09:0009:35
Mon, 04 Nov 2013 11:54:08 +0000
Isaac Newton Institute
Ruelle, DP
2f66f08cc784688140c7e0fefb0cb185
2804d5e88342abe8a79810da6799e5ec
b67fa5ac159773b8c11a2ec11b611779
c3e5c838b669147b64925ee00e17ced0
Ruelle, DP (IHES)
Friday 01 November 2013, 09:0009:35
Ruelle, DP (IHES)
Friday 01 November 2013, 09:0009:35
Cambridge University
2689
http://sms.cam.ac.uk/media/1591692
Hydrodynamic turbulence as a problem in nonequilibrium statistical mechanics
Ruelle, DP (IHES)
Friday 01 November 2013, 09:0009:35
The problem of hydrodynamic turbulence is reformulated as a heat flow problem along a chain of mechanical systems which describe units of fluid of smaller and smaller spatial extent. These units are macroscopic but have few degrees of freedom, and can be studied by the methods of (microscopic) nonequilibrium statistical mechanics. The fluctuations predicted by statistical mechanics correspond to the intermittency observed in turbulent flows. Specifically, we obtain the formula
ζp=p3−1lnκlnΓ(p3+1)
for the exponents of the structure functions (⟨Δrvp⟩∼rζp). The meaning of the adjustable parameter κ is that when an eddy of size r has decayed to eddies of size r/κ their energies have a thermal distribution. The above formula, with (lnκ)−1=.32±.01 is in good agreement with experimental data. This lends support to our physical picture of turbulence, a picture which can thus also be used in related problems.
20131104T11:54:39+00:00
2689
1591692
true
16x9
false
no

Interplay between Mathematics and Physics
ucs_sms_1580157_1588441
http://sms.cam.ac.uk/media/1588441
Interplay between Mathematics and Physics
Wang, S (Indiana University)
Tuesday 29 October 2013, 11:4512:20
Wed, 30 Oct 2013 12:33:12 +0000
Isaac Newton Institute
Wang, S
ea3e155a94f159f4f1a5251b464d0a5b
86d5a7e5786ddb650d8808a50a988adc
86fece9495222dbb52e2c54583361cf4
435b54c6338f0149aaf89a08233465bb
Wang, S (Indiana University)
Tuesday 29 October 2013, 11:4512:20
Wang, S (Indiana University)
Tuesday 29 October 2013, 11:4512:20
Cambridge University
2251
http://sms.cam.ac.uk/media/1588441
Interplay between Mathematics and Physics
Wang, S (Indiana University)
Tuesday 29 October 2013, 11:4512:20
Coauthor: Tian Ma (Sichuan University)
In this talk, we shall present three first principles and a few examples, demonstrating the symbiotic interplay between theoretical physics and advanced mathematics.
We start with a general principle that dynamic transitions of all dissipative systems can be classified into three categories: continuous, catastrophic and random. We shall illustrate this principle with a few examples in both equilibrium and nonequilibrium phase transitions, including the metastable oscillation mechanism of the El Nino Southern Oscillation (ENSO) and the existence of 3rdorder transitions beyond the Andrews critical point.
Then we present two basic principles: the principle of interaction dynamics (PID) and the principle of representation invariance (PRI), to study the nature's fundamental interactions/forces. Intuitively, PID takes the variation of the action functional under energymomentum conservation constraint. PRI requires that physical laws be independent of representations of the gauge groups. These two principles give rise to a unified field model for four interactions, which can be naturally decoupled to study individual interactions. With PID, for example, we derive new gravitational field equations with a vector field Φμ, which can be considered as a spin1 massless bosonic particle field. The field equations induce a natural duality between the graviton (spin2 massless bosonic particle) and this spin1 massless bosonic particle, leading to a unified theory for dark matter and dark energy. In addition, the PID offers a completely different and much simpler way of introducing Higgs fields.
20131030T12:33:47+00:00
2251
1588441
true
16x9
false
no

Inviscid Limits for the Stochastic Navier Stokes Equations and Related Systems
ucs_sms_1580157_1591207
http://sms.cam.ac.uk/media/1591207
Inviscid Limits for the Stochastic Navier Stokes Equations and Related Systems
GlattHoltz, N (Virginia Polytechnic Institute and State University)
Thursday 31 October 2013, 10:1010:45
Mon, 04 Nov 2013 10:05:02 +0000
Isaac Newton Institute
GlattHoltz, N
542c555c7581956b82ea58953fe96388
7b1635eec00f16264b5bd9d3d94f9353
ba96fcaf97833c6a4f45b24613433ff7
0205ced9fd4a3077328c9889da67737d
GlattHoltz, N (Virginia Polytechnic Institute and State University)
Thursday...
GlattHoltz, N (Virginia Polytechnic Institute and State University)
Thursday 31 October 2013, 10:1010:45
Cambridge University
2348
http://sms.cam.ac.uk/media/1591207
Inviscid Limits for the Stochastic Navier Stokes Equations and Related Systems
GlattHoltz, N (Virginia Polytechnic Institute and State University)
Thursday 31 October 2013, 10:1010:45
One of the original motivations for the development of stochastic partial differential equations traces it's origins to the study of turbulence. In particular, invariant measures provide a canonical mathematical object connecting the basic equations of fluid dynamics to the statistical properties of turbulent flows. In this talk we discuss some recent results concerning inviscid limits in this class of measures for the stochastic NavierStokes equations and other related systems arising in geophysical and numerical settings. This is joint work with Peter Constantin, Vladimir Sverak and Vlad Vicol.
20131104T10:05:41+00:00
2348
1591207
true
16x9
false
no

Kinetic energy dissipation and the stability of stationary turbulent flows
ucs_sms_1580157_1591200
http://sms.cam.ac.uk/media/1591200
Kinetic energy dissipation and the stability of stationary turbulent flows
Dewar, RC (Australian National University)
Thursday 31 October 2013, 09:3510:10
Mon, 04 Nov 2013 09:53:44 +0000
Isaac Newton Institute
Dewar, RC
c8341a326a95353e85ad35d778f7c420
3ee84d9ed5784e9282f668bc6383d505
ac87b676502f4f4e50e0f6182a076317
9be4a74aa84d2eedc840dc03995d3a19
Dewar, RC (Australian National University)
Thursday 31 October 2013,...
Dewar, RC (Australian National University)
Thursday 31 October 2013, 09:3510:10
Cambridge University
2231
http://sms.cam.ac.uk/media/1591200
Kinetic energy dissipation and the stability of stationary turbulent flows
Dewar, RC (Australian National University)
Thursday 31 October 2013, 09:3510:10
Variational principles of fluid turbulence offer an attractive alternative to numerical solution of the NavierStokes equation, especially for global climate studies. I discuss the principle (MaxD) that certain stationary turbulent flows maximize the rate of kinetic energy dissipation of the mean flow. Following its conjecture as an organizational principle for atmospheric circulation [1], MaxD has gained numerical support from global climate model simulations [2]. MaxD has also been derived for turbulent shear flow in a channel from considerations of dynamic stability, and yields realistic predictions for the mean velocity profile at all Reynolds numbers [3]. Further theoretical support for MaxD in channel flow has emerged from the statistical principle of maximum entropy [4]. Tying these threads together may lead to a clearer understanding of the theoretical basis and range of validity of MaxD for global climate studies. I outline possible approaches to doing this.
[1] Lorenz EN (1955) Generation of available potential energy and the intensity of the general circulation. Scientific Report No. 1, UCLA Large Scale Synoptic Processes Project.
[2] Pascale S, Gregory JM, Ambaum MHP, Tailleux R (2012) A parametric sensitivity study of entropy production and kinetic energy dissipation using the FAMOUS AOGCM. Clim. Dyn. 38, 12111227 and references therein.
[3] Malkus WVR (2003) Borders of disorders: in turbulent channel flow. J. Fluid Mech. 489, 185198.
[4] Dewar RC, Maritan A (2013) A theoretical basis for maximum entropy production. In Beyond the Second Law: Entropy Production and Nonequilibrium Systems (eds. RC Dewar, CH Lineweaver, RK Niven, K RegenauerLieb), Springer, in press.
20131104T09:55:27+00:00
2231
1591200
true
16x9
false
no

Lagrangian solutions for semigeostrophic system in physical space
ucs_sms_1580157_1612411
http://sms.cam.ac.uk/media/1612411
Lagrangian solutions for semigeostrophic system in physical space
Feldman, M (University of WisconsinMadison)
Thursday 05 December 2013, 10:1511:00
Mon, 09 Dec 2013 12:59:41 +0000
Isaac Newton Institute
Feldman, M
5dae401a064bf79a7c00bff82d17dbfe
d62e0ccaa2004585cf302f88f65cb4e4
fc41218b573f69b2a4dcb57f8d5290d6
7396a433412701aad7649cd3e444619d
Feldman, M (University of WisconsinMadison)
Thursday 05 December 2013,...
Feldman, M (University of WisconsinMadison)
Thursday 05 December 2013, 10:1511:00
Cambridge University
3478
http://sms.cam.ac.uk/media/1612411
Lagrangian solutions for semigeostrophic system in physical space
Feldman, M (University of WisconsinMadison)
Thursday 05 December 2013, 10:1511:00
Coauthor: Adrian Tudorascu
In this introductory talk, we review results on existence of solutions to semigeostrophic system in physical and dual spaces. In particular, we show that Lagrangian solutions in physical space can be constructed for initial data satisfying a strict convexity condition. We also briefly discuss the recent joint work with A. Tudorascu, in which we relax the notion of Lagrangian solution to obtain existence for all convex initial data in physical space.
20131209T12:59:41+00:00
3478
1612411
true
16x9
false
no

Largescale tropical atmospheric dynamics: asymptotic nondivergence?
ucs_sms_1580157_1615668
http://sms.cam.ac.uk/media/1615668
Largescale tropical atmospheric dynamics: asymptotic nondivergence?
Yano, JI (Meteo France)
Tuesday 10 December 2013, 11:0012:00
Fri, 13 Dec 2013 15:42:35 +0000
Isaac Newton Institute
Yano, JI
428f61de055dac998c451f9571925da6
e95e5d3fb8edbd0d2d333a3df77e055a
b2ea8afc6dac0dfec8bfe482a4bfb714
e38f9696f783ced0b87ca99c1a36c2a0
Yano, JI (Meteo France)
Tuesday 10 December 2013, 11:0012:00
Yano, JI (Meteo France)
Tuesday 10 December 2013, 11:0012:00
Cambridge University
3577
http://sms.cam.ac.uk/media/1615668
Largescale tropical atmospheric dynamics: asymptotic nondivergence?
Yano, JI (Meteo France)
Tuesday 10 December 2013, 11:0012:00
20131213T15:42:36+00:00
3577
1615668
true
16x9
false
no

Mathematical analysis of equatorial waves
ucs_sms_1580157_1594744
http://sms.cam.ac.uk/media/1594744
Mathematical analysis of equatorial waves
Gallagher, I (Université Paris 7  DenisDiderot)
Wednesday 06 November 2013, 15:0016:00
Fri, 08 Nov 2013 12:19:22 +0000
Isaac Newton Institute
Gallagher, I
b58dc47516629245d2541b8880c0e883
7b91c9640fb01284aaf00f3f9e8bf719
5b61802098a0fbfa9350d8d5400a5009
4237dd8af8de27d872a96eb23ef2d0d6
Gallagher, I (Université Paris 7  DenisDiderot)
Wednesday 06 November 2013,...
Gallagher, I (Université Paris 7  DenisDiderot)
Wednesday 06 November 2013, 15:0016:00
Cambridge University
2711
http://sms.cam.ac.uk/media/1594744
Mathematical analysis of equatorial waves
Gallagher, I (Université Paris 7  DenisDiderot)
Wednesday 06 November 2013, 15:0016:00
20131108T12:19:22+00:00
2711
1594744
true
16x9
false
no

Mathematical Study of Certain Geophysical Models: Global Regularity and Finitetime Blowup Results
ucs_sms_1580157_1610846
http://sms.cam.ac.uk/media/1610846
Mathematical Study of Certain Geophysical Models: Global Regularity and Finitetime Blowup Results
Titi, E (UC, Irvine and Weizmann Institute of Science)
Tuesday 03 December 2013, 09:1510:15
Fri, 06 Dec 2013 16:39:55 +0000
Isaac Newton Institute
Titi, E
e1879b98e5ce93c4909cfbaae57ffc63
5c919b136f4201ae99e1159e32a12603
63150a5ebf2e4e4f105eb52c52855dce
8f94808ed96c32443944039b9119cfaa
Titi, E (UC, Irvine and Weizmann Institute of Science)
Tuesday 03 December...
Titi, E (UC, Irvine and Weizmann Institute of Science)
Tuesday 03 December 2013, 09:1510:15
Cambridge University
3660
http://sms.cam.ac.uk/media/1610846
Mathematical Study of Certain Geophysical Models: Global Regularity and Finitetime Blowup Results
Titi, E (UC, Irvine and Weizmann Institute of Science)
Tuesday 03 December 2013, 09:1510:15
The basic problem faced in geophysical uid dynamics is that a mathematical description based only on fundamental physical principles, the socalled the \Primitive Equations", is often prohibitively expensive computationally, and hard to study analytically. In this talk I will discuss the main obstacles in proving the global regularity for the threedimensional NavierStokes equations and their geophysical counterparts. However, taking advantage of certain geophysical balances and situations, such as geostrophic balance and the shallowness of the ocean and atmosphere, geophysicists derive more simpli ed and manageable models which are easier to study analytically. In particular, I will present the global wellposedness for the threedimensional Benard convection problem in porous media, and the global regularity for a threedimensional viscous planetary geostrophic models. Even though the primitive equations look as if they are more dicult to study analytically than the threedimensional NavierStokes equations I will show, on the one hand, that the viscous primitive equations have a unique global (in time) regular solution for all initial data. On the other hand, I will show that in the nonviscous (inviscid) case there is a oneparameter family of initial data for which the corresponding smooth solutions develop nitetime singularities (blowup).
20131206T16:39:56+00:00
3660
1610846
true
16x9
false
no

Modelling the interactions of nearinertial waves and vortical motion in the ocean
ucs_sms_1580157_1610867
http://sms.cam.ac.uk/media/1610867
Modelling the interactions of nearinertial waves and vortical motion in the ocean
Vanneste, J (University of Edinburgh)
Tuesday 03 December 2013, 14:4515:30
Fri, 06 Dec 2013 16:56:10 +0000
Isaac Newton Institute
Vanneste, J
48262f23f9e5e8812ec7a6a6317ec6b4
dc0da10549fa3bd80ad5e64d7625f8ea
9febafcd4089833a19086cf536e2abbb
2e8fbf8fc79f8c164f86b078e1bcc8e6
Vanneste, J (University of Edinburgh)
Tuesday 03 December 2013, 14:4515:30
Vanneste, J (University of Edinburgh)
Tuesday 03 December 2013, 14:4515:30
Cambridge University
3103
http://sms.cam.ac.uk/media/1610867
Modelling the interactions of nearinertial waves and vortical motion in the ocean
Vanneste, J (University of Edinburgh)
Tuesday 03 December 2013, 14:4515:30
Coauthor: Eric Danioux (University of Edinburgh)
Wind forcing of the ocean generates a spectrum of inertiagravity waves that is sharply peaked near the local inertial (or Coriolis) frequency. The corresponding nearinertial waves (NIWs) make a dominant contribution to the vertical velocity and vertical shear in the ocean; they therefore play an important role for mixing, biological productivity, pollutant dispersion and, arguably, the thermohaline circulation. An asymptotic model proposed by Young and Ben Jelloul describes the slow evolution of NIWs that results from weak dispersion and from their interactions with the quasitwodimensional vortical motion. We derive this YBJ model by applying a form of Whitham averaging to the variational formulation of the primitive equations for a rotating stratified fluid. This provides a direct route to the YBJ equation and elucidates its variational structure and conservation laws. We then consider the effect of turbulent vortical motion (modelled as a homogeneous random field) of a scale similar to that of the waves. Specifically, we derive a transport equation for NIWs that describes their scattering by the vortical motion and show how this scattering leads to an isotropization of the NIW field. Direct numerical simulations of the YBJ equations are used to test the predictions of the transport equation. Possible models of the twoway coupling between NIWs and vortical motion are also discussed.
20131206T16:56:10+00:00
3103
1610867
true
16x9
false
no

MongeAmpère equations: geometry, invariants, and applications in 3D meteorological models
ucs_sms_1580157_1614586
http://sms.cam.ac.uk/media/1614586
MongeAmpère equations: geometry, invariants, and applications in 3D meteorological models
Rubtsov, V (Université d'Angers)
Friday 06 December 2013, 11:4512:30
Fri, 13 Dec 2013 10:33:42 +0000
Isaac Newton Institute
Rubtsov, V
4209ddc1b8ec0ba35f12b09d6ef675c6
8b4a37e9f527ce3b2d5c358b39780913
dd6766dbb968aa3b6e2f3fbf5d62dcb3
d520725797860fc2bd0934ef3e94b5d1
Rubtsov, V (Université d'Angers)
Friday 06 December 2013, 11:4512:30
Rubtsov, V (Université d'Angers)
Friday 06 December 2013, 11:4512:30
Cambridge University
2872
http://sms.cam.ac.uk/media/1614586
MongeAmpère equations: geometry, invariants, and applications in 3D meteorological models
Rubtsov, V (Université d'Angers)
Friday 06 December 2013, 11:4512:30
I describe a symplectic geometric approach to MongeAmpère equations, discuss some classical and modern geometric structures related to this class of nonlinear equations, their invariants and their role in 3D meteorological models. My talk is based on joint works with B. Banos and I . Roulstone.
20131213T10:33:42+00:00
2872
1614586
true
16x9
false
no

NavierStokes equations on a rotating sphere
ucs_sms_1580157_1612284
http://sms.cam.ac.uk/media/1612284
NavierStokes equations on a rotating sphere
Wirosoetisno, D (Durham University)
Wednesday 04 December 2013, 14:0014:45
Mon, 09 Dec 2013 12:12:55 +0000
Isaac Newton Institute
Wirosoetisno, D
dc9a46e87066ccee454ec51aab1dd711
df89e89a2618253f583e423ae89169a0
62577497a6426ddc13ebe3b4ba77b635
b07a9b1bf5a4c3cee23b24339dde05aa
Wirosoetisno, D (Durham University)
Wednesday 04 December 2013, 14:0014:45
Wirosoetisno, D (Durham University)
Wednesday 04 December 2013, 14:0014:45
Cambridge University
2653
http://sms.cam.ac.uk/media/1612284
NavierStokes equations on a rotating sphere
Wirosoetisno, D (Durham University)
Wednesday 04 December 2013, 14:0014:45
We showed that, as the rotation rate 1/ϵ increases, the solution of the 2d NavierStokes equations on a rotating sphere becomes zonal, in the sense that the nonzonal component of the energy becomes bounded by ϵ . This is obtained by estimating nearresonant interactions in the nonlinear term. As a consequence, the global attractor reduces to a single stable steady state when the rotation is fast enough (but still finite).
20131209T12:12:55+00:00
2653
1612284
true
16x9
false
no

Noise, Fluctuation, and Response in Geophysical Fluid Dynamics
ucs_sms_1580157_1591750
http://sms.cam.ac.uk/media/1591750
Noise, Fluctuation, and Response in Geophysical Fluid Dynamics
Lucarini, V (Universität Hamburg/University of Reading)
Friday 01 November 2013, 11:4512:20
Mon, 04 Nov 2013 11:51:44 +0000
Isaac Newton Institute
Lucarini, V
a1c082508445de47f482f1d12cffccbb
0e42180761b5bbf8f85f6d0d8eb898cc
62ce8022ffdc926b046f831393dc82c1
668d1d55d09c21505880504d1f384667
Lucarini, V (Universität Hamburg/University of Reading)
Friday 01 November...
Lucarini, V (Universität Hamburg/University of Reading)
Friday 01 November 2013, 11:4512:20
Cambridge University
1779
http://sms.cam.ac.uk/media/1591750
Noise, Fluctuation, and Response in Geophysical Fluid Dynamics
Lucarini, V (Universität Hamburg/University of Reading)
Friday 01 November 2013, 11:4512:20
Response theory provides formidable methods for addressing many problems in statistical mechanics. Recently, it has been proposed as a gateway for various challenges in geophysical fluid dynamics, such as the provision of a rigorous conceptual framework for computing climate response to a variety of forcings and for deriving effective equations for coarsegrained variables, thus paving the way for constructing accurate parametrization of unresolved processes in numerical models. In this contribution, we first would like to present some new results showing how one can use response theory to compute the impact of adding stochastic forcing to deterministic chaotic systems. Then, we will discuss the applicability of the fluctuationdissipation theorem in the context of nonequilibrium systems, focusing on the role played by the choice of observable. Finally, we will present some applications of response theory in geophysical fluid dynamical systems, ranging from loworder models such as the Lorenz 63 and Lorenz 96 models to General Circulation Models of the atmosphere.
20131104T11:52:21+00:00
1779
1591750
true
16x9
false
no

Nonequilibrium response, relaxation and the tmixing condition
ucs_sms_1580157_1606710
http://sms.cam.ac.uk/media/1606710
Nonequilibrium response, relaxation and the tmixing condition
Rondoni, L (Politecnico di Torino)
Tuesday 26 November 2013, 11:0012:00
Fri, 29 Nov 2013 10:47:15 +0000
Isaac Newton Institute
Rondoni, L
3c25038715ff67e30b79be70521d72b8
8352873b8cbd2a09c475fb9465609d33
2d5590f4ab6d0394d2bf864cb6d6e33d
ca199a959f589516f6273070092a4b31
Rondoni, L (Politecnico di Torino)
Tuesday 26 November 2013, 11:0012:00
Rondoni, L (Politecnico di Torino)
Tuesday 26 November 2013, 11:0012:00
Cambridge University
3780
http://sms.cam.ac.uk/media/1606710
Nonequilibrium response, relaxation and the tmixing condition
Rondoni, L (Politecnico di Torino)
Tuesday 26 November 2013, 11:0012:00
Twenty years ago a relation was proposed by Evans, Cohen and Morriss, which has been since known as Fluctuation Relation. This relation was initially intended to quantify the relative probability of positive and negative energy dissipation rates in nonequilibrium steady states. Later, it developed in many steady state as well transient relations. The search for the minimal ingredients which allow such steady state fluctuation relations to hold led to the formulation of the tmixing condition. This condition, similarly to the standard mixing condition, requires a certain decay of correlations, but different from that concerning standard mixing. We illustrate how the notion of tmixing arose in the context of fluctuation relations, and we compare it with standard mixing properties. Further, we note that besides yielding the fluctuation relations for dissipative, time reversal invariant deterministic systems, without need to explicitly invoke special properties for the phase space invariant measures, tmixing leads to a number of other results. We will discuss, in particular, those concerning relaxation to equilibrium or nonequilibrium stationary states and those concerning a general GreenKubolike response formula, which may be applied arbitrarily far from equilibrium to large as well as small systems (with correspondingly different meanings).
20131129T10:47:15+00:00
3780
1606710
true
16x9
false
no

Nonequilibrium statistical mechanics approach to turbulence
ucs_sms_1580157_1648290
http://sms.cam.ac.uk/media/1648290
Nonequilibrium statistical mechanics approach to turbulence
Beck, C (Queen Mary, University of London)
Wednesday 18 December 2013, 11:0012:00
Mon, 03 Feb 2014 15:49:49 +0000
Isaac Newton Institute
Beck, C
f4d799614ffa6c61426a5b3ce46f4b5f
e5dd866a52d80f612e1b538103bca207
f936ca2bc51c9b523bab187886012f21
9778bc1fc9808d7520601d30ce47f492
Beck, C (Queen Mary, University of London)
Wednesday 18 December 2013,...
Beck, C (Queen Mary, University of London)
Wednesday 18 December 2013, 11:0012:00
Cambridge University
4140
http://sms.cam.ac.uk/media/1648290
Nonequilibrium statistical mechanics approach to turbulence
Beck, C (Queen Mary, University of London)
Wednesday 18 December 2013, 11:0012:00
I will present an overview how superstatistical techniques (a method from nonequilbrium statistical mechanics) can be successfully used to model the statistical properties of turbulent flows. Examples treated are classical turbulence, quantum turbulence, environmental turbulence (wind gusts) and, if time remains, dark matter turbulence.
20140203T15:49:49+00:00
4140
1648290
true
16x9
false
no

Nonequilibrium statistical mechanics of climate variability: modelling issues and applications to data assimilation techniques
ucs_sms_1580157_1591759
http://sms.cam.ac.uk/media/1591759
Nonequilibrium statistical mechanics of climate variability: modelling issues and applications to data assimilation techniques
VandenEijnden, E (Courant Institute of Mathematical Sciences)
Friday 01 November 2013, 12:2012:55
Mon, 04 Nov 2013 11:55:56 +0000
Isaac Newton Institute
VandenEijnden, E
ccad637f5723a520ac8adabec037864e
27236406f91a3f4fd48153e38ad14aef
4a1e1acf8f0baa7b7c9f48d9d8d92a91
a410a7b6cb37db56897a00ca674580cb
VandenEijnden, E (Courant Institute of Mathematical Sciences)
Friday 01...
VandenEijnden, E (Courant Institute of Mathematical Sciences)
Friday 01 November 2013, 12:2012:55
Cambridge University
2416
http://sms.cam.ac.uk/media/1591759
Nonequilibrium statistical mechanics of climate variability: modelling issues and applications to data assimilation techniques
VandenEijnden, E (Courant Institute of Mathematical Sciences)
Friday 01 November 2013, 12:2012:55
Stochastic models and computational tools for the study of transitions between different metastable states (or regimes) in climate system are discussed using the barotropic quasigeostrophic (QG) equation as a test case. Specifically, a stochastic partial differential equation (SPDE) is obtained by adding appropriate forcing and damping terms to the QG equation to make this equation dynamically consistent with the predictions of equilibrium statistical mechanics, while allowing to study nonequilibrium phenomena such as transitions between different regimes. In the small noise regime, the most likely states of the invariant measure for this SPDE coincide with the selective decay states and we establish conditions under which these states are not unique, implying the existence of different climate regimes. We also analyze the mechanism and rate of the dynamical transitions between these regimes by computing the most likely paths connecting them. Finally we will discuss how the se results can be used in the context of data assimilation procedure based on Kalman or ensemble filters to improve the efficiency of these methods in the presence of regime shifts.
20131104T11:56:24+00:00
2416
1591759
true
16x9
false
no

Nonequilibrium: from heat conduction, to turbulence (to life): Rothschild Distinguished Visiting Fellow lecture
ucs_sms_1580157_1598914
http://sms.cam.ac.uk/media/1598914
Nonequilibrium: from heat conduction, to turbulence (to life): Rothschild Distinguished Visiting Fellow lecture
Ruelle, D (IHES)
Tuesday 12 November 2013, 16:0017:00
Fri, 15 Nov 2013 09:54:00 +0000
Isaac Newton Institute
Ruelle, D
60ca94b9831dafcc6eb8d012e1b957ac
4c8135d52f0917a6dad3020fffa37e50
4910b8b19b6415bed371e29dc76c060f
5c2b1d0d24a5671fa97f0d83bb4dc5b8
Ruelle, D (IHES)
Tuesday 12 November 2013, 16:0017:00
Ruelle, D (IHES)
Tuesday 12 November 2013, 16:0017:00
Cambridge University
3960
http://sms.cam.ac.uk/media/1598914
Nonequilibrium: from heat conduction, to turbulence (to life): Rothschild Distinguished Visiting Fellow lecture
Ruelle, D (IHES)
Tuesday 12 November 2013, 16:0017:00
20131115T09:54:00+00:00
3960
1598914
true
16x9
false
no

On bounded velocity/bounded vorticity solutions to the incompressible 2D Euler equations
ucs_sms_1580157_1603031
http://sms.cam.ac.uk/media/1603031
On bounded velocity/bounded vorticity solutions to the incompressible 2D Euler equations
Nussenzveig Lopes, HJ (Universidade Federal do Rio de Janeiro (UFRJ))
Wednesday 20 November 2013, 10:0011:00
Fri, 22 Nov 2013 14:16:01 +0000
Isaac Newton Institute
Nussenzveig Lopes, HJ
7ac77e9c59eacedeb390c7c0d30a8884
dd3e19d408e292574beac2a6f1827805
2b16b36550379d32a5e0b9ea3e60aa3d
f598bb4c6bbafed7c44f56ab9859f182
Nussenzveig Lopes, HJ (Universidade Federal do Rio de Janeiro...
Nussenzveig Lopes, HJ (Universidade Federal do Rio de Janeiro (UFRJ))
Wednesday 20 November 2013, 10:0011:00
Cambridge University
2923
http://sms.cam.ac.uk/media/1603031
On bounded velocity/bounded vorticity solutions to the incompressible 2D Euler equations
Nussenzveig Lopes, HJ (Universidade Federal do Rio de Janeiro (UFRJ))
Wednesday 20 November 2013, 10:0011:00
In 1963 V. I. Yudovich proved the existence and uniqueness of weak solutions of the incompressible 2D Euler equations in a bounded domain assuming that the vorticity, which is the curl of velocity, is bounded. This result was later extended by A. Majda to vorticities which are bounded and integrable in the full plane. Further extensions of this result have been obtained, yet always assuming some decay of vorticity at infi nity. In a short note in 1995, Philippe Serfati gave an incomplete, yet brilliant, proof of existence and uniqueness of solutions to the 2D Euler equations in the whole plane when the initial vorticity and initial velocity are bounded, without the need for decay at in finity. In this talk I will report on work aimed at completing and extending Serfati's result to flows in a domain exterior to an obstacle. This is joint work with David Ambrose (Drexel University), James P. Kelliher (University of California, Riverside) and Milton C. Lopes Filho (Federal University of Rio de Janeiro).
20131122T14:16:01+00:00
2923
1603031
true
16x9
false
no

On the use of Ruelle's formalism in response theory
ucs_sms_1580157_1589182
http://sms.cam.ac.uk/media/1589182
On the use of Ruelle's formalism in response theory
Colangeli, M (Politecnico di Torino)
Wednesday 30 October 2013, 14:1514:50
Thu, 31 Oct 2013 12:58:01 +0000
Isaac Newton Institute
Colangeli, M
8a64cb6a83100c37c15a87bcb8d85d09
62616d4d3599d5d2efb110507aade83b
17a7d9de50ac1f2114f15fcdde3d1d55
0ba5587ce2f6890688377aa0e8a046ea
Colangeli, M (Politecnico di Torino)
Wednesday 30 October 2013, 14:1514:50
Colangeli, M (Politecnico di Torino)
Wednesday 30 October 2013, 14:1514:50
Cambridge University
2130
http://sms.cam.ac.uk/media/1589182
On the use of Ruelle's formalism in response theory
Colangeli, M (Politecnico di Torino)
Wednesday 30 October 2013, 14:1514:50
We use Ruelle’s formalism to express the response of a generic observable to a certain perturbation in terms of correlation functions computed with respect to the unperturbed invariant measure, for deterministic as well as stochastic dynamics. We discuss the onset of two relevant terms for the entropy production, comment on the Hamiltonian version of the resulting formulae and also propose a connection with similar results, reported in the literature, allowing to extend the FluctuationDissipation formalism to nonequilibrium steady states.
20131031T12:58:31+00:00
2130
1589182
true
16x9
false
no

On the vortexwave system
ucs_sms_1580157_1598945
http://sms.cam.ac.uk/media/1598945
On the vortexwave system
da Costa Lopes Filho, M (Universidade Federal do Rio de Janeiro (UFRJ))
Wednesday 13 November 2013, 10:0011:00
Fri, 15 Nov 2013 11:59:48 +0000
Isaac Newton Institute
da Costa Lopes Filho, M
0ea6fff9ebe7824c3e2df3471e0947d8
9ea5edc426bc355d779719d866558b10
5aba76748d1e633f19821b4fbf182ff6
a9567aee930b7d59c7650b3c543e7562
da Costa Lopes Filho, M (Universidade Federal do Rio de Janeiro...
da Costa Lopes Filho, M (Universidade Federal do Rio de Janeiro (UFRJ))
Wednesday 13 November 2013, 10:0011:00
Cambridge University
3247
http://sms.cam.ac.uk/media/1598945
On the vortexwave system
da Costa Lopes Filho, M (Universidade Federal do Rio de Janeiro (UFRJ))
Wednesday 13 November 2013, 10:0011:00
The vortexwave system is the coupling of the 2D vorticity equation with the pointvortex system, and it is a model for the motion of sharply concentrated vórtices within a smooth(er) vorticity background. This system was introduced by Marchioro and Pulvirenti in 1991. In this talk we will give a fairly complete look at what is known and what is not known about this system.
20131115T11:59:48+00:00
3247
1598945
true
16x9
false
no

On thermodynamics of stationary states of diffusive systems
ucs_sms_1580157_1589147
http://sms.cam.ac.uk/media/1589147
On thermodynamics of stationary states of diffusive systems
JonaLasinio, G (Università degli Studi di Roma La Sapienza)
Wednesday 30 October 2013, 09:0009:35
Thu, 31 Oct 2013 12:36:20 +0000
Isaac Newton Institute
JonaLasinio, G
9093acc65a677503ee96edffa84a8a02
de1ddf5d6f9013a537f856dd3e64554e
42b909cb2b41cdc5e1307b5f423b9dfc
2d26fb2c6ab9afdab8be9b8e03876e53
JonaLasinio, G (Università degli Studi di Roma La Sapienza)
Wednesday 30...
JonaLasinio, G (Università degli Studi di Roma La Sapienza)
Wednesday 30 October 2013, 09:0009:35
Cambridge University
2456
http://sms.cam.ac.uk/media/1589147
On thermodynamics of stationary states of diffusive systems
JonaLasinio, G (Università degli Studi di Roma La Sapienza)
Wednesday 30 October 2013, 09:0009:35
Coauthors L. Bertini, A. De Sole, D. Gabrielli, C. Landim
Thermodynamic transformations connecting nonequilibrium stationary states have the peculiarity of dissipating, to keep the system out of equilibrium, an amount of energy which diverges for a quasi static transformation. By subtracting the divergent part one can define a renormalized work that satisfies a Clausius type inequality and with respect to which quasi static transformations are optimal. A different way of analyzing the energy balance and optimality criteria is to consider transformations over a long but finite time T developing the total work and the dissipated energy in powers of 1/T. The diverging terms cancel and one obtains relations among finite quantities.
20131031T12:37:02+00:00
2456
1589147
true
16x9
false
no

On Time Integration and the Use of Clebsch Variables in Shallow Water Equations
ucs_sms_1580157_1618129
http://sms.cam.ac.uk/media/1618129
On Time Integration and the Use of Clebsch Variables in Shallow Water Equations
Bokhove, O (University of Leeds)
Friday 06 December 2013, 11:0011:45
Tue, 17 Dec 2013 09:29:17 +0000
Isaac Newton Institute
Bokhove, O
2adfc51ca3e284030bf607e61b134252
810f708239472ad229b3e5080469c6c6
f5a7253656e0ec7d77efee52e1a104ee
0fcc4021880adcc4e0cdbcc3a01ac028
Bokhove, O (University of Leeds)
Friday 06 December 2013, 11:0011:45
Bokhove, O (University of Leeds)
Friday 06 December 2013, 11:0011:45
Cambridge University
2874
http://sms.cam.ac.uk/media/1618129
On Time Integration and the Use of Clebsch Variables in Shallow Water Equations
Bokhove, O (University of Leeds)
Friday 06 December 2013, 11:0011:45
Two topics will be covered in this lecture. The shallow water equations will be used as a test bed to introduce the ideas.
(i) For forced variational systems such as the potential flow shallow water wave equations, variational and symplectic time integrators will be extended using a new finite element approach. Here, a standard variational finite element discretization will be applied in space.
(ii) The shallow water equations formulated in terms of Clebsch variables will be discussed. The advantage of Clebsch variables is that they lead to canonical Hamilton's equations for shallow water dynamics, in the Eulerian framework. A disadvantage is that the the system, is less compactly expressed in comparison to the usual formulation in terms of the velocity and fluid depth. I will make a link between a symmetry in the Hamiltonian and the associated mass weighted potential vorticity conservation law, also within the Eulerian framework. This will be done in two dimensions (2D) and in a quasi2D symmetric form.
20131217T09:29:17+00:00
2874
1618129
true
16x9
false
no

Optimal location problems with routing cost
ucs_sms_1580157_1591706
http://sms.cam.ac.uk/media/1591706
Optimal location problems with routing cost
Buttazzo, GM (Università di Pisa)
Friday 01 November 2013, 09:3510:10
Mon, 04 Nov 2013 11:48:34 +0000
Isaac Newton Institute
Buttazzo, GM
933a75feb36d4ab16a9bbe328f732c41
3d75b11b7c8284332638230663eb4129
02a7320d23c9dbc446a5613dba2056cd
fcc9072e36ccc0d14ebe1069506aa87a
Buttazzo, GM (Università di Pisa)
Friday 01 November 2013, 09:3510:10
Buttazzo, GM (Università di Pisa)
Friday 01 November 2013, 09:3510:10
Cambridge University
1895
http://sms.cam.ac.uk/media/1591706
Optimal location problems with routing cost
Buttazzo, GM (Università di Pisa)
Friday 01 November 2013, 09:3510:10
Coauthors: Serena Guarino (University of Pisa (Italy)), Fabrizio Oliviero (University of Pisa (Italy))
A model problem for the location of a given number N of points in a given region Ω and with a given resources density ρ(x) is considered. The main difference between the usual location problems and the present one is that in addition to the location cost an extra {\it routing cost} is considered, that takes into account the fact that the resources have to travel between the locations on a pointtopoint basis. The limit problem as N→∞ is characterized and some applications to airfreight systems are shown.
20131104T11:49:09+00:00
1895
1591706
true
16x9
false
no

Paleoclimatic time series: statistics and dynamics
ucs_sms_1580157_1588427
http://sms.cam.ac.uk/media/1588427
Paleoclimatic time series: statistics and dynamics
Imkeller, P (HumboldtUniversität zu Berlin)
Tuesday 29 October 2013, 10:1010:45
Wed, 30 Oct 2013 12:19:12 +0000
Isaac Newton Institute
Imkeller, P
964519ec35ea088278736b5dec4c434f
9fbcf1ea2a048174e326573fc4afe6ca
eb5af40aa343ec087a0dd0144732ae93
662e634fabf338a21198fc030651cabf
Imkeller, P (HumboldtUniversität zu Berlin)
Tuesday 29 October 2013,...
Imkeller, P (HumboldtUniversität zu Berlin)
Tuesday 29 October 2013, 10:1010:45
Cambridge University
2240
http://sms.cam.ac.uk/media/1588427
Paleoclimatic time series: statistics and dynamics
Imkeller, P (HumboldtUniversität zu Berlin)
Tuesday 29 October 2013, 10:1010:45
Coauthors: Arnaud Debussche (ENS Cachan), Jan Gairing (HU Berlin), Claudia Hein (HU Berlin), Michael Högele (U Potsdam), Ilya Pavlyukevich (U Jena)
Dynamical systems of the reactiondiffusion type with small noise have been instrumental to explain basic features of the dynamics of paleoclimate data. For instance, a spectral analysis of Greenland ice time series performed at the end of the 1990s representing average temperatures during the last ice age suggest an α−stable noise component with an α∼1.75. We model the time series as a dynamical system perturbed by αstable noise, and develop an efficient testing method for the best fitting α. The method is based on the observed pvariation of the residuals of the time series, and their asymptotic αpstability established in local limit theorems.\par\smallskip
Generalizing the solution of this model selection problem, we are led to a class of reactiondiffusion equations with additive αstable L\'evy noise, a stochastic perturbation of the ChafeeInfante equation. We study exit and transition between metastable states of their solutions. Due to the heavytail nature of an αstable noise component, the results differ strongly from the well known case of purely Gaussian perturbations.
20131030T12:19:58+00:00
2240
1588427
true
16x9
false
no

Perturbations of the Lorentz Gas via Spectral Methods
ucs_sms_1580157_1598505
http://sms.cam.ac.uk/media/1598505
Perturbations of the Lorentz Gas via Spectral Methods
Demers, M (Fairfield University)
Tuesday 12 November 2013, 11:0012:00
Thu, 14 Nov 2013 16:16:51 +0000
Isaac Newton Institute
Demers, M
4a61e85a6959ad7a4a1a0fdcfe3e3d00
afb7c3714ddf40dc6c0c484648fb5005
34dae1b65d0b8e04c3b20f52d18b2750
85fe53eb9edb9b78f189fe4a20f019bf
Demers, M (Fairfield University)
Tuesday 12 November 2013, 11:0012:00
Demers, M (Fairfield University)
Tuesday 12 November 2013, 11:0012:00
Cambridge University
2787
http://sms.cam.ac.uk/media/1598505
Perturbations of the Lorentz Gas via Spectral Methods
Demers, M (Fairfield University)
Tuesday 12 November 2013, 11:0012:00
20131114T16:16:51+00:00
2787
1598505
true
16x9
false
no

Phase transitions and large deviations in geophysical fluid dynamics
ucs_sms_1580157_1591714
http://sms.cam.ac.uk/media/1591714
Phase transitions and large deviations in geophysical fluid dynamics
Bouchet, F (ENS  Lyon)
Friday 01 November 2013, 10:1010:45
Mon, 04 Nov 2013 11:54:39 +0000
Isaac Newton Institute
Bouchet, F
9db838616056b747fd934fec57f02f27
790d578bcfdc95df9516cd994826a4c1
be9e596bc28244174aedff69e97ca724
37b24fadea8ddad26d6c70ab452a6654
Bouchet, F (ENS  Lyon)
Friday 01 November 2013, 10:1010:45
Bouchet, F (ENS  Lyon)
Friday 01 November 2013, 10:1010:45
Cambridge University
2458
http://sms.cam.ac.uk/media/1591714
Phase transitions and large deviations in geophysical fluid dynamics
Bouchet, F (ENS  Lyon)
Friday 01 November 2013, 10:1010:45
Geophysical turbulent flows (atmosphere and climate dynamics, the Earth core dynamics) often undergo very rapid transitions. Those abrupt transitions change drastically the nature of the flow and are of paramount importance, for instance in climate. By contrast with most theoretical models of phase transitions, for turbulent flows it is difficult to characterize clearly the attractors (they are not simple fixed points of a deterministic dynamics or statistical equilibrium states) and the trajectories that lead to transitions from one attractor to the others.
I will review recent researches in this subject, including experimental and numerical studies of turbulent flows. Most of the talk will focus on theoretical works in the framework of the 2D stochastic quasigeostrophic NavierStokes equations, the quasigeostrophic equations, and the stochastic Vlasov equations. We will discuss predictions of phase transitions, validity of large deviation results of the FreidlinWentzell type, or more involved approaches when the FreidlinWentzell approach is not valid.
The results involve several works that have been done in collaborations with J. Laurie, M. Mathur, C. Nardini, E. Simonnet, J. Sommeria, T. Tangarife, H. Touchette, and O. Zaboronski.
20131104T11:55:09+00:00
2458
1591714
true
16x9
false
no

Predictability of extreme events in dynamical systems: A case study of the Lorenz 84 model
ucs_sms_1580157_1648283
http://sms.cam.ac.uk/media/1648283
Predictability of extreme events in dynamical systems: A case study of the Lorenz 84 model
Bodai, T (University of Hamburg)
Wednesday 18 December 2013, 10:0011:00
Mon, 03 Feb 2014 15:46:01 +0000
Isaac Newton Institute
Bodai, T
ee3cc4bb76e5e8caa4c04b7b156c6ff2
9006c8d19b53fce03ec68b2fbf85cbb6
812d67a7562a3d71991e9862d028d6e1
193ba0f390cef67c42230d2e6fae1597
Bodai, T (University of Hamburg)
Wednesday 18 December 2013, 10:0011:00
Bodai, T (University of Hamburg)
Wednesday 18 December 2013, 10:0011:00
Cambridge University
3600
http://sms.cam.ac.uk/media/1648283
Predictability of extreme events in dynamical systems: A case study of the Lorenz 84 model
Bodai, T (University of Hamburg)
Wednesday 18 December 2013, 10:0011:00
20140203T15:46:01+00:00
3600
1648283
true
16x9
false
no

Quantifying uncertainty and improving reducedorder predictions of partially observed turbulent dynamical systems
ucs_sms_1580157_1588448
http://sms.cam.ac.uk/media/1588448
Quantifying uncertainty and improving reducedorder predictions of partially observed turbulent dynamical systems
Branicki, M (New York University)
Tuesday 29 October 2013, 13:4014:15
Wed, 30 Oct 2013 12:35:30 +0000
Isaac Newton Institute
Branicki, M
c2065f628e2471e16f0715cd6efa0b9a
0966a09ec6a6306d5796a46de1d40bec
4ddaf6c91561761831a01d61d754c544
1d1e2ab72beb17ae1edb7adc7cc8d418
Branicki, M (New York University)
Tuesday 29 October 2013, 13:4014:15
Branicki, M (New York University)
Tuesday 29 October 2013, 13:4014:15
Cambridge University
2140
http://sms.cam.ac.uk/media/1588448
Quantifying uncertainty and improving reducedorder predictions of partially observed turbulent dynamical systems
Branicki, M (New York University)
Tuesday 29 October 2013, 13:4014:15
Coauthor: A. J. Majda (Courant Institute, NYU)
The issue of mitigating model error in reducedorder prediction of highdimensional dynamics is particularly important when dealing with turbulent geophysical systems with rough energy spectra and intermittency near the resolution cutoff of the corresponding numerical models. I will discuss a new framework which allows for informationtheoretic quantification of uncertainty and mitigation of model error in imperfect stochastic/statistical predictions of nonGaussian, multiscale dynamics. In particular, I will outline the utility of this framework in derivation of a sufficient condition for improving imperfect predictions via a popular but heuristic Multi Model Ensemble approach. Time permitting, the role and validity of 'fluctuationdissipation' arguments for improving imperfect predictions of externally perturbed nonautonomous turbulent systems will also be addressed.
20131030T12:36:03+00:00
2140
1588448
true
16x9
false
no

Rare events, negative measure dimensions and return time statistics
ucs_sms_1580157_1615661
http://sms.cam.ac.uk/media/1615661
Rare events, negative measure dimensions and return time statistics
Mantica, G (Center for nonlinear and Complex Systems, Universita' dell'Insubria)
Thursday 12 December 2013, 10:0011:00
Fri, 13 Dec 2013 15:39:32 +0000
Isaac Newton Institute
Mantica, G
0e8599e3c499ff7288512becd1526bf5
dab2c74227a3dfc81c8afea2c06ae357
44f4e981a89093f334a103cccfbc40e3
cc226d9ac56ce6345df54f0e1ba41ef6
Mantica, G (Center for nonlinear and Complex Systems, Universita'...
Mantica, G (Center for nonlinear and Complex Systems, Universita' dell'Insubria)
Thursday 12 December 2013, 10:0011:00
Cambridge University
3443
http://sms.cam.ac.uk/media/1615661
Rare events, negative measure dimensions and return time statistics
Mantica, G (Center for nonlinear and Complex Systems, Universita' dell'Insubria)
Thursday 12 December 2013, 10:0011:00
20131213T15:39:32+00:00
3443
1615661
true
16x9
false
no

Recent observations of mesoscale structures in intense cyclones
ucs_sms_1580157_1609045
http://sms.cam.ac.uk/media/1609045
Recent observations of mesoscale structures in intense cyclones
Methven, J (University of Reading)
Monday 02 December 2013, 11:3012:15
Tue, 03 Dec 2013 14:07:33 +0000
Isaac Newton Institute
Methven, J
395af95dfe883a849411f4373b898fd9
2ea8cf0e201a50964abf7ba904ba6521
d7044e65f3b165a4635fe691897165b5
30dff056c6fada0727db6fc0fea04ca7
Methven, J (University of Reading)
Monday 02 December 2013, 11:3012:15
Methven, J (University of Reading)
Monday 02 December 2013, 11:3012:15
Cambridge University
2798
http://sms.cam.ac.uk/media/1609045
Recent observations of mesoscale structures in intense cyclones
Methven, J (University of Reading)
Monday 02 December 2013, 11:3012:15
The impact of intense cyclones is often associated with coherent mesoscale structures embedded within them. Although the formation of cold fronts is to some extent described by semigeostrophic theory, the dynamics of many of these features are not well understood. For example, whether they could be described by a form balance appropriate on the mesoscale, or in the presence of nonconservative processes. Some recent detailed observations of cyclones and fronts are presented and some of the unknown aspects of their dynamics highlighted.
20131203T14:07:33+00:00
2798
1609045
true
16x9
false
no

Renormalized relaxed Lagrangian solutions for SG in physical space
ucs_sms_1580157_1613244
http://sms.cam.ac.uk/media/1613244
Renormalized relaxed Lagrangian solutions for SG in physical space
Tudorascu, A (West Virginia University)
Thursday 05 December 2013, 11:3012:15
Tue, 10 Dec 2013 09:41:52 +0000
Isaac Newton Institute
Tudorascu, A
760e936de631b7d044628ab231ee9305
c94d8671cc5a965b99229a567aa53ff2
45d108959ad8f7c2354c393aafaef263
666d3a979c83b21c0e05034c8255d2d0
Tudorascu, A (West Virginia University)
Thursday 05 December 2013, 11:3012:15
Tudorascu, A (West Virginia University)
Thursday 05 December 2013, 11:3012:15
Cambridge University
3247
http://sms.cam.ac.uk/media/1613244
Renormalized relaxed Lagrangian solutions for SG in physical space
Tudorascu, A (West Virginia University)
Thursday 05 December 2013, 11:3012:15
A new, relaxed notion of Lagrangian solutions for SG in physical space will be introduced. The main motivation is the search for physical space solutions in the case of singular data in dual space. Existence and a weak stability result will be proved, along with an energy conservation result which comes as a consequence of the renormalization property. This presentation is based on joint work with M. Feldman (U. WisconsinMadison).
20131210T09:41:52+00:00
3247
1613244
true
16x9
false
no

Rescaled vorticity moments in the 3D NavierStokes equations
ucs_sms_1580157_1609038
http://sms.cam.ac.uk/media/1609038
Rescaled vorticity moments in the 3D NavierStokes equations
Gibbon, J (Imperial College London)
Monday 02 December 2013, 10:1511:00
Tue, 03 Dec 2013 14:04:07 +0000
University of Cambridge
Rob Leonard
7f78daf0eecc9231c125f4559282e289
f013febf8483c0c9821d1280787879c0
b9e886faf8323122f347e7ab190246a4
88b48fc586fe5b360f21fbe192e7588c
Gibbon, J (Imperial College London)
Monday 02 December 2013, 10:1511:00
Gibbon, J (Imperial College London)
Monday 02 December 2013, 10:1511:00
Cambridge University
2544
http://sms.cam.ac.uk/media/1609038
Rescaled vorticity moments in the 3D NavierStokes equations
Gibbon, J (Imperial College London)
Monday 02 December 2013, 10:1511:00
Coauthors: D. D. Donzis (Texas A and M), A. Gupta (University of Rome Tor Vergata), R. M. Kerr (University of Warwick), R. Pandit (Indian Institute of Science Bangalore), D. Vincenzi (CNRS, Universite de Nice)
The issue of intermittency in numerical solutions of the 3D NavierStokes equations is addressed using a new set of variables whose evolution has been calculated through three sets of numerical simulations. These variables are defined on a periodic box [0,L]3 such that Dm(t)=(ϖ−10Ωm)αm where αm=2m/(4m−3) \& the set of frequencies Ωm for 1≤m≤∞ are defined by Ωm(t)=(L−3\I\boldmathω2mdV)1/2m\,; the fixed frequency ϖ0=νL−2. All three simulations unexpectedly show that the Dm are ordered for m=1,...,9 such that Dm+1<Dm. Moreover, the Dm squeeze together such that Dm+1/Dm↗1 as m increases. This regime is shown to connected to the depletion of nonlinearity. The first simulation is of very anisotropic decaying turbulence\,; the second pair is of decaying isotropic turbulence from random initial conditions \& of forced isotropic turbulence at constant Grashof number\,; the third 40963 simulation is of very high Reynolds number forced, stationary, isotropic turbulence.
20131203T14:04:08+00:00
2544
1609038
true
16x9
false
no

Resonant phenomena in the wave dynamics in the presence of boundaries in GFD
ucs_sms_1580157_1612396
http://sms.cam.ac.uk/media/1612396
Resonant phenomena in the wave dynamics in the presence of boundaries in GFD
Zeitlin, V (Laboratoire de Météorologie Dynamique (LMDENS))
Wednesday 04 December 2013, 16:0016:45
Mon, 09 Dec 2013 12:54:16 +0000
Isaac Newton Institute
Zeitlin, V
44aa9186065dd13e1278ac81c7590b93
09f8cd7d73540b4882eff3b1e85501be
a0eec1272c437dd8ef8e1c5ab420502e
f8b3ca459b38f804cf448991da0ccfe9
Zeitlin, V (Laboratoire de Météorologie Dynamique (LMDENS))
Wednesday 04...
Zeitlin, V (Laboratoire de Météorologie Dynamique (LMDENS))
Wednesday 04 December 2013, 16:0016:45
Cambridge University
2889
http://sms.cam.ac.uk/media/1612396
Resonant phenomena in the wave dynamics in the presence of boundaries in GFD
Zeitlin, V (Laboratoire de Météorologie Dynamique (LMDENS))
Wednesday 04 December 2013, 16:0016:45
Coauthor: Grigory Reznik (Int of Oceanography, Moscow)
I will be discussing resonant interactions of coastal and shelf waves with free inertiagravity waves and mean coastal currents in GFD.
20131209T12:54:16+00:00
2889
1612396
true
16x9
false
no

Rigorous computation of invariant measures and Lyapunov exponents
ucs_sms_1580157_1588420
http://sms.cam.ac.uk/media/1588420
Rigorous computation of invariant measures and Lyapunov exponents
Galatolo, S (Università di Pisa)
Tuesday 29 October 2013, 09:3510:10
Wed, 30 Oct 2013 12:10:12 +0000
Isaac Newton Institute
Galatolo, S
fea821b96ac57bf580557104515c5223
fa85ee9eae088c4921508c24502ef2c1
95c05d521d25b50fd71b6b0e9b62f02f
ebe6a83028a51aeb2c9390dd116e0bcf
Galatolo, S (Università di Pisa)
Tuesday 29 October 2013, 09:3510:10
Galatolo, S (Università di Pisa)
Tuesday 29 October 2013, 09:3510:10
Cambridge University
2051
http://sms.cam.ac.uk/media/1588420
Rigorous computation of invariant measures and Lyapunov exponents
Galatolo, S (Università di Pisa)
Tuesday 29 October 2013, 09:3510:10
Coauthor: Isaia Nisoli (Universitade Federal Rio de Janeiro)
We will consider the problem of computation of invariant measures and other aspects related to the statistical behavior of the dynamics up to certified errors.
In this way the output of a computation represent some rigorous quantitative estimation on the behavior of the dynamics under study, going towards more reliable tools for the simulation of dynamical models.
We will show some general approach which can be applied in several cases of systems having some hyperbolic behavior, including maps with indifferent fixed points.
Time permitting we will also consider a class piecewise hyperbolic maps related to the Lorenz attractor.
20131030T12:11:06+00:00
2051
1588420
true
16x9
false
no

Scaling, macro weather and the climate
ucs_sms_1580157_1594712
http://sms.cam.ac.uk/media/1594712
Scaling, macro weather and the climate
Lovejoy, S (McGill University)
Wednesday 06 November 2013, 11:0012:00
Fri, 08 Nov 2013 12:29:07 +0000
Isaac Newton Institute
Lovejoy, S
c0b8a721deae26cf6dade0431c4df2da
fa8b4c793d7d61947c55f11ddd8ad671
2de283df9ce383fc811dae6b53b76f9d
7d00510f398095fbd84cc3a0ed733bec
Lovejoy, S (McGill University)
Wednesday 06 November 2013, 11:0012:00
Lovejoy, S (McGill University)
Wednesday 06 November 2013, 11:0012:00
Cambridge University
3780
http://sms.cam.ac.uk/media/1594712
Scaling, macro weather and the climate
Lovejoy, S (McGill University)
Wednesday 06 November 2013, 11:0012:00
20131108T12:29:07+00:00
3780
1594712
true
16x9
false
no

Slice models
ucs_sms_1580157_1612260
http://sms.cam.ac.uk/media/1612260
Slice models
Holm, D (Imperial College London)
Wednesday 04 December 2013, 09:1510:15
Mon, 09 Dec 2013 11:51:29 +0000
Isaac Newton Institute
Holm, D
cd5c24ce60c5398ad2461cbe9ccb8826
fd8b15706c071fb1de8741062c5f4153
d88c84f73ac4ccf7b54f54801de68e16
8af00c92f6504741e0c9cd5585be09b4
Holm, D (Imperial College London)
Wednesday 04 December 2013, 09:1510:15
Holm, D (Imperial College London)
Wednesday 04 December 2013, 09:1510:15
Cambridge University
3095
http://sms.cam.ac.uk/media/1612260
Slice models
Holm, D (Imperial College London)
Wednesday 04 December 2013, 09:1510:15
Coauthor: Colin Cotter (Imperial College)
A variational framework is defined for vertical slice models with three dimensional velocity depending only on horizontal x and vertical z . The models that result from this framework are Hamiltonian, and have a KelvinNoether circulation theorem that results in a conserved potential vorticity in the slice geometry. These results are demonstrated for the incompressible EulerBoussinesq equations with a constant temperature gradient in the y direction (the EadyBoussinesq model), which is an idealised problem used to study the formation and subsequent evolution of weather fronts. We then introduce a new compressible extension of this model for testing compressible weather models running in a vertical slice configuration. (Joint work with CJ Cotter, Imperial College).
20131209T11:51:29+00:00
3095
1612260
true
16x9
false
no

Some basics in the asymptotic analysis of geophysical fluids
ucs_sms_1580157_1594719
http://sms.cam.ac.uk/media/1594719
Some basics in the asymptotic analysis of geophysical fluids
Gallagher, I (Université Paris 7  DenisDiderot)
Wednesday 06 November 2013, 14:0015:00
Fri, 08 Nov 2013 12:27:08 +0000
Isaac Newton Institute
Gallagher, I
aa9949962ca4be8a8d848edc0ad8a510
69999f5e3cba1662c28b61d1061d6ad4
5c2c82239000cf5f4d08b5ccacdbd917
c1457cee6185f63e5e71844d851923af
Gallagher, I (Université Paris 7  DenisDiderot)
Wednesday 06 November 2013,...
Gallagher, I (Université Paris 7  DenisDiderot)
Wednesday 06 November 2013, 14:0015:00
Cambridge University
3317
http://sms.cam.ac.uk/media/1594719
Some basics in the asymptotic analysis of geophysical fluids
Gallagher, I (Université Paris 7  DenisDiderot)
Wednesday 06 November 2013, 14:0015:00
20131108T12:27:08+00:00
3317
1594719
true
16x9
false
no

Some statistical properties for random and sequential dynamical systems
ucs_sms_1580157_1606703
http://sms.cam.ac.uk/media/1606703
Some statistical properties for random and sequential dynamical systems
Aimino, R (Centre de Physique Théorique, Marseille)
Tuesday 26 November 2013, 10:0011:00
Fri, 29 Nov 2013 10:42:37 +0000
Isaac Newton Institute
Aimino, R
3296f08103c0db0207e8e7a664421796
7cd34a52062589042bfa353a70e2d8f8
4605edcf9013852d664d538fea96398e
0c56e6a6ca11151f29b59f9676fc5171
Aimino, R (Centre de Physique Théorique, Marseille)
Tuesday 26 November 2013,...
Aimino, R (Centre de Physique Théorique, Marseille)
Tuesday 26 November 2013, 10:0011:00
Cambridge University
3720
http://sms.cam.ac.uk/media/1606703
Some statistical properties for random and sequential dynamical systems
Aimino, R (Centre de Physique Théorique, Marseille)
Tuesday 26 November 2013, 10:0011:00
20131129T10:42:37+00:00
3720
1606703
true
16x9
false
no

Speed of convergence to equilibrium for systems with contracting fibers and the logarithm law for Lorenz like flows.
ucs_sms_1580157_1599094
http://sms.cam.ac.uk/media/1599094
Speed of convergence to equilibrium for systems with contracting fibers and the logarithm law for Lorenz like flows.
Galatolo, S (Università di Pisa)
Thursday 14 November 2013, 11:0012:00
Fri, 15 Nov 2013 12:21:03 +0000
Isaac Newton Institute
Galatolo, S
c84ab5c57cb0304f14b700c2b8343a71
2c585527c5807d8bf94c242e0be102bb
c67357fc1837bae3a586df7ec6e7ad6d
802c07b706299e6e379f2013e3b5ac6f
Galatolo, S (Università di Pisa)
Thursday 14 November 2013, 11:0012:00
Galatolo, S (Università di Pisa)
Thursday 14 November 2013, 11:0012:00
Cambridge University
3600
http://sms.cam.ac.uk/media/1599094
Speed of convergence to equilibrium for systems with contracting fibers and the logarithm law for Lorenz like flows.
Galatolo, S (Università di Pisa)
Thursday 14 November 2013, 11:0012:00
A system satisfy a logarithm law if the time which is needed to hit a small target scales as the inverse of the measure of the target. This kind of laws, related to the occurrence of a rare event are also related to the arithmetical properties and to the speed of mixing of the system. I will present a short introduction to the subject and show how a general statement about the speed of convergence to equilibrium for systems with contracting fibers can be applied to deduce the logarithm law for a class of singular hyperbolic flows.
20131115T12:21:03+00:00
3600
1599094
true
16x9
false
no

Statistical stability arguments for maximum kinetic energy dissipation
ucs_sms_1580157_1591256
http://sms.cam.ac.uk/media/1591256
Statistical stability arguments for maximum kinetic energy dissipation
Bertram, J (Australian National University)
Thursday 31 October 2013, 17:0017:35
Mon, 04 Nov 2013 09:58:38 +0000
Isaac Newton Institute
Bertram, J
921649a30e19a27822053096101cf323
1b32b26a9e1d2dcb5af96a2d5d7269b3
c8862268bcf54d02d29fa3a3a94677da
970d91da3e3e402f528d2694d34971e1
Bertram, J (Australian National University)
Thursday 31 October 2013,...
Bertram, J (Australian National University)
Thursday 31 October 2013, 17:0017:35
Cambridge University
1228
http://sms.cam.ac.uk/media/1591256
Statistical stability arguments for maximum kinetic energy dissipation
Bertram, J (Australian National University)
Thursday 31 October 2013, 17:0017:35
The hypothesis that stationary turbulent flows have maximal meanflow kinetic energy dissipation (MaxD) is intriguing because meanflow properties can be predicted without modelling the turbulent component of the flow. Our knowledge of MaxD is largely restricted to relatively simple laboratory flows. Measured Poiseuille flow profiles match MaxD predictions closely and, under these simplified conditions, Malkus's statistical stability argument provides some theoretical justification for MaxD [1]. However, it is not clear whether MaxD is applicable to more complicated fluid systems, like Earth's atmosphere [2]. Recent global climate model simulations have found that the calibrated values of important tunable parameters are indeed consistent with MaxD [3]. Furthermore, the maximum entropy framework [4], which naturally gives a MaxD principle in the case of simple laboratory flows, can be readily applied to more complicated systems. I will discuss attempts to gener alise the Malkus statistical stability argument and how this connects with maximum entropy arguments. In doing so I hope to compare the physical insights of statistical stability, which emphasises dynamical resilience to perturbations, with maximum entropy considerations, which ignore system dynamics.
[1] W. V. R. Malkus. Borders of disorder: In turbulent channel ow. Journal of Fluid Mechanics, 489:185{198, 2003. [2] Richard Goody. Maximum entropy production in climate theory. Journal of the atmospheric sciences, 64(7):27352739, 2007. [3] Salvatore Pascale, Jonathan M. Gregory, Maarten H.P. Ambaum, and Remi Tailleux. A parametric sensitivity study of entropy production and kinetic energy dissipation using the FAMOUS AOGCM. Climate Dynamics, 38(56):12111227, 2012. [4] Dewar R and Maritan A. A theoretical basis for maximum entropy production. 2013. In Beyond the Second Law: Entropy Production and Nonequilibrium Systems (eds. R Dewar, C Lineweaver, R Niven, K RegenauerLieb), Springer, In Press
20131104T10:01:05+00:00
1228
1591256
true
16x9
false
no

Statistics of eddy transport
ucs_sms_1580157_1591263
http://sms.cam.ac.uk/media/1591263
Statistics of eddy transport
Vlad, M (National Institute of Laser, Plasma and Radiation Physics)
Thursday 31 October 2013, 17:3518:10
Mon, 04 Nov 2013 11:26:06 +0000
Isaac Newton Institute
Vlad, M
9aba64d92a8fc2e0fc1e6490167ed63b
24d1fc4a5c225e50109bfaccca48c793
35214da8e49edd943aedd4b956125722
38cc87863d1b61384e07c3638d20b8aa
Vlad, M (National Institute of Laser, Plasma and Radiation Physics)
Thursday...
Vlad, M (National Institute of Laser, Plasma and Radiation Physics)
Thursday 31 October 2013, 17:3518:10
Cambridge University
1978
http://sms.cam.ac.uk/media/1591263
Statistics of eddy transport
Vlad, M (National Institute of Laser, Plasma and Radiation Physics)
Thursday 31 October 2013, 17:3518:10
Coauthor: Florin Spineanu (National Institute of Laser, Plasma and Radiation Physics)
A semianalytical method for the study of eddy transport in presented. It determines the statistics of particle trajectories using the decorrelation trajectories, which are determined from the Eulerian correlation of the velocity. The fraction of free trajectories that effectivy determines the transport decreases with the increase of the Kubo number. The statistical method is able to describe the transport in these conditions where it is produced by a minority of the events. The effect of particle collisions is analysed. We show that eddy diffusion is strongly amplified by weak collisions and that the effective diffusion coefficient can be much larger than both the collisional diffusion coefficient and the eddy diffusion coefficients.
20131104T11:26:32+00:00
1978
1591263
true
16x9
false
no

Stochastic modeling and predictability: Analysis of a loworder coupled ocean atmosphere model
ucs_sms_1580157_1594758
http://sms.cam.ac.uk/media/1594758
Stochastic modeling and predictability: Analysis of a loworder coupled ocean atmosphere model
Vannitsem, S (Royal Meteorological Institute of Belgium)
Thursday 07 November 2013, 11:0012:00
Fri, 08 Nov 2013 12:23:56 +0000
Isaac Newton Institute
Vannitsem, S
8c64271759d9b0b9edf7909d7283ae69
fa9c28da63b22e33f184cb9983b44e74
13bedca3fda56df15f53f17a15b18edc
494b5ea9e346bc5f52a13b340628f60c
Vannitsem, S (Royal Meteorological Institute of Belgium)
Thursday 07 November...
Vannitsem, S (Royal Meteorological Institute of Belgium)
Thursday 07 November 2013, 11:0012:00
Cambridge University
2689
http://sms.cam.ac.uk/media/1594758
Stochastic modeling and predictability: Analysis of a loworder coupled ocean atmosphere model
Vannitsem, S (Royal Meteorological Institute of Belgium)
Thursday 07 November 2013, 11:0012:00
20131108T12:23:56+00:00
2689
1594758
true
16x9
false
no

The influence of fast waves and fluctuations on the evolution of three slow solutions of the Boussinesq equations
ucs_sms_1580157_1612291
http://sms.cam.ac.uk/media/1612291
The influence of fast waves and fluctuations on the evolution of three slow solutions of the Boussinesq equations
Wingate, B (University of Exeter)
Wednesday 04 December 2013, 14:4515:30
Mon, 09 Dec 2013 12:22:20 +0000
Isaac Newton Institute
Wingate, B
928fb1664bb233f2e20c30fb78fe57b4
bd0be1b63f7a1d887849b6f6f8d688e0
4948f1435d0fbfcdec2ae3cbd961c7be
384a34db649e4354eb579d7e1cf35571
Wingate, B (University of Exeter)
Wednesday 04 December 2013, 14:4515:30
Wingate, B (University of Exeter)
Wednesday 04 December 2013, 14:4515:30
Cambridge University
3024
http://sms.cam.ac.uk/media/1612291
The influence of fast waves and fluctuations on the evolution of three slow solutions of the Boussinesq equations
Wingate, B (University of Exeter)
Wednesday 04 December 2013, 14:4515:30
Coauthors: Jared P. Whitehead (Brigham Young University), Terry Haut (Los Alamos National Laboratory)
We present results from a study of the impact of the nonslow (typically fast) components of a rotating, stratified flow on its slow dynamics. We examine three known slow limits of the rotating and stratified Boussinesq equations: strongly stratified flow (Fr→0,Ro≈O(1) ), strongly rotating flow (Ro→0,Fr≈O(1) ) and QuasiGeostrophy (Ro→0,Fr→0,Fr/Ro=f/N finite).
In order to understand how the flow approaches and interacts with the slow dynamics we decompose the full solution into a component that is projected onto the null space of the fast operator and everything else. We use this decomposition to find evolution equations for the flow (and corresponding energy) on and off the slow manifold.
Numerical simulations indicate that for the geometry considered (triply periodic) and the type of forcing applied, the fast waves act as a conduit, moving energy onto the slow manifold. This decomposition clarifies how the energy is exchanged when either the stratification or the rotation is weak. In the quasigeostrophic limit the energetics are less clear, however it is observed that the energy off the slow manifold equilibrates to a quasisteady value.
At the end I will discuss how greater understanding of flow/fast dynamics could impact emerging numerical algorithms designed for future computer architectures.
20131209T12:22:20+00:00
3024
1612291
true
16x9
false
no

The modeling of rare events: from methodology to practice and back
ucs_sms_1580157_1591221
http://sms.cam.ac.uk/media/1591221
The modeling of rare events: from methodology to practice and back
Embrechts, P (ETH Zürich)
Thursday 31 October 2013, 13:4014:15
Mon, 04 Nov 2013 10:15:41 +0000
Isaac Newton Institute
Embrechts, P
6a981ea8f36d3475c5ce83d409fa32a6
b420eae08639d37a6af631414ddc2dab
e4a013a6b61ad9dcf10251148494c68b
74e11a4b9cf287df77825758f0ebae36
Embrechts, P (ETH Zürich)
Thursday 31 October 2013, 13:4014:15
Embrechts, P (ETH Zürich)
Thursday 31 October 2013, 13:4014:15
Cambridge University
2259
http://sms.cam.ac.uk/media/1591221
The modeling of rare events: from methodology to practice and back
Embrechts, P (ETH Zürich)
Thursday 31 October 2013, 13:4014:15
In this talk I give a brief overview of the historical development of Extreme Value Theory (EVT), discuss some applications, highlighting EVT's strengths and weaknesses, and indicate relevant research themes going forward.
20131104T10:16:28+00:00
2259
1591221
true
16x9
false
no

The modified second fluctuationdissipation theorem
ucs_sms_1580157_1589175
http://sms.cam.ac.uk/media/1589175
The modified second fluctuationdissipation theorem
Maes, C (Katholieke Universiteit Leuven)
Wednesday 30 October 2013, 13:4014:15
Thu, 31 Oct 2013 13:05:27 +0000
Isaac Newton Institute
Maes, C
8eb115d05d024c5e15ee97bd3d985fe9
bc90c4c65e8ad53cb40b5408754874f7
1dcd974da8c5d012971b971dfdbdc500
d0a956fd79fe2c84dc0c95cebd01de07
Maes, C (Katholieke Universiteit Leuven)
Wednesday 30 October 2013, 13:4014:15
Maes, C (Katholieke Universiteit Leuven)
Wednesday 30 October 2013, 13:4014:15
Cambridge University
2528
http://sms.cam.ac.uk/media/1589175
The modified second fluctuationdissipation theorem
Maes, C (Katholieke Universiteit Leuven)
Wednesday 30 October 2013, 13:4014:15
Baths produce friction and random forcing on particles suspended in them. The relation between noise and friction in (generalized) Langevin equations is usually referred to as the second fluctuationdissipation theorem. We show, beyond formalities, what is the proper nonequilibrium extension, to be applied when the environment is itself active and driven.
20131031T13:05:58+00:00
2528
1589175
true
16x9
false
no

The nonlinear local Lyapunov exponent (NLLE) and its application to predictability study
ucs_sms_1580157_1602076
http://sms.cam.ac.uk/media/1602076
The nonlinear local Lyapunov exponent (NLLE) and its application to predictability study
Li, J (Institute of Atmospheric Physics, Chinese Academy of Sciences)
Tuesday 19 November 2013, 11:0012:00
Wed, 20 Nov 2013 15:59:02 +0000
Isaac Newton Institute
Li, J
d7054f69b305dccbbc8d5ee53a538f50
b70de8d7b1bc09e6f3d8bc4ab1aecf3f
ed6e51394924b780f9d54bc4ec9d3c35
f36fcee65ffd3e450aeeb7c805f88813
Li, J (Institute of Atmospheric Physics, Chinese Academy of Sciences)
Tuesday...
Li, J (Institute of Atmospheric Physics, Chinese Academy of Sciences)
Tuesday 19 November 2013, 11:0012:00
Cambridge University
3283
http://sms.cam.ac.uk/media/1602076
The nonlinear local Lyapunov exponent (NLLE) and its application to predictability study
Li, J (Institute of Atmospheric Physics, Chinese Academy of Sciences)
Tuesday 19 November 2013, 11:0012:00
20131120T15:59:02+00:00
3283
1602076
true
16x9
false
no

The Range of Planetary Circulations Described by the Dry Primitive Equations
ucs_sms_1580157_1614562
http://sms.cam.ac.uk/media/1614562
The Range of Planetary Circulations Described by the Dry Primitive Equations
Vallis, G (University of Exeter)
Friday 06 December 2013, 09:0009:45
Wed, 11 Dec 2013 17:43:05 +0000
Isaac Newton Institute
Vallis, G
1e4dae2975266ddf6d176e4a822b9ddd
e73e10aecb203c4ba8561c964c4de3fe
7d8eaa436daa9844e9ad2a3ea23d6aa7
d62413b5951d14ccf8b8177545841477
Vallis, G (University of Exeter)
Friday 06 December 2013, 09:0009:45
Vallis, G (University of Exeter)
Friday 06 December 2013, 09:0009:45
Cambridge University
2857
http://sms.cam.ac.uk/media/1614562
The Range of Planetary Circulations Described by the Dry Primitive Equations
Vallis, G (University of Exeter)
Friday 06 December 2013, 09:0009:45
Coauthors: Jonathan Mitchell (UCLA), Sam Potter (Princeton University)
The dry primitive equations can, with appropriate forcing and dissipation, provide a reasonable simulation of the largescale features of the Earth's atmosphere and ocean. In this talk I will describe the behaviour of these PDEs when they are taken out of the terrestrial parameter regime. In n particular, I will describe their behaviour when the thermal Rossby number, Ekman number and a radiative relaxation timescale are varied considerably, moving into a parameter regime more appropriate for Mars or Titan.
I will pay particular attention to the formation of zonal jets, and in particular of equatorial superrotation, which is a feature of some other planets. It is wellknown that zonal jets robustly arise in rotating atmospheres if there is a wavemaker at a particular latitude. Rossby waves are then generated that propagate away, and eastward momentum converges on the source region producing a zonal jet. The Earth's jet stream is, in part, formed this way. However, on slowly rotating atmospheres it seems unlikely that superrotation is produced by that mechanism. Rather, simulations indicate that, at small thermal Rossby number, a mechanism involving equatorial Kelvin waves is involved.
20131211T17:43:05+00:00
2857
1614562
true
16x9
false
no

The semigeostrophic system for largescale atmospheric flows
ucs_sms_1580157_1613265
http://sms.cam.ac.uk/media/1613265
The semigeostrophic system for largescale atmospheric flows
Pelloni, B (University of Reading)
Thursday 05 December 2013, 16:0016:45
Tue, 10 Dec 2013 09:50:28 +0000
Isaac Newton Institute
Pelloni, B
e6464135572f3a024afe5879e0d43046
3f3faeacba57c1621b00bf9f405bd0fc
dc8ca73a7938f1d9fde44df55235185f
b71d4f7b8a78de7d1a95842aa0c9e4ff
Pelloni, B (University of Reading)
Thursday 05 December 2013, 16:0016:45
Pelloni, B (University of Reading)
Thursday 05 December 2013, 16:0016:45
Cambridge University
2603
http://sms.cam.ac.uk/media/1613265
The semigeostrophic system for largescale atmospheric flows
Pelloni, B (University of Reading)
Thursday 05 December 2013, 16:0016:45
Coauthor: Mike Cullen (Met Office)
I could present results on the existence of solutions in 3D, free boundary setting as well as some preliminary results on the validity of the model as a reduction of the Euler system.
20131210T09:50:28+00:00
2603
1613265
true
16x9
false
no

The thermostated dynamical systems approach to nonequilibrium steady states
ucs_sms_1580157_1594751
http://sms.cam.ac.uk/media/1594751
The thermostated dynamical systems approach to nonequilibrium steady states
Klages, R (Queen Mary University of London)
Thursday 07 November 2013, 10:0011:00
Fri, 08 Nov 2013 12:45:00 +0000
Isaac Newton Institute
Klages, R
1a74dd289452f7ccc91c60001d956590
bd71d4e4d48add2e9eafe34d594b5496
eecab50205213c8968389b8615c25258
2cf4b47af5724fe519810b50870626f0
Klages, R (Queen Mary University of London)
Thursday 07 November 2013,...
Klages, R (Queen Mary University of London)
Thursday 07 November 2013, 10:0011:00
Cambridge University
3720
http://sms.cam.ac.uk/media/1594751
The thermostated dynamical systems approach to nonequilibrium steady states
Klages, R (Queen Mary University of London)
Thursday 07 November 2013, 10:0011:00
In this talk I will outline a theory that aims at understanding the emergence of irreversible macroscopic transport starting from reversible microscopic dynamics. At the heart of this approach is to suitably model the interaction of a subsystem with a thermal reservoir. A simple example is a tracer particle in a fluid exhibiting Brownian motion for which there is the wellknown description in terms of stochastic Langevin dynamics. Three decades ago scientists proposed a fully deterministic, time reversible modeling of thermalized motion by deriving a generalized Hamiltonian formalism yielding generalized friction coefficients in terms what is called Gaussian and Nos´eHoover thermostats. Surprisingly, in nonequilibrium situations such as, e.g., under an external electric field, this time reversible dissipative dynamics generates fractal attractors, exhibits an identity between phase space contraction and entropy production, and furnishes formulas that express transport coefficients in terms of Lyapunov exponents. In my talk I will show how this class of dynamical systems is constructed, will review its basic dynamical systems properties, and will critically discuss a conjectured universality of these properties. I will present a rather general summary of this approach, not much preknowledge about this particular field of research is required. [1] R.Klages, Microscopic Chaos, Fractals and Transport in Nonequilibrium Statistical Mechanics (World Scientific, Singapore, 2007)
20131108T12:45:00+00:00
3720
1594751
true
16x9
false
no

The weather: emergent laws and multi fractal cascades
ucs_sms_1580157_1585108
http://sms.cam.ac.uk/media/1585108
The weather: emergent laws and multi fractal cascades
Lovejoy, S (McGill University)
Wednesday 23 October 2013, 11:0012:00
Fri, 25 Oct 2013 10:16:27 +0100
Isaac Newton Institute
Lovejoy, S
f6f31a75eca85e4ae53a1f11828338aa
e736ae53fbd2571a38fe548660e69c9d
2cdd401307350d9c41d95ce8583f6ba6
8073f15f9bf4962e28e096d34ea0052b
Lovejoy, S (McGill University)
Wednesday 23 October 2013, 11:0012:00
Lovejoy, S (McGill University)
Wednesday 23 October 2013, 11:0012:00
Cambridge University
4620
http://sms.cam.ac.uk/media/1585108
The weather: emergent laws and multi fractal cascades
Lovejoy, S (McGill University)
Wednesday 23 October 2013, 11:0012:00
20131025T10:17:05+01:00
4620
1585108
true
16x9
false
no

Thermodynamic properties of the climate system
ucs_sms_1580157_1585115
http://sms.cam.ac.uk/media/1585115
Thermodynamic properties of the climate system
Lucarini, V (University of Reading)
Wednesday 23 October 2013, 15:0016:00
Fri, 25 Oct 2013 10:26:33 +0100
Isaac Newton Institute
Lucarini, V
2609f7f6b1be1da284fb5f65468577dc
05e84b49494e1bfbe2923769370a993f
bac4df2e2152a96db8bc2f3ad32788d1
128c3246d114a957bffe957c0a06a78e
Lucarini, V (University of Reading)
Wednesday 23 October 2013, 15:0016:00
Lucarini, V (University of Reading)
Wednesday 23 October 2013, 15:0016:00
Cambridge University
4980
http://sms.cam.ac.uk/media/1585115
Thermodynamic properties of the climate system
Lucarini, V (University of Reading)
Wednesday 23 October 2013, 15:0016:00
20131025T10:27:04+01:00
4980
1585115
true
16x9
false
no

Thermostats for bias correction and statistically consistent model reduction
ucs_sms_1580157_1593511
http://sms.cam.ac.uk/media/1593511
Thermostats for bias correction and statistically consistent model reduction
Frank, J (Utrecht University)
Tuesday 05 November 2013, 10:0011:00
Wed, 06 Nov 2013 09:25:18 +0000
Isaac Newton Institute
Frank, J
a7b8d1d74803389c7c74bfd1b06422c8
6d5d75507aadea5f58cbd059b8c1b331
0023ffe04698cd30dbd04f9407d8421b
258c7e680d5a5561c396d6add6c0e204
Frank, J (Utrecht University)
Tuesday 05 November 2013, 10:0011:00
Frank, J (Utrecht University)
Tuesday 05 November 2013, 10:0011:00
Cambridge University
3449
http://sms.cam.ac.uk/media/1593511
Thermostats for bias correction and statistically consistent model reduction
Frank, J (Utrecht University)
Tuesday 05 November 2013, 10:0011:00
In meteorology and climate science, fluid models are simulated on time scales very long compared to the characteristic Lyapunov time of chaotic growth, with the goal of generating a data set suitable for statistical analysis. The choice of a numerical discretization scheme for a problem carries with it a certain bias in the statistical data generated in long simulations. In this talk I will discuss research on the use of thermostat techniques, commonly used in molecular dynamics, to control the invariant measure of a discretized model, with the goals of correcting bias or effecting a statistically consistent model reduction. These will be illustrated for a pointvortex gas and a Burgers/KdV equation. Finally I will discuss new extensions of the approach to cases where observations are available.
20131106T09:25:19+00:00
3449
1593511
true
16x9
false
no

Trapping of Rossby waves in the equatorial betaplane model
ucs_sms_1580157_1609031
http://sms.cam.ac.uk/media/1609031
Trapping of Rossby waves in the equatorial betaplane model
Gallagher, I (Université Paris 7  DenisDiderot)
Monday 02 December 2013, 09:1510:15
Tue, 03 Dec 2013 14:16:25 +0000
Isaac Newton Institute
Gallagher, I
d49de8e3aee698d3a487261f521e1de9
4d2ef89f539d009b79e389c443a77e8a
e9caf13f2f1a250c5d7559c7213faba3
bb98fa015c2dc2db083c1e602762e459
Gallagher, I (Université Paris 7  DenisDiderot)
Monday 02 December 2013,...
Gallagher, I (Université Paris 7  DenisDiderot)
Monday 02 December 2013, 09:1510:15
Cambridge University
3660
http://sms.cam.ac.uk/media/1609031
Trapping of Rossby waves in the equatorial betaplane model
Gallagher, I (Université Paris 7  DenisDiderot)
Monday 02 December 2013, 09:1510:15
In this talk we shall report on joint works with Christophe Cheverry, Thierry Paul and Laure SaintRaymond in which we study an equatorial shallow water system under the betaplane approximation. We prove that in some asymptotic regimes, Rossby waves are trapped around the equator while Poincaré waves disperse. This involves the use of microlocal techniques related to semiclassical analysis, such as Mourre estimates, and some ODE methods.
20131203T14:16:25+00:00
3660
1609031
true
16x9
false
no

Turbulence transition in shear flows: coherent structures, edge states and all that
ucs_sms_1580157_1591725
http://sms.cam.ac.uk/media/1591725
Turbulence transition in shear flows: coherent structures, edge states and all that
Eckhardt, B (PhilippsUniversität Marburg )
Friday 01 November 2013, 11:1011:45
Mon, 04 Nov 2013 11:53:26 +0000
Isaac Newton Institute
Eckhardt, B
575c3479b42311939bfc8c0bd4c1f40d
a849f25a9e17dd44cd2860e84f0a3f46
e12cb64e04f6e54e3679d350f634918d
7dcb6e822adc67afb0b8452d4c18a1a5
Eckhardt, B (PhilippsUniversität Marburg )
Friday 01 November 2013,...
Eckhardt, B (PhilippsUniversität Marburg )
Friday 01 November 2013, 11:1011:45
Cambridge University
2195
http://sms.cam.ac.uk/media/1591725
Turbulence transition in shear flows: coherent structures, edge states and all that
Eckhardt, B (PhilippsUniversität Marburg )
Friday 01 November 2013, 11:1011:45
Pipe flow, plane Couette flow and several other shear flows show a transition to turbulence for flow rates where the linear profile is still stable. The turbulent dynamics is transient, so that the transition is related to the formation of a chaotic saddle in the state space of the system. The saddle is supported by exact coherent states and their heteroclinic connections. I will summarize the common features that appear across all these shear flows, sketch the numerical techniques used to identify and track the relevant structures in the state space of the system and point out possible applications beyond fluid mechanics.
20131104T11:54:07+00:00
2195
1591725
true
16x9
false
no

Typical behaviour of extremes of chaotic dynamical systems for general observables
ucs_sms_1580157_1588434
http://sms.cam.ac.uk/media/1588434
Typical behaviour of extremes of chaotic dynamical systems for general observables
Kuna, T (University of Reading)
Tuesday 29 October 2013, 11:1011:45
Wed, 30 Oct 2013 12:19:59 +0000
Isaac Newton Institute
Kuna, T
797af3b30972888430ce0a664146a775
719c58e50744c6ce619a47fade875784
58eb1df53873ed35bddf6081f207b95c
987077a7d1c7de705bd46aed6838482d
Kuna, T (University of Reading)
Tuesday 29 October 2013, 11:1011:45
Kuna, T (University of Reading)
Tuesday 29 October 2013, 11:1011:45
Cambridge University
2003
http://sms.cam.ac.uk/media/1588434
Typical behaviour of extremes of chaotic dynamical systems for general observables
Kuna, T (University of Reading)
Tuesday 29 October 2013, 11:1011:45
In this talk we discuss the distribution of extreme events for a chaotic dynamical system for a general class of observables. More precisely, we link directly the distribution of events over threshold to the local geometrical structure on the surface of the attractor. It is shown how this can provide us with information about the local stable and unstable dimensions. Using Ruelle's response theory, we discuss the sensitivity of the parameters of the distribution under perturbations. This is a joint work with Vlaerio Lucarini, Davide Faranda and Jeroen Wouters.
20131030T12:20:32+00:00
2003
1588434
true
16x9
false
no

Use of the semigeostrophic model in understanding largescale atmosphere and ocean flows
ucs_sms_1580157_1612403
http://sms.cam.ac.uk/media/1612403
Use of the semigeostrophic model in understanding largescale atmosphere and ocean flows
Cullen, M (Met Office)
Thursday 05 December 2013, 09:1510:15
Mon, 09 Dec 2013 13:02:29 +0000
Isaac Newton Institute
Cullen, M
045fdf8f8c2ab5be435265616679a8b8
b8ddc086e98b40dd52e503285af3c4d4
51e96439dcd196a52035720d39c90c33
0af3a4b03802dc168e1fe248b471ec38
Cullen, M (Met Office)
Thursday 05 December 2013, 09:1510:15
Cullen, M (Met Office)
Thursday 05 December 2013, 09:1510:15
Cambridge University
3780
http://sms.cam.ac.uk/media/1612403
Use of the semigeostrophic model in understanding largescale atmosphere and ocean flows
Cullen, M (Met Office)
Thursday 05 December 2013, 09:1510:15
The semigeostrophic model is an accurate approximation to the NavierStokes equations when the Lagrangian Rossby number is small and the aspect ratio is less than f/N (where f is the Coriolis parameter and N the BruntVaisala frequency). In practice this leads to a horizontal scale of around 1000km in the atmosphere and 100km in the ocean. The approximation is second order accurate in the limit epsilon tends to zero where the Rossby number is O(epsilon) and the Froude number O(sqrt(epsilon)). This approximation has a big advantage over the quasigeostrophic approximation because it allow O(1) variations of the static stability, Coriolis parameter and orographic height. These features are essential in describing largescale flows. The stability of the solutions of this system is consistent with the observed persistence of largescale anomalies in the atmosphere and ocean. The failure of the approximation on smaller scales is associated with the lack of such structures on smal ler scales in the observed system. The talk will demonstrate how the semigeostrophic model can be used to validate numerical methods, and how it can be extended to include a realistic model of the atmospheric boundary layer.
20131209T13:02:29+00:00
3780
1612403
true
16x9
false
no
1580157