Week 2 - Monday 21st to Thursday 25th September 1998

Workshop on Atmospheres and Oceans

PROGRAMME

Monday 21 September - DATA ASSIMILATION AND VORTEX DYNAMICS How are observations best put to use in numerical models of the atmosphere and oceans? In particular, can they help improve the models themselves, either through suggesting a better formulation of the equations or by tuning parameters in parameterisations? Can we think of flexible assimilation methods that e.g. work for numerical methods having lagrangian (i e contour advection) aspects? Is there an optimal way of projecting data onto numerical fields? 8:55 - 9:00: OPENING REMARKS 9:00 - 10:00: R.H.J. Grimshaw (Monash), "Models for coherent structures in the atmosphere and ocean" 10:00 - 11:00: R. Pasmanter (KNMI), "The statistics of the atmosphere fluctuations, and the Fisher metric." ** coffee ** 11:30 - 12:30: X. Carton, R. Baraille, S. Hoang, N. Filatoff (SHOM, Brest) "Adaptive filtering - theory and application to satellite altimetry data assimilation into a primitive-equations model" ** lunch, free time ** 15:00 - 16:00: R. Buizza (ECMWF), "Targeting observations using singular vectors" ** tea ** 16:30 - 17:30: N.J. Zabusky (Rutgers), "Vortex dynamics of accelerated inhomogeneous flows: visiometrics and modelling" 17:30 - 18:10: J.J. Rasmussen (Risoe), "Experimental and numerical investigations of shear flow instabilities in rotating shallow water"

Tuesday 22 September - NUMERICAL ISSUES IN GEOPHYSICAL MODELLING How do we best re-write the governing equations to get accurate solutions efficiently? How do we best formulate the numerical methods? How should we approach modelling flows in different asymptotic regimes (e g of Burger number)? What collection of fundamental test problems should we be using to benchmark new methods, as well as old ones? How do we best perform inter- and intra-model comparisons? What is the appropriate use of idealised or simplified models? 9:00 - 10:00: M.J.P. Cullen (UK Met. Office), "The behaviour of atmospheric flow in different asymptotic regimes, and implications for numerical methods" 10:00 - 11:00: M.H.P. Ambaum (KNMI & Reading), "How to include non-conservative effects in a Lagrangian model of atmospheric flow" ** coffee ** 11:30 - 12:30: T. Davies (UK Met. Office), "Atmospheric test problems for validating numerical schemes" ** lunch, free time ** 15:00 - 15:40: D.G. Dritschel (Warwick), "Markedly improved algorithms for modelling gravity wave propagation: putting classical theory to good use!" 15:40 - 16:20: J. Thuburn (Reading), "Characteristic treatment of gravity waves - a cure for orographic resonance?" ** tea ** 16:50 - 17:30: S. Yoden (Kyoto), "Numerical experiments on 2-D turbulence on a rotating sphere with high resolution models" 17:30 - 18:10: E.C. Neven (Utrecht), "Families of direct inversion balanced models: the subtle interplay between numerics and theory"

Wednesday 23rd September - MODELLING REQUIREMENTS FOR IMPROVED PREDICTABILITY What limits the accuracy of atmospheric and ocean models in making short-term and long-term predictions? Are we content with the measures of accuracy presently used to judge the quality of a prediction, or should we consider others and why? What are we learning from ensemble forecasting? What are the roles played by statistical and deterministic prediction? What new approaches have recently been developed or could be developed to bring about improved predictability (e g dynamic grid refinement, focusing on (normally rare?) energetic events (e g deep convection) in local regions of space-time, contour advection for dealing with quasi- conservative, fine-scale fields, etc)? 9:00 - 10:00: D.G. Dritschel (Warwick), "Why we should avoid grid-based advection, and how we can do it in realistic numerical models of the atmospheric and oceanic circulation" 10:00 - 11:00: J.J. Rasmussen (Risoe), "Transport and mixing in two-dimensional turbulent flows dominated by vortex structures" 11:30 - 12:30: J.D. Gibbon (Imperial), “Dynamically stretched columnar vortex solutions of the Navier-Stokes and Euler equations” 14.20 - 15.00 J. Stirling (Loughborough), "Nonlinear dynamics, patchiness and pollution in an Estuarine flow" 15:00 - 15:40: O. Buhler (Cambridge), "The 'pseudomomentum rule' for modelling wave-mean interactions" 16:10 - 16:50: R. Buizza (ECMWF), "The ECMWF Ensemble Prediction System" 16:50 - 17:30: S. Yoden (Kyoto), "Low-frequency variations and predictability fluctuations in a barotropic model with zonal asymmetry" 17:30 - 18:10: A. Mahalov & B. Nicolaenko (Arizona), "Issues of resolving anisotropic turbulence in atmospheric flows"

Thursday 24th September - NUMERICAL MODELLING OF THE OCEANS What are the major modelling issues in predicting the ocean circulation down to scales below the Rossby radius of deformation? What are the primary considerations?: coastlines, topography, accurate wind forcing, accurate modelling of potential vorticity, thermohaline circulations, convection, shear-instability and vertical mixing, ice? Where do we stand on forecasting the ocean mesoscale, shelf seas, and climate - can we design one model to do all three? What numerical methods can be developed that are flexible enough to deal with the vast range of spatial and temporal scales present in the ocean without crippling the world's computational resources? 9:00 - 10:00: M. Bell (UK Met. Office), "Requirements and opportunities for a new numerical ocean model" 10:00 - 11:00: P. Rhines (Washington), "Potential vorticity and geophysical circulations" ** coffee ** 11:30 - 12:30: G. Vallis (UCSD), "Useful and useless balanced models for large- and meso-scale modelling" ** lunch, free time ** 15:00 - 15:40: E.R. Johnson (UCL), "Modelling nonlinear coastal flows" 15:40 - 16:20: X. Carton (SHOM, Brest), "Geostrophic vortex stability" ** tea ** 16:50 - 17:30: R.H.J. Grimshaw (Monash), "Weakly nonlinear model for instability generated by mode resonance: wave growth and possible collapse" 17:30 - 18:00: E.S. Benilov (Warwick), "On the stability of zonal jets in a rough-bottomed ocean on the barotropic beta-plane" 18:00 - 18:30: G. Reznik (Moscow), "Baroclinic instability of large-scale ocean currents as a source of intense open ocean mesoscale motion"

Friday 25th September - DEALING WITH UNRESOLVED SCALES IN ATMOSPHERIC/OCEANIC MODELS What is actually done in sub-grid models? What is the consistent way of coupling such models to larger-scale, resolved dynamics? Do the truncated equations being simulated generate their own artificial sub-grid dynamics, and how do we compensate for this? (Can we, without causing the model to blow up? - the collective effects of unresolved scales may not act like diffusion and may therefore be problematic for numerical stability.) What are the latest ideas for parameterising sub-grid scale processes, particularly in the context of the chemical reactions responsible for ozone depletion, tracer transport in the atmosphere and the oceans, turbulence, and unresolved orography? 9:00 - 10:00: R. Buizza (ECMWF), "Stochastic simulation of model uncertainties in the ECMWF Ensemble Prediction System" 10:00 - 11:00: P. Mason (UK Met. Office), "Subgrid models and filter operations" ** coffee ** 11:30 - 12:30: P. Rhines (Washington), "Deep convection and climate change: observations, laboratory- and numerical models" ** lunch, free time ** 15:00 - 15:40: R. Kershaw (UK Met. Office), "The functions of parametrised convection in numerical weather prediction and climate models" 15:40 - 16:20: S.H. Derbyshire (UK Met. Office), "Computational and parametrisation aspects of stable boundary layers ... and other vexing problems" ** tea ** 16:50 - 17:30: S. Nazarenko (Warwick), "Dynamical modelling of subgrid scales based on the non-locality property"

Week 1 - detailed programme
WARWICK WEEKEND - detailed programme

Mrs. Peta McAllister, Mathematics Research Centre, University of Warwick, Coventry CV4 7AL - UK
Phone: 44 + (0)1203 - 524403
Fax: 44 + (0)1203 - 523548
E-mail: peta@maths.warwick.ac.uk