The subject of the seminar this year is Data assimilation for atmosphere and ocean, and was held at ECMWF from 6 to 9 September 2011.
Description
Data assimilation is at the core of ECMWF numerical weather prediction activities. Increasing the accuracy of the forecast relies on the provision of increasingly accurate initial states for the prediction system. Variational data assimilation has been successfully developed and used operationally at ECMWF, today the variational system is a pre-requisite for the assimilation of satellite data and effective use of conventional observations in the atmosphere. Ocean data assimilation is also an integral part of the monthly and seasonal forecast systems. An extension of variational techniques including longer assimilation windows and weak constraint methods to allow for inclusion of model error estimates are current research areas. Ensemble based assimilation systems are currently under development and combined with the variational technique to allow for a flow dependent estimation of background error variances and covariances. The Ensemble Kalman Filter method has been applied to operational NWP and Extended Kalman Filter methods have been developed for surface parameter assimilation. The development of ensemble based assimilation techniques implies that initial state perturbation methods and the representation of model error are essential elements of data assimilation systems thus providing close links with ensemble prediction methods.
The seminar will give a pedagogical review of the principles behind data assimilation techniques and provide detailed descriptions of the currently used assimilation techniques. An overview of the observation data sources and their intrinsic properties will be given. Outlooks on future developments in data assimilation such as ensemble based methods and weak constraint variational methods will also be included. Last but not least, challenges related to the design of efficient data assimilation schemes on future computer architectures will be addressed.
Programme
Presentations
| Tuesday 6 September | |
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Welcome Erland Källén (ECMWF) |
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Developments in variational data assimilation Andrew Lorenc (UK Met-Office) |
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Developments in ensemble data assimilation Jeff Whitaker (NOAA) |
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Hybrid variational/ensemble data assimilation Dale Barker (UK Met-Office) |
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Pre- and post-processing in data assimilation Florence Rabier (Météo-France) |
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Stratospheric and mesospheric data assimilation Saroja Polavarapu (Environment Canada) |
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Convective scale data assimilation and nowcasting Sue Ballard (Met-Office, Reading) |
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| Wednesday 7 September | |
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The Global Observing System in the data assimilation context Michele Rienecker (GMAO) |
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Current status and future of satellite data assimilation John Derber (NCEP) |
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Observation error specifications Gerald Desroziers (Météo-France) |
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Monitoring the assimilation and forecast system performance Carla Cardinali (ECMWF) |
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Data assimilation of the hydrological cycle Jean-Francois Mahfouf (Météo-France) |
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Land surface data assimilation Patricia de Rosnay (ECMWF) |
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| Thursday 8 September | |
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Ensemble of data assimilations and uncertainty estimation Massimo Bonavita (ECMWF) |
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Non-linear data assimilation Chris Snyder (UCAR, Colorado) |
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Nonlinear large-dimensional data assimilation: the potential of particle filters Peter Jan v Leeuwen (University of Reading) |
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Long window weak-constraint 4D-Var Mike Fisher (ECMWF) |
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Recent developments in ocean data assimilation Andy Moore (University of California) |
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Reanalysis Paul Poli (ECMWF) |
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| Friday 9 September | |
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Coupled Data Assimilation – ocean, mixed layer, land and atmosphere interaction Keith Haines (ESSC) |
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Coupled data assimilation for atmospheric constituents Adrian Simmons (ECMWF) |
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Data Assimilation on future computer architectures Lars Isaksen (ECMWF) |
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Proceedings
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Convective scale data assimilation S.P. Ballard |
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Hybrid variational-ensemble data assimilation D.M. Barker |
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Ensemble of data assimilations and uncertainty estimation M. Bonavita |
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GPS-RO at ECMWF C. Cardinali |
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Land surface data assimilation P. de Rosnay |
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Current status and future of satellite data assimilation J.C. Derber |
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Observation error specifications G. Desroziers |
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Long window 4D-Var M. Fisher |
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Coupled atmospheric-ocean data assimilation K. Haines |
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Data assimilation on future computer architectures L. Isaksen |
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Developments of variational data assimilation A.C. Lorenc |
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Data assimilation of the hydrological cycle J-F. Mahfouf |
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Some challenges and advances in regional ocean data assimilation A.M. Moore |
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Stratospheric and mesospheric reanalysis S. Polavarapu |
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Data assimilation for atmospheric reanalysis P. Poli |
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Pre- and post- processing in data assimilation F. Rabier |
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The global observing system in the data assimilation context M.R. Rienecker |
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Particle filters, the optimal proposal and high-dimensional systems C. Snyder |
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Nonlinear large-scale data assimilation: The potential of particle filters P.J. Van Leeuwen |
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Developments in ensemble data assimilation J.S. Whitaker |
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