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RISImpact of the Digital Filter as a Weak Constraint in the Preoperational 4DVAR Assimilation System of Météo-France
Publisher: American Meteorological Society
Abstract: In this paper, a weak constraint formulation of the digital filter based on the Dolph?Chebyshev window is introduced in a preoperational version of the 4DVAR analysis of Météo-France. The constraint is imposed only on the ...
Impact of MODIS Polar Winds in ECMWF's 4DVAR Data Assimilation System
Publisher: American Meteorological Society
Abstract: This study investigates the impact of a new satellite-derived wind product over the polar regions on ECMWF's global four-dimensional variational assimilation system. The winds are derived at the University of Wisconsin? ...
Eclipse Anomalies in Atmospheric Motion Vectors Derived from Meteosat Imagery and Their Implications on Data Assimilation
Publisher: American Meteorological Society
Abstract: This study examines atmospheric motion vectors derived by tracking features in image sequences from Meteosat for anomalies during the second satellite eclipse period of 2001. During eclipse periods (March?April; ...
Interactions of Dynamics and Observations in a Four-Dimensional Variational Assimilation
Publisher: American Meteorological Society
Abstract: A four-dimensional (4D) variational assimilation (4DVAR) seeks an optimal balance between observations scattered in time and space over a finite 4D analysis volume and a priori information. In some cases, 4DVAR is able to ...
Simplified and Regular Physical Parameterizations for Incremental Four-Dimensional Variational Assimilation
Publisher: American Meteorological Society
Abstract: A set of physical parameterizations has been developed for inclusion in incremental four-dimensional variational assimilation (4D-Var). The goal for this physical package is that it be simple, regular (for the efficiency ...
The Spatial Structure of Observation Errors in Atmospheric Motion Vectors from Geostationary Satellite Data
Publisher: American Meteorological Society
Abstract: This study investigates and quantifies in detail the spatial correlations of random errors in atmospheric motion vectors (AMVs) derived by tracking structures in imagery from geostationary satellites. A good specification ...
A Comparison of Variational and Ensemble-Based Data Assimilation Systems for Reanalysis of Sparse Observations
Publisher: American Meteorological Society
Abstract: An observing system experiment, simulating a surface-only observing network representative of the 1930s, is carried out with three- and four-dimensional variational data assimilation systems (3D-VAR and 4D-VAR) and an ...
The Role of Satellite Data in the Forecasting of Hurricane Sandy
Publisher: American Meteorological Society
Abstract: he excellent forecasts made by ECMWF predicting the devastating landfall of Hurricane Sandy attracted a great deal of publicity and praise in the immediate aftermath of the event. The almost unprecedented and sudden ?left ...
Assimilation and Modeling of the Atmospheric Hydrological Cycle in the ECMWF Forecasting System
Publisher: American Meteorological Society
Abstract: Several new types of satellite instrument will provide improved measurements of Earth's hydrological cycle and the humidity of the atmosphere. In an effort to make the best possible use of these data, the modeling and ...
ERA-20C: An Atmospheric Reanalysis of the Twentieth Century
Publisher: American Meteorological Society
Abstract: he ECMWF twentieth century reanalysis (ERA-20C; 1900?2010) assimilates surface pressure and marine wind observations. The reanalysis is single-member, and the background errors are spatiotemporally varying, derived from ...