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The direct assimilation of cloud‐affected satellite infrared radiances in the ECMWF 4D‐Var
Author(s) -
McNally A. P.
Publication year - 2009
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.426
Subject(s) - overcast , radiance , radiosonde , meteorology , environmental science , satellite , data assimilation , remote sensing , cloud computing , cloud cover , computer science , sky , geography , engineering , aerospace engineering , operating system
A system has been developed to make use of infrared radiance data in cloudy conditions. The central strategy is to extend the 4D‐Var analysis control vector to include parameters which describe the cloud conditions and simultaneously estimate these parameters together with temperature and humidity inside the main analysis. In the current prototype configuration of the system, the extra cloud variables are decoupled from the model physics and only cloudy data in completely overcast conditions are used. Early experiments with the new system have produced some encouraging results. Additional use of overcast radiance data improves the analysis fit to independent radiosonde observations and results in some small, but statistically significant, improvements in forecast quality. Copyright © 2009 Royal Meteorological Society