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A 4D‐Var re‐analysis of FASTEX
Author(s) -
Desroziers G'erald,
Hello Gwena'elle,
Thépaut JeanNoël
Publication year - 2003
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 - 10.1256/qj.01.182
Subject(s) - climatology , storm , data assimilation , meteorology , range (aeronautics) , environmental science , geology , geography , materials science , composite material
A complete re‐analysis of the Fronts and Atlantic Storm‐Track EXperiment (5 January–27 February 1997) is performed. It provides a reference description of the life cycle of an ensemble of cyclogeneses over the north Atlantic. Many aspects make this re‐analysis noteworthy. In particular, the FASTEX period is characterized by an exceptional increase in the number of dropsoundings or radiosoundings concentrated on the storm track. Another striking point of the re‐analysis is the use of a four‐dimensional variational (4D‐Var) assimilation scheme on such a long period associated with the French Arpège (Action des Recherche Petite Echelle et Grand Echelle) global stretched model, that allows a locally high resolution in the area where dense networks of dropsondes were deployed. A twin re‐analysis with the same characteristics but without any FASTEX data is also performed. It shows that the impact of the special FASTEX data is quite noticeable in the resulting analyses and is lower, but still perceptible, in the associated short‐range forecasts (6 h–36 h). The impact of FASTEX observations on a particular FASTEX case is also shown. Copyright © 2003 Royal Meteorological Society