Open AccessA Comparison of Variational and Ensemble-Based Data Assimilation Systems for Reanalysis of Sparse Observations
Author(s) -
Jeffrey S. Whitaker,
Gilbert P. Compo,
JeanNoël Thépaut
Publication year - 2009
Publication title -
monthly weather review
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.862
H-Index - 179
eISSN - 1520-0493
pISSN - 0027-0644
DOI - 10.1175/2008mwr2781.1
Subject(s) - data assimilation , assimilation (phonology) , computer science , variational analysis , algorithm , mathematics , meteorology , physics , philosophy , linguistics
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 ensemble-based data assimilation system (EnsDA). It is found that 4D-VAR and EnsDA systems produce analyses of comparable quality and that both are much more accurate than the analyses produced by the 3D-VAR system. The EnsDA system also produces useful estimates of analysis error, which are not directly available from the variational systems.