Diagnosis of observation, background and analysis‐error statistics in observation space

Quarterly Journal of the Royal Meteorological Society - Tập 131 Số 613 - Trang 3385-3396 - 2005
Gérald Desroziers1, Loïk Berre1, Bernard Chapnik1, Paul Poli1
1Météo-France, Centre National de Recherches Météorologiques, Toulouse, France

Tóm tắt

AbstractMost operational assimilation schemes rely on linear estimation theory. Under this assumption, it is shown how simple consistency diagnostics can be obtained for the covariances of observation, background and estimation errors in observation space. Those diagnostics are shown to be nearly cost‐free since they only combine quantities available after the analysis, i.e. observed values and their background and analysis counterparts in observation space. A first application of such diagnostics is presented on analyses provided by the French 4D‐Var assimilation. A procedure to refine background and observation‐error variances is also proposed and tested in a simple toy analysis problem. The possibility to diagnose cross‐correlations between observation errors is also investigated in this same simple framework. A spectral interpretation of the diagnosed covariances is finally presented, which allows us to highlight the role of the scale separation between background and observation errors. Copyright © 2005 Royal Meteorological Society

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Quarterly Journal of the Royal Meteorological Society

Tập 131 Số 613

3385-3396

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