Authors: B. Gomez, H. Reich, A. Rhodin.
The data assimilation technique currently implemented at DWD is the 3DVAR. The background error is introduced as a fix matrix calculated using the NMC method. Ensemble data assimilation techniques will be used in the future in order to add flow dependent information on the background error and to provide initial conditions for probabilistic forecasts. LETKF, proposed by Hunt et. al (2007), provides a simple and fast algorithm to use an ensemble forecast to bring dynamical information to the analysis cycle. It also provides a full set of new ensemble members that are in agreement with the analysis update statistics. |
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