Ana Fernandez del Rio , Deutscher Wetterdienst (DWD)
Data Assimilation for NWP with the ICON Global Model
Coauthors
Andreas Rhodin, Alexander Cress, Harald Anlauf, Robin faulwetter, Jaison Ambadan, Roland PotthastAbstract:
The ICON (ICOsahedral Nonhydrostatic general circulation) global model was developed jointly by the German Weather Service (Deutscher Wetterdienst, DWD) and the Max Planck Institute for Meteorology (MPI-M), and is used operationally for Numerical Weather Prediction (NWP) at DWD since January 2015. A hybrid En-Var data assimilation scheme has been developed, and it replaced the previous deterministic 3D-Var in operations in January 2016. The current system, which uses a Local Ensemble Transform Kalman Filter (LETKF) to make the uncertainty flow dependent, will be described. The three data assimilation methods (deterministic 3D-Var, ensemble based LETKF and hybrid En-Var system combining both) will be compared, illustrating how they work differently and assessing the performance of medium range forecasts in a fully operational setup.