Tobias Necker, LMU Munich, HErZ

Observation impact on the convection-permitting scale using an observation-based verification metric

Matthias Sommer, Martin Weissmann


Observation impact assessment offers a great potential for convective-scale data assimilation. It provides information on the contribution of various observations to the observing system and is crucial for the refinement of the observing network as well as the data assimilation system. In the framework of the Hans-Ertel Centre for Weather Research (HErZ), a method for an ensemble-based approximation of observation impact using an observation-based verification metric was developed over the past years. Instead of the subsequent analysis, the method uses subsequent observations for verification that are considerably more independent from the forecast. Furthermore, a peculiar property in the distribution of observation impact values is used to define a measure for the reliability of the estimate. Currently, the method is adapted to use independent observation types for verification. First results of the impact assessment using both radar-derived precipitation and integrated water vapor GPS humidity observations for verification are presented for the experimental convective-scale ensemble system of Deutscher Wetterdienst.

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