A Comparison of Two Atmospheric Motion Vector Derivation Schemes: the Eumetsat Msg Prototyping Scheme and the Nsmc Scheme

In order to examine the effectiveness of the NSMC scheme, a comparison was arranged under the cooperation frame between EUMETSAT and CMA (China Meteorological Administration). Two periods of data from Meteosat-5 including IR and WV channels were processed and compared by both the EUMETSAT and NSMC schemes. The comparison periods were one week long each, and in January and July respectively. The comparison results show that EUMETSAT AMVs with QI above 0.90 have the least difference compare to ECMWF model output and radiosonde reports. But EUMETSAT AMVs with QI above 0.90 holds less data. NSMC AMVs are closer to ECMWF model output and radiosonde reports than EUMETSAT AMVs with QI above 0.6 and 0.75. In case the two schemes giving different height assignment at IR channel or giving different tracking results, NSMC AMVs are closer with ECMWF model output than EUMETSAT AMVs with QI above 0.6 and 0.75. The NSMC scheme supplies high density AMVs with good quality. This is because the NSMC scheme takes procedure to distinguish high and low clouds before height assignment and takes quality control and optimisation at both tracking and horizontal consistency examining components.