A New Atmospheric Motion Vector Intercomparison Study

This study furthers a line of previously completed research regarding the similarities and differences between the operational Atmospheric Motion Vector (AMV) algorithms of various satellite-derived wind producers. By using a common set of MSG/SEVIRI images and ancillary data, past intercomparison studies assessed how the cloudy AMVs from each unique wind producer compared in terms of coverage, speed, direction, and cloud height (Genkova et al. 2008; Genkova et al. 2010). The current study focuses on including the CMA and NWC SAF AMV algorithms in the intercomparison in order to quantify its performance relative to other AMV algorithms, on updating the results of the previous AMV intercomparison studies due to the changes that have occurred since 2009, and lastly, on performing follow up studies, identified in the previous intercomparison work, to analyze particular issues in pursuance of a more complete understanding of how the different AMV algorithms compare. The study finds a mix of both positive and negative results. The different AMV algorithms successfully determine the horizontal and vertical displacements of the moved features, but not all centers define a consistent AMV speed and direction with these displacements. Using the IR brightness temperature (TBT ) for the height assignment, the distribution of AMV heights is highly variable due to the variability of how this representative T BT is defined. When additional height assignment techniques are used, all centers except JMA improve the AMV validation statistics. Nevertheless, the improvement is limited for some of the centers because of using the improved height assignment techniques in only a small part of the data. The two centers using CCC height assignment method (EUM and NWC) are in general the ones obtaining the best validation statistics. Considering the AMV coverage, important differences occur between centers even in the case where a similar prescribed configuration is used. This paper is a summary of the full AMV intercomparison Technical Report which can be found at: www.nwcsaf.org/HD/files/vsadoc/CIMSS_AMV_Comparison_FinalReport_04July2014.pdf .