Assimilation of high-latitude winds from MODIS (Invited Presentation)

Feature-tracking winds based on imagery obtained from geostationary orbit have been widely used by the NWP community for more than a decade. One important shortcoming of these data is the lack of coverage in the high latitudes that are seen poorly or not at all from these orbits. Recently, the feature tracking algorithms have been modified and applied to high-latitude imagery from polar orbiters, in particular to observations obtained from NASA’s two MODIS instruments flying on Terra and Aqua. The MODIS wind product has been widely studied and tested, and the results have generated a substantial amount of interest in high-latitude satellite winds among NWP centers. In this presentation we will provide an overview of the role of these winds in the data assimilation systems. Impacts on forecast skill will be shown, both in an average sense and from individual cases. Similarities and differences between the impacts in the two hemispheres will be shown. The relative roles and contributions of water vapor images and IR cloud images will be discussed. Finally, the implications of the MODIS results for the global observing system of the future will be addressed.