UMD AOSC Alumni Seminar
Tropical Weather Systems within a Global Data Assimilation and Forecasting Framework
Dr. Oreste Reale
NASA Goddard Space Flight Center
Laboratory for Atmosphere
State-of-the-art operational analyses and reanalyses, on time scales ranging from weather to seasonal, provide a substantially different depiction of the African Easterly Jet (AEJ), which controls the meteorology of the tropical northern Atlantic. Large discrepancies can also be detected in the atmospheric circulation over the tropical Pacific and in the analysis of tropical cyclones (TCs). In particular, observed TCs can be completely missed in the operational analysis.
Improvements stemming from a more accurate representation of the thermal structure of the atmosphere, as provided by the NASA Atmospheric Infrared Sounder (AIRS), are discussed. However, results suggest that a greater impact from AIRS is obtained if data in presence of clouds are not entirely rejected, as happens when assimilating clear-sky radiances only. Assimilation of cloudy AIRS retrievals can consistently produce better TC analysis and forecast track than clear-sky radiances, at any given resolution, and on all basins. Analysis and forecast of extreme precipitation originated from TCs or monsoonal depressions are also affected by the strategy adopted to assimilate AIRS data. Finally, some recent results consequent to the implementation of interactive aerosol in a global forecast system indicate that a more realistic treatment of Saharan dust also improve the analysis and forecast over the tropical Atlantic region.
May 5, 2011, Thursday
AOSC 818. Frontiers in Atmosphere, Ocean, Climate, and Synoptic Meteorology Research