Wednesday, 26 January 2011
Washington State Convention Center
A high spectral resolution Infrared (IR) sounder in the geostationary orbit will provide unique high temporal and high spatial resolution 3-dimensional temperature and water vapor profiles. This will help monitor and forecast the high impact weather such as severe thunderstorms and tropical storms. In this study, a case from the International H2O Project (IHOP) field experiment was used to demonstrate the benefit of advanced IR geo-sounder in nowcasting severe storms. Atmospheric profiles from the output of high resolution Weather and Research Forecasting (WRF) model were used to simulate the Hyperspectral Environmental Suite (HES) like. Temperature and moisture profiles were then retrieved from these radiances using CIMSS hyperspectral IR sounding retrieval (CHISR) algorithm. The derived atmospheric stability parameters (e.g., lifted index) show that the HES like sounder can provide the critical unstable information 3 ~ 4 hours earlier than the regional numerical weather prediction (NWP) forecast (e.g., the rapid update cycle - RUC), also HES provide warning information 7 ~ 8 hours earlier than the radar observations. We also use the Atmospheric InfraRed Sounder (AIRS) and Infrared Atmospheric Sounding Interferometer (IASI) as precursor for storm short range forecast through assimilating the advanced sounding product. The full spatial resolution atmospheric soundings from AIRS and IASI have been applied to the hurricane track and intensity forecast by using NCAR WRF Data Assimilation Research Testbed (DART) ensemble assimilation system. The results show that the track errors for both Hurricanes Ike (2008) and Sinlaku (2008) are greatly reduced when full spatial resolution AIRS and IASI soundings are assimilated. The intensity forecast of hurricane Ike and the rapid intensification of typhoon Sinlaku are also significantly improved if high spatial resolution AIRS and IASI data are added. Experiments also show that water vapor soundings play more important role the temperature soundings in hurricane forecast. This study demonstrates the advantage of future geostationary advanced IR sounder on storm nowcasting and short range forecasting.
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