High impact weather study using advanced IR sounding data

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 severe thunderstorms. 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 and Advanced Baseline Imager (ABI) like radiances. Temperature and moisture profiles were further retrieved from these radiances. The derived atmospheric stability parameters (eg., lifted index) show that the ABI or current GOES sounder only provides limited stability information before the storm development due to the limited spectral information for temperature and water vapor profiling, while the advanced IR sounder (HES like) can provide the critical unstable information well earlier than ABI or current GOES sounder. In the second part of this study, the high spatial resolution of single field of view (SFOV) atmospheric soundings from AIRS, a research product from CIMSS/UW-Madison, have been applied to the hurricane track and intensity assimilation and 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 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 data are added.