Impacts of an Airborne Doppler Wind Lidar on Tropical Cyclone Analyses and Forecasts

The initial structure of Tropical Cyclones (TCs) in models remains a limiting factor for TC forecasts. Instruments flown on NOAA's P3 Orion Hurricane Hunter Aircraft provide in situ inner core observations of Atlantic TCs. The Tail Doppler Radar provides the most comprehensive coverage of the wind field in TCs. TDR has the ability to measure winds in areas of precipitation, however, outside of these regions and below about 1 km, it either cannot make observations or the data is less reliable. Doppler Wind Lidar (DWL) was flown in two West Pacific typhoons in 2008. Pu et al. (2010) showed short-term improvements in TC track and intensity forecasts by assimilating DWL data in those cases. In August of 2015, an airborne DWL was flown for the first time on the P3 Orion into Atlantic Tropical Storms Danny and Erika. This study presents the first results demonstrating the impact of airborne DWL measurements on the numerical simulation of Tropical Storm Erika. Using the Hurricane Weather Research and Forecast (HWRF) model and different data assimilation systems, results show DWL data as a complementary observation set to data from the TDR.