Influence of Simulated Space-based Doppler Wind Lidar on TC Analyses and Forecasts

The lack of vertical wind profiles in the tropical atmosphere, particularly over the oceans, suggests that there is room for improvement in initializing numerical forecasts of tropical cyclones (TCs). Instruments that will be capable of measuring wind profiles include a spaceborne Doppler Wind Lidar (DWL). Earlier Observing System Simulation Experiments (OSSEs) have shown the potential for improving TC track forecasts as a result of assimilating simulated DWL data. This study expands on these previous efforts by investigating how the assimilation of idealized simulated DWL with different coverage patterns influences state-of-the-art numerical analyses and forecasts of TC track, intensity, and structure. Synthetic DWL observations were simulated from a high-resolution regional “Nature Run” of a hurricane and the tropical atmosphere, and assimilated using NCEP's Gridpoint Statistical Interpolation (GSI) scheme. Initial results from these 3d-Variational analyses and subsequent forecasts using the Hurricane Weather and Research Forecast (HWRF) regional model will be presented. Future goals of the study include conducting “trade studies” with different DWL configurations and error specifications, and combining DWL data with atmospheric motion vectors and surface wind observations such as those from the Cyclone Global Navigation Satellite System (CYGNSS).