Improved high wind speed retrievals using AMSR and the next generation NASA Dual Frequency Scatterometer

Microwave scatterometer measurements are the standard for satellite ocean vector winds (OVW) measurements. Unfortunately, in extreme weather events, where high wind speeds are frequently associated with strong rain bands, precipitation can significantly degrade the OVW retrieval accuracy. This study addresses the feasibility of exploiting passive measurements to improve high wind speed retrievals for such extreme weather events. The Jet Propulsion Laboratory (JPL) has developed a conceptual design for a Dual Frequency Scatterometer (DFS) proposed to fly onboard the future Japan Aerospace Exploration Agency (JAXA) GCOM-W2 mission with the Advanced Microwave Scanning Radiometer (AMSR). These two instruments will provide a complimentary dataset of simultaneous and coincident active/passive measurements, which can correct for rain effects and thereby improve the OVW retrievals. End-to-end computer simulations are performed using the Weather Research and Forecasting (WRF) numerical weather model tuned to Hurricane Katrina (2005) for the 3D nature run (surface truth). Results show that the new OVW retrievals compare well to the nature run surface wind vectors and that this active/passive technique offers a robust option to extend the useful wind speed measurements range beyond the current operating scatterometers for future satellite missions.