SeaWinds Hurricane Wind Retrievals and Comparisons with H*Wind Surface Winds Analyses

This paper describes recent developments of an improved geophysical ocean wind vector retrieval algorithm that uses both active and passive measurements from QuikSCAT. This algorithm results in significant improvements in wind vector measurements in hurricanes and better rain-flagging of severely rain contaminated areas than does NASA´s standard wind vector product (L2B). By using a combined active/passive approach, we are able to infer wind estimates in the presence of light to moderate rain using the SeaWinds scatterometer. Rain effects (attenuation and volume scattering) are determined passively and then used to correct the measured ocean sigma-0 at 12.5 km wind vector cell resolution. Wind retrievals are performed using an improved geophysical model function (GMF) tuned for extreme wind events These ocean vector wind retrievals, known as Q-Winds, are compared with surface winds products from the NOAA Hurricane Research Division´s H^*Wind Analysis System, which assimilates near-simultaneous measurements from in-situ and remote sensors, such as, the Stepped Frequency Microwave Radiometer (SFMR), GPS dropsondes, and flight-level inertial navigation winds. Comparisons to H^*Wind are presented for Q-Winds and the SeaWinds Project´s new L2B-12.5 km ocean vector winds products.