QuikSCAT wind retrievals for tropical cyclones

The use of QuikSCAT data for wind retrievals of tropical cyclones is described. The evidence of QuikSCAT sigma(0) dependence on wind direction for >30 m/s wind speeds is presented. The QuikSCAT sigma(0)s show a peak-to-peak wind direction modulation of similar to1 dB at 35 m/s wind speed, and the amplitude of modulation decreases with increasing wind speed. A correction of the QSCAT1 model function for above 23 m/s wind speed is proposed. We explored two microwave radiative transfer models to correct the effects of rain for wind retrievals. Both radiative transfer models have been used to retrieve the ocean wind vectors from the collocated QuikSCAT and SSM/I rain rate data for several tropical cyclones. The resulting wind speed estimates of these tropical cyclones show improved agreement with the wind fields derived from the best track analysis for up to about 15 mm/h SSM/I rain rate. A comparative analysis of maximum wind speed estimates suggests that other rain parameters likely have to be considered for further improvements.