Performance evaluation of rain-corrected scatterometer winds in tropical cyclones

In 2003, the Japanese Midori-II spacecraft operated a microwave scatterometer (SeaWinds) and a microwave radiometer (AMSR). This unique instrument pairing has provided us the opportunity to better understand the impact of various sources of uncertainty on SeaWinds measured radar cross-sections such as attenuation, volumetric backscatter and rain roughening of the sea surface. A method for improving rain-contaminated scatterometer winds has been developed and applied to the SeaWinds data processing. We will present a summary of our rain correction algorithm and an analysis of differences between the rain-corrected and standard SeaWinds ocean vector winds in the tropical cyclone environment. Specific storm examples will also be shown, such as Fabian (2003) in which the corrected scatterometer wind field becomes asymmetric and more closely matches that of the NOAA Hurricane Research Division H*wind model output. More examples like Fabian are available for viewing within the DISCOVER Tropical Cyclone Archive available at http://www.discover-earth.org/visualizations.