An Analysis of SeaWinds Simultaneous Wind/Rain Retrieval in Severe Weather Events

• Main Author: Allen, Jeffrey R.
• Format: Others
• Published: BYU ScholarsArchive 2005
• Subjects: SeaWinds; QuikSCAT; scatterometer; weather radar; NEXRAD; rain detection; Simultanous Wind/Rain Retrieval; Electrical and Computer Engineering
• Online Access: https://scholarsarchive.byu.edu/etd/242; https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=1241&context=etd

Scatterometers, such as SeaWinds, can provide wide coverage of ocean surface winds. They estimate near-surface wind vectors by relating measured radar backscatter to a geophysical model function. However, SeaWinds measurements are also sensitive to rain, and conventional wind retrieval degrades in rainy conditions. An algorithm that exploits SeaWinds' sensitivity to both wind and rain has be developed. This algorithm, termed simultaneous wind/rain retrieval, retrieves both wind vectors and rain rates for a given ocean area. Instantaneous results of simultaneous wind/rain retrieval in Hurricane events is analyzed through comparison with the NEXRAD ground-based radar system. This comparison allows validation of retrieved rains. Additionally, conditions that affect the accuracy of SeaWinds wind/rain observations are evaluated. It is shown that, when thresholded, the rains retrieved by SeaWinds give an adequate rain flag. The comparisons of SeaWinds and NEXRAD rain estimates facilitate construction of a model to simulate variability in the SeaWinds rain estimates. The model is used to show that rain estimates are unbiased, though with significant variability. The variability is likely to be primarily driven by the noise inherent to the SeaWinds system.