High-Resolution Coastal Winds From the NOAA Near Real-Time ASCAT Processor

The NOAA near real-time operational advanced scatterometer (ASCAT) ocean surface wind vectors are produced at 12.5- and 25-km swath grid resolutions. To avoid land contamination due to the relatively large footprint size, the wind data in the inner most coastal regions (
$\sim $
15–25 km from the coast) are excluded from the final product. To obtain more retrievals in the coastal regions, we utilize measurements containing up to 50% land contribution ratio (LCR) and employ a combination of the enhanced resolution processing technique and a coastal normalized radar cross Section (NRCS) correction method to achieve accurate wind retrievals to be within
$\sim $
1.0–2.5 km of the coast. The backscatter correction is implemented for each ASCAT coastal zone measurement. The mean and standard deviation of the land contribution for each measurement are determined, and then, the land backscatter contribution is subtracted out from the actual measurement through an iteration method to estimate the ocean-only signal. An ocean calibration of the enhanced resolution backscatter was implemented before the wind retrieval step to improve the accuracy. Finally, an LCR ranking is implemented after the wind retrieval to further remove the remaining land contamination residuals. Additional quality control is also developed. The high-resolution coastal winds from ASCAT are validated against a variety of other independent wind measurements. The results are then presented and discussed.