Coastal wind retrievals from corrected QuikSCAT Normalized Radar Cross Sections

A new correction scheme named “noise regularization”, aiming at mitigating land contamination in SeaWinds scatterometer coastal Normalized Radar Cross Sections (σ0s) is presented. The scheme is based on an analytical Cumulative Distribution Function (CDF) matching technique. Its efficacy is demonstrated in a semi-enclosed basin of the Mediterranean Sea, both in the σ0 and wind field domains. Wind biases along the coasts disappear and the sampling improves by a factor of 3 within the first 10 km from the coastline. This figure is likely underestimated because of a non-optimal tuning of the a-posteriori quality control tests in coastal areas.

Finally, wind retrievals are validated against those from a collocated Synthetic Aperture Radar (SAR) image acquired by the Envisat Advanced SAR (ASAR) offshore Norway. The agreement is very good in both speed and direction, and opens new perspectives on the use of SAR as a validation tool of coastal winds.