Wind and wave observations off the south Pacific Coast of Mexico using TerraSAR-X imagery

Abstract

High-resolution TerraSAR-X images are analysed for the first time to investigate the effects of gap winds on the sea surface off the south Pacific Coast of Mexico. StripMap and ScanSAR scenes were acquired over the Gulf of Tehuantepec on March 2008, coinciding with a strong Tehuano event with a wind speed of about 24 ms-1. Although spatial variability of wind and wave parameters derived from the image analysis was fairly consistent with model data, Synthetic Aperture Radar (SAR)-derived wind speed was generally underestimated by 33%. The wave-retrieval algorithm, contrastingly, performed well enough to show evidence of shoaling and refracting ocean swell close to the shore. Furthermore, spatial evolution of image intensity spectral peaks suggests the presence of wave energy propagating to the SW, closely aligned with the offshore winds. Although further analyses are required, it could be the first time that growing waves in fetch-limited conditions have been detected through SAR remote sensing.