Sub-Mesoscale Eddy Detection from Sentinel-1A SAR Image: A Case Study Along Vizag Coast

Abstract

Oceanic eddies are important ocean surface features and play a crucial role in ocean energy transfer, nutrient distribution and biological production in the global ocean. Sub-mesoscale eddies are characterized by their small spatial scales (<100km) and short temporal scales (hours to days). Large mesoscale eddies are detected using satellite altimetry data where as sub-mesoscale eddies are detected using Synthetic Aperture Radar(SAR) images of high resolution. This paper analyses two such eddies captured in a SAR image off the coast of Vizag. The SAR image is despeckled and thresholded to extract the eddy features. The eddy images are analysed and validated using Sea Level Anomaly(SLA) and Chlorophyll-a datasets in order to understand the eddy dynamics and its characteristics.