Investigation of Submesoscale Eddies from Modis Color Index Products in Coastal Regions: A Case Study in Subei Shoal.

The investigation of submesoscale coastal eddies requires the products of high spatiotemporal resolution. MODIS color index (CI) products can improve spatial coverage in coastal regions to detect submesoscale signals, when observations of high-frequency radars are limited in small areas. In our study, a gradient parameter derived by CI images is used to identify submesoscale eddies by the eddy detection algorithm based on the vector geometry in the case of Subei Shoal. The results show that gradient parameters have the ability to detect submesoscale eddies. The mean radius values of anticyclonic and cyclonic eddies are 1.85 and 1.56 km, respectively. This method makes it potentially useful for investigations of ecosystem distributions in other coastal regions.