Mesoscale and Submesoscale Eddy Identification in the Gulf of Mexico Using Sea Surface Temperature

Since the 2010 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Deepwater Horizon</i> oil spill, submesoscale processes in the Gulf of Mexico (GoM) have grown in importance alongside discoveries regarding oil dispersion, hurricane intensification, and primary productivity. Satellite-derived high resolution Sea Surface Temperature (SST) products can identify submesoscale eddies (<25 km radius). To leverage this high resolution data, two eddy tracking algorithms were compared using two different SST products. These algorithms, Contour Tracing (CT) and Temperature Thresholding (TT), were applied to Optimum Interpolation Sea Surface Temperature (OISST, 1/4° resolution) and Operational Sea Surface Temperature and Ice Analysis (OSTIA) SST (1/20° resolution). OSTIA, with a higher resolution than OISST, consistently identified more submesoscale and mesoscale eddies. Both algorithms performed best during the winter, as SST gradients across the GoM were stronger during this time. The TT algorithm identified more submesoscale eddies during wintertime than the CT algorithm with OSTIA. In conclusion, higher resolution OSTIA with the TT algorithm performed best at identifying submesoscale and mesoscale eddies. While altimetry-derived Absolute Dynamic Topography (ADT) is commonly used in eddy tracking algorithms, recent studies have used ocean color Chlorophyll-a (Chl-a) as well in identifying eddies. The TT algorithm can be used for eddy tracking in any region with ADT and Chl-a if threshold values are identified.