Loop Current and Eddy-Driven Salinity Variability in the Gulf of Mexico

Abstract

The Loop Current System, involving the Loop Current and Loop Current Eddies, is the principal circulation feature in the Gulf of Mexico, which exhibits salinity gradients due to Mississippi River system freshwater discharge and large salinity variability on seasonal timescales. This research uses satellite-derived sea surface salinity from NASA's Soil Moisture Active Passive and ESA's Soil Moisture and Ocean Salinity missions with altimetric sea surface height data to observe and quantify the redistribution of low-salinity water by Loop Current System interaction. Freshwater flux in this region during summer months is modulated by Loop Current System configuration as classified by three states. An extended Loop Current transports low-salinity water southward to the Florida Straits. A Loop Current eddy near the Louisiana-Texas shelf recirculates low-salinity water within the central Gulf. During a retracted Loop Current, no interaction occurs and low-salinity water remains close to the coast in the northern Gulf.