Model Derived Sea Surface Salinity Subfootprint Variability in the North Arabian Sea and Western Pacific
[28-Aug-2018] D'Addezio, J.M. and Bingham, F.M.
Presented at the 2018 Ocean Salinity Science Team and Salinity Continuity Processing Meeting
Submesoscale resolving simulations of the North Arabian Sea and western Pacific using the Navy Coastal Ocean Model (NCOM) for 2016 were examined to estimate sea surface salinity (SSS) subfootprint variability (SFV). Footprint sizes of 10 km, 20 km, 40 km, and 100 km were tested. The high-resolution model grids were partitioned into regularly spaced, larger subdomains to simulate each footprint size. SFV was quantified by the annual median SSS standard deviation within each of the respective subdomains. For the 10 km and 20 km footprint sizes, the SFV is greater than 0.2 psu along the continental shelves where strong salinity fronts are present. For these footprint sizes, open ocean SFV is small (~0.02 psu). Using a 40 km footprint, the continental shelves again contain the highest variability but open ocean values are larger, approximately 0.1 psu. This trend continues with respect to the 100 km footprint, with open ocean SSS SFV approaching 0.2 psu. These results suggest that SFV is generally high near the coast. Open ocean submesoscale processes of size 10-20 km do not substantially contribute to SSS SFV. Instead, strong horizontal stirring induced by surface mesoscale eddies with 40-100 km scales contribute most substantially to the open ocean SSS SFV.