(Sub)Mesoscale Salinity Variability at Fronts

As the resolution of observations and models improves, emerging evidence indicates that ocean variability on spatial scales of O(1km) (i.e.,the submesoscale) is of fundamental importance to ocean circulation, air-sea interaction, and bio-geo-chemical cycling. Our recent work has shown that, in many regions, salinity variability dominates over temperature variability in forming submesoscale (and mesoscale, O( 10 – 100 km)) density fronts. The motivation of the proposed work is the need to better characterize surface density variability, and in particular the role of salinity, across the submesoscale to mesoscale range (the “(sub)mesoscale”).

Current satellite technology does not allow for the observation of submesoscale features in sea surface salinity (SSS). However, submesoscale variability can be detected in satellite measurements of sea surface temperature (SST) and ocean color (OC). Aquarius, at about 100 km resolution, revealed an unexpected wealth of lateral ocean salinity structure so we expect to begin resolving mesoscale structures in SSS. Our research is further motivated by the need to both develop techniques to exploit satellite salinity measurements in order to extract signals with the highest possible spatial resolution and to quantify the sub-pixel salinity resolution that is not captured by satellites.

We use a variety of in situ and remote data to identify and characterize the distribution of these fronts and their possible implications on ocean dynamics.