The salinity gradient webpage is funded by NASA OSST and implemented and maintained by Earth & Space Research (ESR).  The goal is to provide a systematic estimation and assessment of satellite SSS gradients over the global ocean, including spatiotemporal variability and regional analyses.

Studies have shown that strong salinity gradients (fronts) are captured by satellite data from regional to basin-wide scales. Fine-scale salinity gradients can be observed and are useful for tracking high frequency ocean activities, such as Tropical Instability Waves (TIW) and the meandering of the Gulf stream. Seasonal variations of the salinity gradients (fronts) are also robust features in certain dynamically active regions, such as the Amazon outflow, under the intertropical convergence zone (ITCZ), and around western boundary currents. Therefore, salinity gradients (fronts) are useful for evaluating the capabilities of Aquarius, SMAP and SMOS-SSS data.


Data Descriptions

Horizontal salinity gradient data are generated from three satellites (Aquarius, SMAP and SMOS) and two Argo products (Scripps Institute Oceanography and IPRC). The datasets will include 4 variables: Sea Surface Salinity (SSS), total salinity gradient (∇S=√( ∇Sx^2+ ∇Sy^2 )), zonal salinity gradient and meridional salinity gradient. The monthly maps on global and regional scale will be able to view on the webpage and the daily maps will be able to be downloaded.


Salinity Gradient Retrieval Algorithm

For monthly data, salinity gradients are calculated directly from Level-3 SSS data.   For daily data, we’ll provide salinity gradients calculated both from Level-2 and Level-3 SSS data.



The salinity gradient data/figure will be updated each month with the most recent salinity maps available and with the release of each new version of satellite data.