Measuring coastal sea-surface salinity of the Louisiana shelf from aerially observed ocean color

Abstract

We have demonstrated the ability of airborne radiance and irradiance sensors to detect the persistent salinity gradient of the Atchafalaya plume and corresponding color fronts as observed by in-situ shipboard measurements as well as STARRS. We used an empirical algorithm Acdom (412) =3D 0.227}(Rrs510/Rrs555)^−2.022 (1) for CDOM from D'Sa et al. 2006. Their study was conducted in the same region (Louisiana Shelf) and time of year (March) as our study and it was performed with similar optical equipment. This study resulted in an Ocean Color Salinity model that can measure with ~88% accuracy the Sea-Surface Salinity of the Louisiana shelf. A multi-linear regression for salinity, based on two of the optical channels, provides an excellent qualitative proxy for large scale coastal salinity in the Atchafalaya plume region (y=−3D0.0082⋆x+0.34, R²=3D0.90, n=3D5220). We then developed two algorithms from the May and November data. This was done to create two seasonal equations for salinity.