Enhancing Spatial Resolution of Sea Surface Salinity in Estuarine Regions by Combining Microwave and Ocean Color Satellite Data

In this letter, we propose a downscaling approach to improve the spatial resolution of sea surface salinity (SSS) in estuarine areas using combined microwave and ocean color data. The model established a relationship between SSS and normalized sea surface emissivity and colored dissolved organic matter (CDOM). The model was validated by in situ measurements conducted in the East China Sea (ECS) and Mississippi River Estuary (MRE). The model showed relatively good agreement with in situ SSS measurements and illustrated enhanced SSS at high (4 km) resolution compared with low (40 km) resolution, with root mean square errors (RMSEs) of 1.55 versus 2.58 psu in the ECS and 0.39 versus 1.49 psu in the MRE. Overall, the proposed downscaling approach enhances the spatial resolution and accuracy of satellite SSS observations over estuarine areas, which should be helpful for ocean dynamic and biogeochemical studies in these regions.

Automated summary

This study proposes an approach to improve the spatial resolution of sea surface salinity (SSS) in estuarine areas through the combination of microwave and ocean color data. The model establishes a relationship between SSS and normalized sea surface emissivity and colored dissolved organic matter (CDOM), which is validated through in situ measurements. The results show enhanced SSS at high resolution compared to low resolution, improving the accuracy of satellite SSS observations over estuarine areas.