Application of ocean colour satellite sensors to mapping sea surface salinity (SSS) around Korean coastal waters

Abstract

Estimation of ocean surface salinity from space has widely been tried mainly by passive microwave sensors such as Soil Moisture and Ocean Salinity (SMOS), Aquarius. But, the results are not satisfactory in the coastal waters due to their rough spatial resolutions. Recent enhanced technologies of ocean colour satellite sensors in terms of spatial and temporal resolution can be employed effectively to the mapping of sea surface salinity (SSS), in particular in the coastal waters, although it is still challenging. As SSS can be a good indicator of short- or long-term changes in ocean environment and consequently the climate changes, many attempts have been made to mapping SSS in the wide area of ocean surface, although little has been successful particularly in the coastal area. Although it is well-known that coloured dissolved organic matter (CDOM) absorption property has a strong correlation with SSS in the area that influenced by freshwater inflow, it is not an easy task to retrieve accurately the CDOM absorption in highly turbid coastal waters due to the non-algal particle from land. In this study, remote sensing reflectance (Rrs) from the Geostationary Ocean Colour Imager (GOCI)centred at 490 nm (band 3), 555 nm (band 4), 660 nm (band 5) have been employed and validated to map SSS in the mid-western coastal area of Korean peninsula. Empirical relationships between Rrs at three bands and SSS are derived from in-sit