Validation of MODIS Sea Surface Temperature Product in the Coastal Waters of the Yellow Sea

Abstract

Sea surface temperature (SST) plays a fundamental role in the exchange of heat, momentum, and water vapor between atmosphere and ocean. Therefore, measurement of SST has been done from ships, buoys, offshore platforms, and satellites. During past decades satellites are being increasingly used, because datasets over wide areas can be obtained. In this paper, moderate resolution imaging spectroradiometer (MODIS) on board Terra and Aqua SST products were examined and validated for coastal waters in the Yellow Sea by using the in situ buoy data. A strict match-up method was adopted in view of the complexity and variability of coastal area, resulting in 154 and 164 match-ups for Terra and Aqua, respectively. The MODIS SST agreed well with in situ buoy SST, with squared correlation coefficients R2 of 0.989 for Terra, and 0.987 for Aqua. Relative to in situ SSTs, the satellite-derived SSTs had a bias of 0.23 °C and 0.06 °C, a standard deviation of 0.79 °C and 0.85 °C, and a root mean square error of 0.83 °C and 0.85 °C, for Terra and Aqua. The differences between MODIS and in situ SST exhibited apparent seasonal variations. The accuracy of MODIS SST products for spring and summer were lower than those for autumn and winter, which could be caused by frequent sea fog along the southern coast of Shandong Peninsula. The SST bias approximately depended on wind velocity; low wind velocity could enhance the diurnal SST amplitude and the bulk-skin temperature difference. However, there is no significant dependence of the bias on air-sea temperature difference or surface flow velocity.