Validation of Himawari-8 and MTSAT-2 Sea-Surface Temperatures in the Western Tropical Pacific Ocean

Over several decades, the improvement of Sea-Surface Temperatures (SSTs) derived from satellites has been an area of focus in the scientific community. Knowledge of the accuracy of the SSTs is critical for climate and weather predictions and other research applications. In 2015, the Japanese MTSAT-2 geostationary satellite was replaced by the Himawari-8, which has higher spatial and temporal resolutions. In this study, data from both satellites were validated with subsurface in situ temperature measurements from the Tropical Atmosphere Ocean (TAO) array and self-recording thermometers at the depths of corals of the Great Barrier Reef, during a three-month overlap period when both satellites were operational. Results show that in general the Himawari-8 provides more accurate SST measurements compared to the MTSAT-2. At various in situ locations, the mean Himawari-8 SST error shows an improvement of ~0.15 K. Errors within the validation of the satellite with in situ SST fields were related to wind speed and diurnal heating. The improved accuracy of the Himawari-8 SSTs can benefit various studies within this region and in the wider area of the western Pacific and eastern Indian Oceans covered by Himawari-8.