Accuracy of Sea Surface Temperature from SMR of the HY-2B Compared with In-Situ Data in 2020

Haiyang-2B (HY-2B) is the second marine dynamic environment satellite of China. It carries several payloads, which includes a scanning microwave radiometer (SMR). Sea surface temperature (SST) is one of the main products of SMR. This study compares SST derived from SMR to in-situ SSTs in all of 2020. The collocations of HY-2B SRM and insitu SSTs were generated with the spatial window of 25km and the temporal window of 30 min, and the matchup data set includes 2696012 points from all over the global sea surface areas. Results show that SMR SST has a mean bias of 0.068°C (SMR minus buoy) and root-mean-square error (RMSE) of 0.851 °C in the global ocean area. By analyzing the global bias distribution map, we can conclude that the larger SST bias points mainly concentrated along the coast, sea ice, and high wind speeds areas where deteriorated the global overall accuracy performance. To prove it, three different areas were selected and analyzed separately. The results show that the RMSE in open ocean over mid and low latitudes is 0.66°C, while RMSEs in the nearshore zone and high wind speeds areas are 0.8°C and 1.1 °C, respectively.