Yang ZongRu , Bai XueZhi , Ma Gang , Dai QiuDan , Zhang BangLin , Zhang Peng
2023-12-01 CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION 2023 66(卷), 12(期), (4875-4888页)
To obtain the land surface temperature synchronized with the satellite microwave observation is the key to successful assimilation of all-surface ground-based microwave radiometer data. In order to further improve the accuracy of ATMS near-surface channel forward simulation on complex underlying surfaces, and in view of the problem that ATMS SDR data and VIRR inversion product data cannot be synchronized, this paper realizes the cross-matching of observation data between satellite sequences based on pixel matching technology, and uses the inversion surface temperature across the spectrum as the lower boundary parameter of the observed radiation in the forward ATMS near-surface channel. Then, error analysis and verification were carried out on the forward radiation, simulation values based on ERA5 surface temperature, and typical underlying surface detection data, providing technical support for the assimilation of the ATMS near-surface channel in the next step. In the matching process of FY-3D HIRAS pixel and MERSI-II pixel, convolution can reduce the deviation between the weighted average observed radiation of the HIRAS channel and the MERSI-II radiation, and the average error is about 0.28 K. The temporal evolution trend of the average deviation and STD between the daytime and nighttime HIRAS convolved brightness temperature and MERSI-II channel brightness temperature are quite similar. When matching FY-3D MERSI-II pixel with NOAA-20 CrIS pixel, the pixel matching accuracy between mid-latitude and polar orbiting satellite sequences is comparable to the matching accuracy between polar orbiting satellites and geostationary satellites in mid-low latitudes in GSICS, and the deviation of the window-brightness temperature after matching is about 0.1 K. This indicates that the pixel matching method among satellites in GSICS can be used under more extensive conditions. Compared with ERA5 surface temperature, the deviation between the surface temperature inverted by MERSI-II in desert areas and the surface temperature measured by the station is smaller. The simulated brightness temperature of surface temperature inverted by MERSI-II can better show the real situation of Channel 5 brightness temperature of ATMS. Although surface temperatures inverted based on infrared observation and microwave observation represent soil temperatures at different depths, it is considered that the two types of surface temperature can be substituted for each other when the error is less than a certain threshold, and will not have a significant impact on the forward simulation of satellite microwave near-surface detection channel. At this time, the surface temperature inverted based on infrared observation can be regarded as the embodiment of the surface temperature of microwave spectrum under a certain error level.