Validation of Land Surface Temperature Derived from 37-GHz AMSR-E over Northern China

A validation study of land surface temperature (LST) obtained from the Ka band (37 GHz) vertically polarized brightness temperature over northern China is presented. The remotely sensed LST derived jointly by the Vrije Universiteit Amsterdam and the NASA Goddard Space Flight Center (VUA-NASA) from the Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) were compared to the daily in-situ top soil temperature/infrared surface temperature observations from eleven/three Enhanced Coordinated Observation stations in arid and semi-arid regions of northern China. The VUA-NASA LST from the descending path exhibited a stronger correspondence to the in-situ infrared surface temperature than soil temperature observations, whereas correlations (R2) of the latter ranged from 0.41 to 0.86. Meanwhile, the ascending overpass LST was generally warmer than the in-situ soil temperature observations at all stations, and the correlation (R2) was between 0.07 and 0.72. Furthermore, the correlation of the descending path was generally greater than that of the ascending path at the same station. The descending path VUA-NASA LST was sensitive to precipitation and presented good agreement with ground temperature dynamics. The analyses demonstrated that the descending overpass LST was reliable to reflect reasonable patterns of temperature dynamics for land surface temperature in the region.