Estimation of Land Surface Temperature over the Tibetan Plateau Using AVHRR and MODIS Data

Estimation of large-scale land surface temperature from satellite images is of greatimportance for the study of climate change. This is especially true for the most challengingareas, such as the Tibetan Plateau (TP). In this paper, two split window algorithms (SWAs),one for the NOAA's Advanced Very High Resolution Radiometer (AVHRR), and the other for theModerate Resolution Imaging Spectroradiometer (MODIS), were applied to retrieve land surfacetemperature (LST) over the TP simultaneously. AVHRR and MODIS data from 17 January, 14 April,23 July, and 16 October 2003 were selected as the cases for winter, spring, summer, andautumn, respectively. Firstly, two key parameters (emissivity and water vapor content) werecalculated at the pixel scale. Then, the derived LST was compared with in situ measurementsfrom the Coordinated Enhanced Observing Period (CEOP) Asia-Australia Monsoon Project (CAMP)on the TP (CAMP/Tibet) area. They were in good accordance with each other, with an averagepercentage error (PE) of 10.5% for AVHRR data and 8.3% for MODIS data, meaning theadopted SWAs were applicable in the TP area. The derived LST also showed a wide range anda clear seasonal difference. The results from AVHRR were also in agreement with MODIS, withthe latter usually displaying a higher level of accuracy.