A study on the normal annual variation field of land surface temperature in China

Research on the influence of non-tectonic or non-seismic factors on thermal radiation of land surface has an important practical significance as to use the satellite thermal infrared remote sensing to explore seismic precursor or fault activity. In land surface temperature(LST), which may be obtained from satellite image, there exist two kinds of typical non-tectonic or non-seismic components as the following:the annual variation, produced by the solar radiation, and the longtime stable temperature, related with topography, latitude and energy balance on land surface. The sum of these two typical components is defined as normal annual variation field (NAVF) of land surface temperature. In this paper, the annual variation field of LST in China is extracted by using the method of wavelet, based on LST from 2000 to 2008. Then, theoretical equation of NAVF is gotten by heat theory and mathematic physical method. Furthermore, the quantitative relationships between temperature and altitude or latitude are obtained:temperature decreases 0. 51i0. 01K with altitude rising 100 m, and temperature decreases 0. 77±0. 08K with latitude rising 1 degree. In sum, NAVF may be used as a basic background to analyze anomaly of thermal radiation further, and the relationship between temperature and altitude or latitude could be used to revise effects of topography and latitude variations on LST.