中国大陆地表温度年变基准场研究

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

非构造活动或非地震因素对地表热辐射场(地表温度)的影响,对于利用卫星热红外遥感探索地震前兆抑或断层活动有着重要的现实意义.地表温度中,典型非构造活动或非地震因素成份有:由太阳辐射引起的稳定年周期成份和与地形、纬度及能量平衡等因素有关的长期稳定成份,合称年变基准场.本文根据2000-2008年的MODIS/Terra地表温度产品,利用小波分析提取了中国大陆地表温度的年变基准场.在此基础上,结合热传导方程和数学物理方法,获得了年变基准场的(半)定量化表达式.进一步,利用地表温度的长期稳定成份,获得了温度与海拔、纬度变化之间的定量关系:海拔每增加100 m,温度降低0.51±0.01 K;纬度每增加1°,温度降低0.77±0.08 K.总之,年变基准场可为利用热红外辐射提取地壳活动信息提供一种参考背景.温度与海拔、纬度变化之间的定量关系则可用来校正地形起伏和纬度变化对地表温度的影响.

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 0.51±0.01K 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.