摘要
利用Landsat-5TM影像,采用辐射传导方程对三峡库区腹地的地表温度进行了反演。在辐射传导方程中,对于地表比辐射率的估算,考虑到库区腹地复杂的地形和地表覆被类型的多样性,采用结合地形、水、建筑和自然表面等因素作用的经验公式进行。结果表明:①地表温度随海拔的升高呈降低趋势,其空间展布与山脉走向一致;②不同的地表覆被格局下,近地面水热交换差异较大,地表温度作为其中重要的参数也展现出显著的异质性,呈现建筑>自然表面>水体的基本格局。在相同海拔高度下,地表温度的高低主要取决于地表覆被的类型及其转换;③同一覆被类型间在不同海拔下的地表温度间的变化幅度因覆被类型的不同而差异显著,但随海拔的升高而降低具有显著的垂直变化规律;④验证点反演出的地表温度均是介于最低与最高气温之间的,与植被覆盖度较高区域的地表温度和气温间的关系非常接近。奉节和万县的地表温度反演值均显著高于相应站点同日平均气温,尤其是万县站高出值达7.46℃,主要源于站点位于城区内部,地表覆被中建筑所占比重较大,使得反演值明显高于日平均气温。地表温度的遥感反演值符合地表水热关系和垂直温度梯度规律。
Land surface temperature（LST）was retrieved from Landsat Thematic Mapper（TM） images in the hinterland of the Three Gorges Reservoir based on the radioactive transfer equation. In the radiation transfer equation,estimation of land surface emissivity was carried out by empirical formulas integrating the function of terrain,water,construction,and natural surface into land surface temperature retrieval by taking into account complex topography and diversity in surface cover types in the hinterland of the Three Gorges Reservoir Area.Results show 1）LST exhibits a decreasing tendency with increasing elevation.In general,human disturbance was relatively less in higher altitude and regions with rolling topography.Solar radiation received was converted mostly into latent heat rather than sensible heat flux.LST was lower over these areas;2） Large differences in land surface water and heat exchanges occurred under different patterns of land cover.LST exhibited high spatial variability,with a descending order as following： constructionnatural surfacewater.At the same altitude,LST highly corresponded to land cover type and their conversions.At 200 m elevation,the LST retrieval of building was the highest,up to 29.87℃,followed by that of the natural surface with 26.53℃,and the lowest was 22.69℃for water cover;3）Magnitudes of changes in LST at different elevations show marked differences due to differing land over types.However,LST decreased with increasing altitude,showing significant vertical variations.LST of natural land cover types was only 16.42℃at the highest elevation.LSTo f buildings was 27.03℃at the highest elevation;4）LST retrieved at sampling points ranged between the minimum and maximum temperature.LST seems to be closely related to air temperature.These values of LST retrieved in both Fengjie and Wanxian were significantly higher than the average temperature of the corresponding site for the same day.In particular,the LST retrieval was 7.46℃higher than the average temperature in Wanxian for the same day.
出处
《资源科学》
CSSCI
CSCD
北大核心
2012年第2期256-264,共9页
Resources Science
基金
重庆市自然科学重点基金项目:"基于库周气象数据的三峡水库地表覆被变化气候效应的情景模拟"(编号:2010JJ0069)
重庆师范大学校立基金重点项目:"三峡库区地表覆被陆水界面转换气候效应的数值模拟"(编号:10XLZ002)
