夏季川西高原地表温度的空间特征和影响因素——以西昌市大部分区域为例

An analysis of land surface temperature(LST) and its influencing factors in summer in western Sichuan Plateau: A case study of Xichang City

揭示地表温度(land surface temperature,LST)的空间特征及其影响因素对环境变化研究具有重要意义。现有研究主要分析了单因子与LST的关系,但对向阳面和背阳面背景下多因子与LST的关系尚不清楚。研究中将区域划分为向阳面和背阳面,基于遥感数据提取土地利用信息并应用大气校正法进行LST反演,采用相关分析、主成分分析和逐步回归分析法构建LST与多因子(归一化湿度指数(normalized difference moisture index,NDMI)、归一化植被指数(normalized difference vegetation index,NDVI)、坡度(slope)、坡向(aspect)和数字高程模型(digital elevation model,DEM))的回归方程,研究了向阳面和背阳面背景下各因子对LST的影响程度。结果表明:相同海拔、土地利用的LST均表现为向阳面高于背阳面,LST随海拔升高而降低,不同土地利用的LST均不相同;向阳和背阳面LST的主要影响因素均为NDMI和DEM,向阳面NDMI影响程度最大,背阳面却相反;其余影响因子影响程度均较低,向阳面NDVI和背阳面Slope影响程度最大。因此,向阳和背阳面导致夏季川西高原LST空间格局变化,且其影响因子的影响程度和主次顺序差异明显。

Revealing the spatial characteristics of land surface temperature （LST） and its influencing factors is of great significance for environmental changes research. Many studies have examined the relationship between the single factor and LST, but the understanding of the influence of many factors on LST under the background of sunny slope and at the back of the light remains elusive. In this study, the authors divided the area into sunny slope and the back of the light, and retrieved LST based on atmospheric correction method, together with land use changes determined by using remote sensing data. The authors constructed the regression equation between the LST and many factors, such as normalized moisture index （NDMI）, normalized difference vegetation index （NDVI）, slope, aspect and DEM, for evaluating the influence on LST under the background of sunny slope and at the back of the light. The results show that LST in sunny slope was higher than that at the back of the light within the same elevation and land use, LST decreases with increasing altitude, and the LST in different land uses are not the same. The influencing factors of LST in sunny slope and at the back of the light were NDMI and DEM, the influence degree on NDMI under sunny condition is larger than that at the back of the light. The rest of the impact factors are low, the influence degrees under the sunny condition on NDVI and the slope at the back of the light were the largest. Therefore, the sunny slope and at the back of the light resulted in spatial pattern change of LST in western Sichuan plateau, and the influence degree of its impact factors has obvious primary and secondary order difference.