下垫面参数与地表温度的时空差异性研究:以鄱阳湖流域为例

The spatio-temporal difference between underlying surface parameters and surface temperature: a case study of Poyang Lake basin

基于Landsat8 TIRS遥感影像数据,采用大气校正法反演鄱阳湖流域地表温度,分析了其不同时期(丰水期和枯水期)的温度分布特征;通过5种尺度下的网格化采样和空间统计,定量分析了鄱阳湖流域的地表温度(LST)空间聚集特征及其尺度效应;研究了不同时期下垫面参数与地表温度的相关性,揭示了鄱阳湖流域下垫面性质变化引起的温度变化特征。结果表明:鄱阳湖流域地表温度(LST)在丰水期和枯水期呈现不同的空间分布特征,且主要受鄱阳湖季节性水量的变化影响;其LST具有显著的空间聚集性和尺度效应,且其适宜的研究尺度为1 km;归一化植被指数(NDVI)、改进后的归一化水体指数(MNDWI)和归一化建筑指数(NDBI)与LST的相关性存在明显的季节性差异;鄱阳湖流域的地表温度具有显著的时空差异性,并且存在尺度效应;NDVI、MNDWI对温度具有抑制作用,NDBI具有升温作用,并且升温幅度大。

Based on Landsat8 TIRS remote sensing image data, the atmospheric correction method is used to invert the surface temperature of Poyang Lake basin and to analyze its temperature distribution characteristics in different periods(high water season and low water period);the spatial aggregation characteristics of surface temperature(LST) in Poyang Lake basin and its scale effects are quantitatively analyzed by cell sampling and spatial statistical analysis at five scales. The correlation between underlying surface parameters and surface temperature in different periods is studied, revealing the characteristics of temperature change caused by the change of subsurface properties in Poyang Lake basin. The results show that: the LST in Poyang Lake basin shows different spatial distribution characteristics during the high water season and low water season, which is mainly influenced by the seasonal water volume of Poyang Lake;the LST in Poyang Lake basin has significant spatial aggregation and obvious scale effect, and its suitable research scale is 1 km. Between the normalized difference vegetation index(NDVI), the improved normalized difference water index(MNDWI) and the normalized difference build-up index(NDBI) and LST showed significant seasonal differences. The LST of Poyang Lake basin has significant spatial and temporal variability and scale effect;NDVI and MNDWI have suppression effect on temperature, NDBI has warming effect and the warming magnitude is large.