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利用两期TM数据对塔里木河上游典型绿洲的地表温度进行反演,并查询实时陆面地表温度进行了对比检验,其差值均在1.5℃以内。在此基础上,分析了不同时期塔里木河上游典型绿洲的温度时空变化,结果表明:(1)2007～2011年,下垫面温度主要集中在18～51℃,其中,水体温度在18～24℃(低温区),耕地地表温度在24～29℃(中温区),林地地表温度在29～36℃(偏高温区),绿洲周边的裸地地表温度在36～42℃(高温区),远离绿洲的荒漠地带地表温度在42～51℃(极高温区);(2)2007～2011年,水体地表温度平均增高0～4℃,植被地表温度平均增高0～12℃,绿洲周边的裸地地表温度平均增高0～7℃,远离绿洲的荒漠地带地表温度平均增高0～9℃。其中林地对温度的变化影响较大。总之,地表温度呈现沿中心逐渐向四周增高的分布规律,表现出明显的“冷岛效应”。此研究对进一步理解塔里木河上游绿洲土壤-植被-大气系统能量交换状况以及我国西北干旱、半干旱区域地表热量分布差异特征具有重要的意义。
Using two TM data, the surface temperature of the typical oasis in the upper reaches of the Tarim River was inverted and the real-time land surface temperature was inquired and compared. The differences were all within 1.5 ℃. On this basis, the temporal and spatial variations of temperature in the typical oases in the upper reaches of the Tarim River at different periods are analyzed. The results show that: (1) From 2007 to 2011, the underlying surface temperature mainly lies in 18 ~ 51 ℃, of which the water temperature is in the range of 18-24 The surface temperature of cultivated land is in the range of 24 ~ 29 ℃ (middle temperature), the surface temperature of forest land is in the range of 29 ~ 36 ℃ (high temperature), the surface temperature of bare land around the oasis is in the range of 36 ~ 42 ℃ (high temperature) (2) From 2007 to 2011, the surface temperature of the water body increased by 0 ~ 4 ℃ on average, and the surface temperature of the vegetation increased by 0 ~ 12 ℃ on average. The nudges around the oasis Surface temperature increased by an average of 0 ~ 7 ℃, the surface temperature of the desert far away from the oasis increased by 0 ~ 9 ℃ on average. Among them, the woodland has a great influence on the temperature change. In short, the surface temperature showed a gradually increasing around the center of the distribution, showing a clear “cold island effect.” This study is of great significance to further understand the energy exchange status of the soil-vegetation-atmosphere system in the upper reaches of the Tarim River and the differences in surface heat distribution in the arid and semi-arid regions of northwestern China.