MODIS-based estimation of air temperature of the Tibetan Plateau
MODIS-based estimation of air temperature of the Tibetan Plateau
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DOI：
10.1007/s11442-013-1033-7
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发表时间：
2013-06
影响因子：
4.9
通讯作者：
Yong-hui Yao;Bai-ping Zhang
中科院分区：
文献类型：
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作者：
Yong-hui Yao;Bai-ping Zhang
青藏高原是欧亚大陆乃至世界的重要热源，它的巨大和高耸深深地影响着欧亚大陆乃至世界的气候。然而，由于缺乏气象观测站和非常有限的气候资料，很少有定量的了解青藏高原的加热效应和温度模式。利用2001-2007年的MODIS地表温度（LST）数据，结合137个测站的气象资料和ASTER GDEM数据，对青藏高原及其邻近地区月平均气温的空间分布进行了估算和制图。对月平均气温（Ta）与月平均地表温度（Ts）进行时间序列分析，并进行普通线性回归（OLS）和地理加权回归（GWR）。回归分析表明，Ta与Ts有较好的相关性，以MODIS Ts和海拔高度为自变量的GWR估计结果比OLS估计的结果好得多，校正R2> 0.91，RMSE = 1.13-1.53°C。对于80%以上的台站，由此从Ts反演的Ta具有低于2°C的残差。对反演的Ta资料的时空格局分析表明，在海拔4500 m的7月（最热月份），平均气温可达10°C。这可能有助于解释为什么北方最高的树带界线在青藏高原。
The immense and towering Tibetan Plateau acts as a heating source and, thus, deeply shapes the climate of the Eurasian continent and even the whole world. However, due to the scarcity of meteorological observation stations and very limited climatic data, little is quantitatively known about the heating effect and temperature pattern of the Tibetan Plateau. This paper collected time series of MODIS land surface temperature (LST) data, together with meteorological data of 137 stations and ASTER GDEM data for 2001–2007, to estimate and map the spatial distribution of monthly mean air temperatures in the Tibetan Plateau and its neighboring areas. Time series analysis and both ordinary linear regression (OLS) and geographical weighted regression (GWR) of monthly mean air temperature (Ta) with monthly mean land surface temperature (Ts) were conducted. Regression analysis shows that recorded Ta is rather closely related to Ts, and that the GWR estimation with MODIS Ts and altitude as independent variables, has a much better result with adjustedR2> 0.91 and RMSE = 1.13–1.53°C than OLS estimation. For more than 80% of the stations, the Ta thus retrieved from Ts has residuals lower than 2°C. Analysis of the spatio-temporal pattern of retrieved Ta data showed that the mean temperature in July (the warmest month) at altitudes of 4500 m can reach 10°C. This may help explain why the highest timberline in the Northern Hemisphere is on the Tibetan Plateau.