Air Temperature Estimation with MODIS Data over the Northern Tibetan Plateau
Author: 
Huang, F. F., W. Q. Ma, B. B. Wang, Z. Y. Hu, Y. M. Ma, G. H. Sun, Z. P. Xie and Y. Lin 
Abstract: 
Time series of MODIS land surface temperature (Ts) and normalized difference vegetation index (NDVI) products, combined with digital elevation model (DEM) and meteorological data from 2001 to 2012, were used to map the spatial distribution of monthly mean air temperature over the Northern Tibetan Plateau (NTP). A time series analysis and a regression analysis of monthly mean land surface temperature (Ts) and air temperature (Ta) were conducted using ordinary linear regression (OLR) and geographical weighted regression (GWR). The analyses showed that GWR, which considers MODIS Ts, NDVI and elevation as independent variables, yielded much better results [RAdj(2) > 0.79; rootmeansquare error (RMSE) = 0.51 degrees C1.12 degrees C] associated with estimating Ta compared to those from OLR (RAdj(2) = 0.400.78; RMSE = 1.60 degrees C4.38 degrees C). In addition, some characteristics of the spatial distribution of monthly Ta and the difference between the surface and air temperature (Td) are as follows. According to the analysis of the 0 degrees C and 10 degrees C isothermals, Ta values over the NTP at elevations of 40005000 m were greater than 10 degrees C in the summer (from May to October), and Ta values at an elevation of 3200 m dropped below 0 degrees C in the winter (from November to April). Ta exhibited an increasing trend from northwest to southeast. Except in the southeastern area of the NTP, Td values in other areas were all larger than 0 degrees C in the winter.

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Page number: 
650662 
Issue: 
5 
Subject: 

Authors units: 

PubYear: 
2017 
Volume: 
34 
Publication name: 
Advances in Atmospheric Sciences 
Abstract: 
Time series of MODIS land surface temperature (Ts) and normalized difference vegetation index (NDVI) products, combined with digital elevation model (DEM) and meteorological data from 2001 to 2012, were used to map the spatial distribution of monthly mean air temperature over the Northern Tibetan Plateau (NTP). A time series analysis and a regression analysis of monthly mean land surface temperature (Ts) and air temperature (Ta) were conducted using ordinary linear regression (OLR) and geographical weighted regression (GWR). The analyses showed that GWR, which considers MODIS Ts, NDVI and elevation as independent variables, yielded much better results [RAdj(2) > 0.79; rootmeansquare error (RMSE) = 0.51 degrees C1.12 degrees C] associated with estimating Ta compared to those from OLR (RAdj(2) = 0.400.78; RMSE = 1.60 degrees C4.38 degrees C). In addition, some characteristics of the spatial distribution of monthly Ta and the difference between the surface and air temperature (Td) are as follows. According to the analysis of the 0 degrees C and 10 degrees C isothermals, Ta values over the NTP at elevations of 40005000 m were greater than 10 degrees C in the summer (from May to October), and Ta values at an elevation of 3200 m dropped below 0 degrees C in the winter (from November to April). Ta exhibited an increasing trend from northwest to southeast. Except in the southeastern area of the NTP, Td values in other areas were all larger than 0 degrees C in the winter. 
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