干旱区生态环境知识资源中心

Using spectral of broadband emissivity which was measured by Fourier Transform Infrared spectrometer (FTIR) over Taklimakan Desert and MODIS data, we developed an empirical regression equation to estimate the surface broadband emissivity for the spectral domains 8-13.5 mu m by the MODIS data. The accuracy of the equation was verified by the observed FTIR data and the MODIS spectral library data, respectively. Root mean square errors (RMSE) of the equation were 0.0041 and 0.0081, respectively. Then, the superiority and defect of observed FTIR data and MODIS spectral library were analyzed by each other, we found the FTIR data is better than spectral library data. At last, we selected the optimal regression equation to estimate the surface broadband emissivity of Xinjiang, and characteristics of spatial distribution for the broadband emissivity over four deserts in Xinjiang were analyzed. The results illustrated that the emissivity over Taklimakan Desert and Culukekum Desert are highly homogenous due to their stable climate and arid condition, which range is 0.850-0.915. Gurbantonggut Desert is influenced by vegetation and soil humidity, which emissivity is not well-distributed, their range is 0.890-0.915. However, the distribution of emissivity over Kumtagh Desert is similar to its plume underlying surface, which range is 0.860-0.910.