OuYang Xiaoying, Wang Ning, Wu Hua, Li Zhao-Liang
State Key Lab. of Resources and Environmental Information System, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.
Opt Express. 2010 Jan 18;18(2):544-50. doi: 10.1364/OE.18.000544.
Sensitivity analysis of temperature-emissivity separation method commonly applied to hyperspectral data to various sources of errors is performed in this paper. In terms of resulting errors in the process of retrieving surface temperature, results show that: (1) Satisfactory results can be obtained for heterogeneous land surfaces and retrieval error of surface temperature is small enough to be neglected for all atmospheric conditions. (2) Separation of atmospheric downwelling radiance from at-ground radiance is not very sensitive to the uncertainty of column water vapor (WV) in the atmosphere. The errors in land surface temperature retrievals from at-ground radiance with the DRRI method due to the uncertainty in atmospheric downwelling radiance vary from -0.2 to 0.6K if the uncertainty of WV is within 50% of the actual WV; (3) Impact of the errors generated by the poor atmospheric corrections is significant, implying that a well-done atmospheric correction is indeed required to obtain accurate at-ground radiance from at-satellite radiance for successful separation of land-surface temperature and emissivity.
本文对常用于高光谱数据的温度发射率分离方法针对各种误差源进行了敏感性分析。就地表温度反演过程中产生的误差而言，结果表明：(1) 对于非均匀陆地表面可获得满意结果，且在所有大气条件下，地表温度的反演误差小到可忽略不计。(2) 从地面辐射中分离大气下行辐射对大气中柱状水汽 (WV) 的不确定性不太敏感。如果WV的不确定性在实际WV的50%以内，使用DRRI方法从地面辐射反演陆地表面温度时，由于大气下行辐射的不确定性导致的误差在-0.2至0.6K之间；(3) 大气校正不佳所产生的误差影响显著，这意味着确实需要进行良好的大气校正，以便从卫星辐射中获得准确的地面辐射，从而成功分离陆地表面温度和发射率。
