针对TM6有效波长的计算方法及其对地温反演的影响研究

A Research on the Algorithm of Equivalent Wavelength and the Impact to the Retrieved LSBT Based on TM6

相对NOAA-AVHRR及MODIS的热波段而言,Landsat TM6有更高的空间分辨率;因而更适合于地面热力场分布特征及微环境研究的准确分析需要。有效波长的确定对反演地表温度有重要影响。本文根据Landsat5及Landsat7 TM6对波长的光谱响应函数(RSR),推导出相应的有效波长值并分析其对地温反演的影响。分析结果表明,一般情况下,就Landsat5而言,用中心波长反演地表温度不会有太大影响;但利用Landsat7反演地表温度时则必须使用有效波长,因为中心波长可能会导致较大的地表温度反演误差。

Landsat TM6 data have much higher spatial resolution than NOAA-AVHRR＇s and MODIS＇ thermal band data. Thus it is more suitable to use TM6 data for land surface temperature （LST） retrieval when precise spatial pattern of thermodynamic field is needed. Wavelength is an important parameter for LST retrieval from TM6 data. In this paper, the concept of effective wavelength is proposed for LST retrieval on the basis of Planek theory and TM6＇s relative spectral response （RSR） function for Landsat5 and Landsat7. It can be concluded that there is no significant difference on LST retrieval for Landsat5when central wavelength or effective wavelength is used. However, for Landsat7 it is better to use effective wavelength for LST retrieval because central wavelength may cause notable error in LST retrieval.