塔克拉玛干沙漠地表发射率及分布变化特征

Charactistics of Land Surface Emissivity on Distribution and Variation in Taklimakan Desert

利用便携式傅立叶变换热红外光谱仪,对冷热黑体辐射和漫反射金板辐射校正,测量波长在8-14μm的热红外大气窗口的地表辐射光谱,计算出地表发射率光谱,再转换成地表的发射率值（ε）。2013年10月16-18日,沿着沙漠公路,从南至北穿越塔克拉玛干沙漠,平均每50 km选择一个观测点进行测量,采集到10个观测点的地表发射率光谱数据,计算出每个观测点的精确ε,获得了塔克拉玛干沙漠地表发射率的分布变化特征。结果表明：靠近绿洲的地表发射率值最高,达到0.93,绿洲与沙漠过渡带的值为0.91-0.92,沙漠其它地区的值为0.90-0.91,而沙漠腹地区域的值小于0.90。

Estimating accurate land surface emissivity （e） from data collected by fieldmeasurements using a portable Fourier transform infrared spectrometer was investigated. Aftercalibrated radiances of blackbody in cold and warm conditions as well as a gold diffuse plate, thespectra of surface broadband radiance was measured in 8-14 μm thermal infrared atmosphericwindow. Hence, the spectra of surface broadband emissivity can be derived from the surfacebroadband radiance for determining emissivity. The data were collected along a highway from southto north, which cross Taklimakan desert, at every -50 km on October 16th to 18th, 2013. Then thecharacteristics of distribution and variation of land surface emissivity were obtained. It shows thatthe regions near oasis have high emissivity of 0.93, and values in the regions of transitional zonebetween oasis and desert range from 0.91 to 0.92. The values in the other regions vary from 0.90 to0.91, and the central regions of the desert have the lowest emissivity, less than 0.90.