土壤中红外发射率提取算法研究

基于四步观测法,提出了一种土壤中红外发射率提取方法.该方法利用热红外的ISSTES算法获得土壤热红外的发射率光谱和高精度的土壤温度估值,并将得到的温度估值用于中红外的发射率提取,减少中红外待反演参数.形成多余观测,使用最小二乘方法求解土壤中红外的发射率.重点分析了仪器定标误差和辐射传输方程简化对中红外发射率提取的影响.最后,基于模拟数据给出了中红外部分波段发射率反演误差较大的原因.

ALGORITHM STUDY ON SOIL MID-INFRARED EMISSIVITY EXTRACTION

Based on the four step method, a method for deriving soil mid-infrared emissivity was put forward. The first step, soil temperature was inversed by the ISSTES algorithm from thermal infrared data; The second step, the soil temperature was introduced to make the inversion equation complete in mid-infrared domain ; The third step, the least square meth- od was applied to solve the formulations and then the mid-infrared emissivity was obtained. More attention was paid to analyze the impacts of instrument calibration error and simplification of radiative transfer equation on the extraction of soil emissivity in mid-infrared. Finally, the reason for large error of emissivity inversion in some bands of mid-infrared was pointed out based on the simulated data.