基于全极化雷达数据反演夏玉米覆盖农田表层土壤含水量

基于RADARSAT-2全极化C波段雷达数据和野外实测数据,建立了不同极化方式的后向散射系数与夏玉米植被含水量的响应关系,获得了山东禹城夏玉米覆盖区域农作物含水量。在此基础上,对＂水—云模型＂的参数进行了修改,从总的极化雷达后向散射中去除了植被影响,获取了土壤组分的后向散射系数,从而能够通过雷达多极化数据得到表层土壤含水量。结果表明：夏玉米植被含水量观测值与VH、VV后向散射系数的相关性均达到显著水平,相关系数分别为0.86和0.79,VH极化优于VV极化;在RADARSAT-2四种极化方式下,VV极化下的＂水—云模型＂理论计算的误差平方和最小,是研究区表层土壤含水量反演的最优极化方式。

Surface soil moisture of farmland covered by summer corn stalk retrieved by full polarimetric radar data

Based on the RADARSAT-2 full polarization C-band radar data and field survey data,the paper set up the response relationship between backscatter coefficient of different polarization modes and vegetation water content of summer corn,and got the water content of summer corn crop in covered area of Shandong Yucheng. On this basis,it modified the parameters of water-cloud model and obtained the backscatter coefficient of soil components from removing the backward scattering field of the total polarization radar vegetation influence so as to get surface soil water content by radar data of multipolarization. The results show that the correlation between vegetation water content of summer corn and VH,VV scattering coefficient reached significant level,correlation coefficient is 0. 86 and 0. 79 respectively,the value of VH polarization is better than that of VV polarization; Under the four polarization modes of RADARSAT-2 and the water and cloud model of VV polarization,error sum of squares of theory calculation is the least,which is the optimal polarization inversion type of surface soil water content in the study area.