地表粗糙度的测量计算方法及其对微波辐射散射的影响分析

Measurement and Calculation Method of Surface Roughness and Its Impact on Microwave Radiation Scattering

地表粗糙度反映了地表的微小起伏,是土壤水分微波遥感反演研究中重要的地表参数。以闪电河流域为研究区,首先利用针板法对不同地物下的地表粗糙度进行测量,然后对测量数据进行透视变换、数字化、倾斜校正及周期校正等一系列的处理,计算得到不同地表的粗糙度结果。研究表明:在使用针板法测量地表粗糙度时,为校正不同剖面测量姿态的影响需要进行倾斜校正以减小计算偏差,而对胡萝卜地、花菜地等具有周期性田垄结构的地表还需要进一步进行周期校正。通过对获取的闪电河流域典型地物的地表粗糙度进行分析,发现该地区草地的地表粗糙度较小,作物区的地表粗糙度普遍偏大,各类地物的地表粗糙度由小到大分别为草地、花菜地、玉米地、胡萝卜地、土豆(收割)地和土豆(未收)地。最后对地表粗糙度与机载微波辐射、散射观测进行相关性分析,发现在地面单点测量的地表粗糙度与机载尺度的微波辐射散射特性之间不存在明显关系。

The surface roughness reflects the small fluctuations of the surface and is an important surface parameter in the microwave remote sensing inversion of soil moisture. In this paper,the Lightning River Basin is used as the research area. First,the surface roughness of different ground objects is measured using the pin-plate method,and then a series of processing such as perspective transformation,digitization,tilt correction and period correction are performed on the measured data. Surface roughness results. Studies have shown that when measuring the surface roughness using the pin plate method,in order to correct the influence of the measurement attitude of different sections,tilt correction is required to reduce the calculation bias,and the ground surface with periodic ridge and ridge structure such as carrot field and cauliflower field needs further Perform period correction. By analyzing the surface roughness of typical objects in the Lightning River Basin,it is found that the surface roughness of the grassland in this area is small,the surface roughness of the crop area is generally large,and the surface roughness of various types of objects is from small to large They are grassland,cauliflower field,corn field,carrot field,potato(harvest)field,and potato(unreceived)field. Finally,the correlation analysis between the surface roughness and the airborne microwave radiation and scattering observations was conducted,and it was found that there was no obvious relationship between the surface roughness measured at the ground single point and the airborne scale microwave radiation scattering characteristics.