基于被动微波遥感技术的玉米冠层叶面积指数反演

Crop LAI inversion based on the passive microwave remote sensing technology

基于玉米冠层结构参数实测数据和Matrix-Doubling(MD)模型构建了玉米出苗期至抽穗期的冠层多波段、双极化微波辐射特性模拟数据库;通过对模拟数据的回归分析得到了玉米冠层在各波段的微波发射率及其与透过率之间的经验关系,并将经验关系应用于0阶微波辐射传输模型;结合土壤发射率模型构建了玉米冠层覆盖地表的微波辐射亮温参数化计算模型,并基于该参数化模型、利用玉米样地微波亮温观测试验数据,采用迭代方法进行了玉米叶面积指数(LAI)的反演。研究表明,LAI反演值与实测值的相关系数r>0.9,说明多波段被动微波遥感数据在植被冠层LAI反演方面具有较大的应用潜力。

The multichannel dual-polarized radiation characteristic database of corn vegetation canopy was constructed by using the corn structure parameters field measured data and the Matrix-Doubling model,and the relations between the emissivity and the transmissivity of the corn canopy were obtained using regression analysis based on the database.These relationships were applied to the microwave radiation propagation equation to compute the microwave radiation bright temperature of the surface covered with corn canopy.The results show that the correlation of the measured LAI value and the model inversion LAI is higher than 0.9,which suggests that the multichannel passive microwave data have considerable application potential in the aspect of corn LAI inversion.