Retrieval of Clear-sky Land Surface BRDF and Albedo Based on Discrepancy Principle and Regularization Method

A fast and robust novel algorithm is presented to retrieve land surface albedo over clear-sky areas,which is called hybrid algorithm.In this method,the initial guess value of regularization parameter was obtained by using the two parameter model function and then defined by a high order convergence algorithm.And the inversion of the kernel-driven BRDF model was implemented by Tikhonov regularization techniques.Measured data of surface targets with different cover types were chosen from POLDER-3/PARASOL BRDF datasets and then retrieved by the proposed algorithm.Comparison of results via the proposed method with that by MODIS full inversion was analyzed and discussed.At last,the retrieval experiments with MODIS satellite images over the regions of Tianjin were carried out,both error analysis and the evaluation of selected model and algorithm based on the retrieval results were also presented.