Simultaneous Retrieval Of Aerosol Optical Depth And BRDF Over Coastal/inland Waters Based On Multi-angle Sensor

The coastal/inland water accounts for a small proportion of the earth surface,but it is the important area for human life.The ecological can exert a huge impact on the economy and climate.However,as the transfer radiative process is complex due to the differences of optical properties and regions,there are many restrictions in quantitative remote sensing.To solve this problem,this study proposes a simultaneous retrieval of Aerosol Optical Depth(AOD)and Bidirectional Reflectance Distribution Function(BRDF)over coastal/inland waters based on multi-angle sensor,and applies the algorithm in some example areas.The retrieval results has been validated in coastal waters and inland lakes.This study provides support for quantitative remote sensing over coastal/inland waters.The main achievements are as follows:(1)The researches on the bidirectional reflection distribution function over water are introduced in this manuscript.This study compare four common BRDF models developed over coastal waters.As there are few studies on inland waters,the applicability of these models is analyzed in inland lakes.With the DATA from the multi-angle sensor MISR and the records from the ground-based station AERONET,the models is conducted in Lake Erie(a typical clear lake)and Taihu(a typical turbid lake).The results prove that Lee2011 model performs well in various conditions of waters.The comparison and analysis provide a theoretical basis in selecting a proper BRDF model for the simultaneous retrieval.(2)The simultaneous algorithm for retrieval of aerosol optical depth and bidirectional reflectance distribution function over coastal/inland waters is developed based on the radiative transfer equation and the hypothesis that the BRDF parameters are invariant with wavelength.The sensitivity study is based on the aerosol optical characteristics and BRDF model.The results prove that the aerosol models are important for the accuracy of retrieval.In addition,the algorithm is proved to be robust by introducing errors to the input of the algorithm.(3)The proposed algorithm is applied to several coastal/inland waters,including the Ariake Sea(typical turbid coastal waters in a semi-closed bay of Japan),Lucinda Bay(clear open coastal waters in Australia),Lake Erie(typical clear inland waters,one of the Great Lakes)and Taihu(typical turbid lake in he Yangtze River Delta of China).The results are validated with the products of AERONET and AERONET-OC stations.The comparison with MODIS and MISR products shows a advantage of our retrieval results in resolution and coverage.These case analysis prove that the proposed algorithm is applicable for various coastal/inland waters.As the attention in coastal/inland waters area is increasing in both atmospheric and water color remote sensing and the multi-angle remote sensors play a more and more important role in the researches,the simultaneous retrieval of aerosol optical depth and bidirectional reflectance distribution function based on multi-angle sensor provides a new idea for the quantitative remote sensing in the coupled water-atmospheric system in coastal/inland waters.