Atm,ospheric Aersol Model And Seawater Backcattering Model For Regions Fo Est China Seas

East China Seas are famous for containing turbid coastal waters and are typical case II waters. East China Seas are abundant of phytoplankton, suspended particulate matter and colored dissolved organic matter due to the Yellow River and Yangtze River plumes and a coastal industrial city layout. The atmospheric aerosols have strong absorption properties resulting from the invasion of sand and land-based sources of soot transporting from Mongolia and Desert regions in northern China atmospheric. Therefore, the ocean color data products provided with overseas sensors, e.g., MERIS, MODIS, have big errors for coastal waters in East China Seas. The Chinese in-orbit ocean color sensors, i.e., FY-3A/MERSI and HY-1b/COCTS are actually lack of reliable data products.This paper is focused on Envisat/ MERIS data, which is relatively best in-orbit ocean color sensor at present. Using data sets of ocean and atmospheric field measurements during 1998-2010 in East China Seas and atmosphere - ocean radiative transfer modeling, further study on aerosol model and seawater backscattering model for East China Seas were made. The models are the key to solve the ocean color retrieval algorithm for East China Seas. The main results are listed as follows:1.Evaluation of atmospheric correction algorithm for MERIS and MODIS in East China Seas.The evaluation results suggest that the average validation error of Rrs( ) from ESA atmospheric correction algorithm in East China Seas can reach 71% and the maximum of the validation error is as high as 300%. The distributions of single scattering albedo SSA-?ngstr?m exponent were used to examine the characteristics of aerosol models, aerosol size distribution and index of refraction. The ESA and NASA aerosol models cannot represent the aerosol characteristics over East China Seas. The performance of ESA atmospheric correction algorithm in East China Seas is generally better than the NASA SeaDAS 6.1 atmospheric correction algorithm.2.Optical properties of aerosols over East China SeasAccording to the range of aerosol optical depth a and ?ngstr?m exponent for various types of aerosols, the category distribution of a– over East China Seas, and the size distribution and single scattering albedo for three aerosol types were first provided by use of data from 19 ground-based stations in East China Seas of AERONET and SKYNET aerosol-monitoring network and 620 stations in 6 cruises of Ocean Remote Sensing Institute Ocean Optics DataBase ORSIO2DB, Ocean University of China. The aerosols over East China Seas are dominated by the mixture of sea salt (CM), soot (BU) and sand (DD). The effect of soot is greater than sand, and the effect of sand is associated with areas and seasons. Little areas and seasons are dominated by sea salt aerosols. Based on the statistics of field data, the statistical parameters for aerosol optical properties over East China Seas were given.3.Aerosol models over East China Seas and aerosol reflectance look-up table.According to the field measurements of aerosol size distribution and index of refraction, as well as bimodal lognormal particles size distribution, aerosol models over East China Seas were provided for the first time, including the tables of aerosol size distribution and index of refraction. Based on the established aerosol models, the aerosol optical properties computed with Mie theory were compared with field measurements. They agreed well. Another group of field measurements were used for validation. The aerosol reflectance look-up table over East China Seas was established using atmosphere-ocean radiative transfer modeling MOMO developed by Free University Berlin, Germany.4.Seawater backscattering models for East China SeasThe scattering coefficient spectral model for suspended particulate matter bp( )published in Doxaran et al. (2009) was selected as a reference. The expression and average value of parameter for East China Seas were obtained by fit. The relative errors between the computed value of bp( ) from the model and the in-situ value are 4.76% and 5.22%, and the RMSE are 0.1117 and 0.1199. Based on Morel’s backscattering coefficient spectral model for suspended particulate matter bbp( ), the expression and average value of the power exponent in the bbp( ) model were derived by fit. The relative errors between the modeled and in-situ values of bbp( ) are 5.22% and 5.24% , and the RMSE is both 0.0016 . On this basis, the spectral model of bbp( )/ bp( ) for East China Seas was established. Using simultaneous measurements of concentration of suspended particulate matter SPM, the empirical relationship between SPM and bp(532), bbp(532), bbp(532) / bp(532) were further established respectively.