The dynamic observation of dissolved organic matter in the Zhujiang(Pearl River)Estuary in China from space  

作　　者：LIU Dong BAI Yan HE Xianqiang PAN Delu WANG Difeng WEI Ji'an ZHANG Lin 

机构地区：[1]State Key Laboratory of Satellite Ocean Environment Dynamics,Second Institute of Oceanography,State Oceanic Administration,Hangzhou 310012,China [2]Key Laboratory of Watershed Geographic Sciences,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,China

出　　处：《Acta Oceanologica Sinica》2018年第7期105-117,共13页海洋学报（英文版）

基　　金：The National Key Research and Development Progam of China under contract No.2017YFA0603003;the National Basic Research Program(973 Program)of China under contract No.2015CB954002;the Public Science and Technology Research Funds Project of Ocean under contract No.201505003;the National Natural Science Foundation of China under contract Nos41676170,41676172,41476155,41621064 and 41406202;the Project of State Key Laboratory of Satellite Ocean Environment Dynamics,Second Institute of Oceanography,State Oceanic Administration of China under contract No.SOEDZZ1801;the Research Startup Project of Nanjing Instiute of Geography and Limnology,Chinese Academy of Sciences under contract No.Y7SL051001

摘　　要：The distributions of estuarine colored dissolved organic matter（CDOM）are the combined results of physicalbiogeochemical processes.Remote sensing is needed to monitor highly dynamically estuarine CDOM.Using in situ data from four seasonal cruises,an algorithm is developed to estimate CDOM absorption coefficient at 400nm（aCDOM（400））in the Zhujiang（Pearl River）Estuary（ZJE）.The algorithm uses band ratios of Rrs（667）/Rrs（443）and Rrs（748）/Rrs（412）.By applying it to moderate resolution imaging spectroradiometer onboard Aqua satellite（MODIS/Aqua）data from 2002 to 2014,seasonal climatology aCDOM（400）in the ZJE is calculated.CDOM distributions are majorly influenced by water discharge from the Zhujiang River and underwater topography.Along the section vertical to a water depth gradient,the seasonal aCDOM（400）exponentially decreased（y=aebx,b〈0）,but with great differences among seasons.Riverine fresh water is the primary source of CDOM in the ZJE.Fulvic acid fraction decreases with increasing salinity.Using developed algorithms,conservative CDOM mixing equation,and river discharge,effective riverine end-member concentration and flux of dissolved organic carbon（DOC）in summer and winter from 2002 to 2014 are first estimated from the MODIS/Aqua data.Both effective riverine end-member DOC concentration and flux are positively related to the river discharge,significantly in summer with R-2 of 0.698 for concentration and 0.965 7 for flux.The distributions of estuarine colored dissolved organic matter（CDOM）are the combined results of physicalbiogeochemical processes.Remote sensing is needed to monitor highly dynamically estuarine CDOM.Using in situ data from four seasonal cruises,an algorithm is developed to estimate CDOM absorption coefficient at 400nm（aCDOM（400））in the Zhujiang（Pearl River）Estuary（ZJE）.The algorithm uses band ratios of Rrs（667）/Rrs（443）and Rrs（748）/Rrs（412）.By applying it to moderate resolution imaging spectroradiometer onboard Aqua satellite（MODIS/Aqua）data from 2002 to 2014,seasonal climatology aCDOM（400）in the ZJE is calculated.CDOM distributions are majorly influenced by water discharge from the Zhujiang River and underwater topography.Along the section vertical to a water depth gradient,the seasonal aCDOM（400）exponentially decreased（y=aebx,b〈0）,but with great differences among seasons.Riverine fresh water is the primary source of CDOM in the ZJE.Fulvic acid fraction decreases with increasing salinity.Using developed algorithms,conservative CDOM mixing equation,and river discharge,effective riverine end-member concentration and flux of dissolved organic carbon（DOC）in summer and winter from 2002 to 2014 are first estimated from the MODIS/Aqua data.Both effective riverine end-member DOC concentration and flux are positively related to the river discharge,significantly in summer with R-2 of 0.698 for concentration and 0.965 7 for flux.

关 键 词：colored dissolved organic matter dissolved organic carbon Zhujiang（Pearl River）Estuary effective riverine end-member flux remote sensing 

分 类 号：X52[环境科学与工程—环境工程]