Research On The Absorption Characteristics And Remote Sensing Inversion Of Chromophoric Dissolved Organic Matter In Poyang Lake

Poyang Lake is China's largest freshwater lake and a highly dynamic throughput type lakes,it has many functions as regulating runoff,irrigation development,provision of industrial and drinking water,breeding of aquatic organisms,communication and shipping and so on.However,in recent years,with the rapid economic development of Poyang Lake Basin,soil erosion leads to hydrological environment changes and the security risks of lake and wetland ecosystems,thus the ecological protection and the effective monitoring of Poyang Lake water body composition changes can not be urgently.Colored dissolved organic matter?CDOM?is an important component of the water body,it is the great significance for the study of Poyang Lake water monitoring changes in body composition and color remote sensing to understand CDOM concentration distribution of inland lakes,the optical properties and composition changes.According to the three measured dates of CDOM concentration and water body spectral data,analyzing the optical properties,distribution and sources of CDOM waters of Poyang Lake.Basing on measured data to build a yellow substance inversion model of Poyang Lake,researching remote sensing of yellow substance concentration of Poyang Lake waters in nearly two years.Poyang Lake CDOM concentration?Yellow substance absorption coefficient ag?440?represented at a wavelength of 440nm?ranges of three measurements were 0.254-0.800 m^-1 in July 2014,0.359-0.613 m^-1 in September 2014,0.405-0.738 m^-1 in August 2015.in the around waters of the river channel,CDOM concentration change is more obvious due to effects of terrestrial inputs and organic matter from the bottom of the floating.the average of the third measured CDOM concentration are higher than other two measurements with an average of 0.581 m^-1,most of the concentration of high value areas are concentrated in the coastal waters.CDOM concentration profile decreases from the coast to the main lake,CDOM concentration in main lake area generally low.Sg change shows the different components of the yellow substance,the measured Sg change in 2015 is between 0.014-0.018,the yellow material composition of this part waters is more stable.In this paper,the results show its relevance low for analyzing ag?440?and Sg and sediment.The article discusses the advantages and disadvantages of existing CDOM inversion model,the suitability of the model was evaluated for the inverse model to Poyang Lake waters;Through the study of the measured data and yellow substance inversion model,try to build the Poyang yellow substance inversion model,the results show the ratio of two-band inversion model higher correlation than the average single-band and band inversion model with related coefficient of 0.7598,inversion accuracy of yellow substance concentration of Poyang Lake is about 20%.Finally,in accordance with pretreatment HJ-CCD satellite images of the past two years inverses CDOM concentration of Poyang Lake for studying the dynamic changes of its concentration.