Remote Sensing Inversion Of Diffuse Attenuation Coefficient And Transparency In Poyang Lake

The diffuse attenuation coefficient and transparency are the key parameters to describe the optical properties of the water,which can directly reflect the light field distribution and light intensity of the water.When the water body attenuation coefficient and transparency change,it may seriously affect the growth of underwater vegetation and aquatic animals,and change the type of water ecosystem.Remote sensing research on diffuse attenuation coefficient and transparency can not only provide important data for large-scale water ecological environment monitoring,but also provide important theoretical support and practical value for exploring the optical principles of the second-class water body and perfecting the mechanism of water color remote sensing.This article takes Poyang Lake as the research object and uses the field data of field water measured in August 2015to analyze the optical properties of the water in Poyang Lake.At the same time,it analyzes the influence of various components of the water on the 490 nm wave attenuation coefficient Kd(490),and then simulates HJ.The remote sensing inversion model of Poyang Lake's water attenuation coefficient was constructed by using image bands,and it was parameterized by the method of approximate equal spacing.Secondly,the water transparency of Poyang Lake was constructed based on the relationship between transparency,remote sensing reflectivity and Kd(490),and empirical algorithm.Inversion model;Finally,the Kd(490)and transparency inversion models were applied to HJ images to analyze the characteristics of spatio-temporal changes.The results show that suspended sediment is the main component that influences the attenuation coefficient of Poyang Lake water,its impact value is higher than other water components,followed by chlorophyll a concentration,and yellow matter has the smallest impact on diffuse attenuation coefficient.Based on the combination of green wave,red wave and near-infrared bands,a Kd(490)inversion model is established.The inversion results are good.The average relative error is 42.1%,the root mean square error is 2.944,and the determination coefficient R~2 is 0.722;Kd is established.490)Parametric model,the result is good.Transparency and Kd(490)are negatively correlated;a transparency inversion model is established based on the quadratic function equation of the ratio of the red and green bands,the inversion result is good,the root mean square error is 0.08,the average relative error is 20.9%,and the coefficient of determination 0.813.The attenuation coefficient and transparency of Poyang Lake's water body have a certain degree of spatio-temporal differences.During the wet season,Kd(490)gradually increases from the lake mouth to the upstream direction through the river entrance channel,and the transparency decreases,and the nearer it is to the lake.The transparency of the edge is greater;the eastern part of the east and southwest of the area change significantly;in the dry season,the spatial distribution of Kd(490)is not obvious,and the value of Kd(490)changes only at the confluence of the near bank and the tributary,and the transparency is in the east and northeast.The Department is relatively large and other areas are relatively small.