Remote Sensing Inversion Of Sea Surface Chlorophyll Concentration Based On HY-1C Data

In recent decades,under the dual influence of global climate change and human activities,water quality pollution in coastal areas has become increasingly serious and water eutrophication has intensified,leading to frequent Marine environmental disasters with increasing scale year by year and affecting the ecological service function of the Marine system.Therefore,long-term and accurate monitoring of Marine water quality is of great significance to the assessment of its ecological environment and the development and utilization of marine resources.Sea surface chlorophyll concentration is an important parameter of Marine plankton distribution and a basic index of Marine net primary productivity and eutrophication.Traditional sea surface chlorophyll concentration is usually carried out by field investigation and laboratory analysis.Although the accuracy is high,it is time-consuming and laborious,and it is often difficult to carry out large area investigation.Remote sensing technology,with its advantages of fast imaging speed,multiple spectral segments,wide imaging range,long time series and low economic cost,has rapidly become an important means of acquiring surface space resources and ecological environment information.With the progress of sensor technology,domestic ocean satellites with increasing quality and independent intellectual property rights provide an important platform for China’s ocean information acquisition.Therefore,based on the domestic ocean satellite data,this paper seeks for a suitable retrieval algorithm for chlorophyll concentration in the coastal waters of China.The main work is as follows:(1)Sensitivity analysis of sea surface chlorophyll concentration inversion band.The measured spectral data were used to calculate the water remote sensing reflectance,and combined with the measured sea surface chlorophyll concentration,the characteristics of water spectral curve with different sea surface chlorophyll concentration were analyzed.Considering single band,different band combinations and correlation indices(NDWI,NDVI and EVI),the band sensitivity analysis of measured sea surface chlorophyll concentration was carried out.The results showed that the band combinations of B3/B2and B3/(B2+B1)had the greatest correlation with chlorophyll concentration in the sea surface(0.77).(2)Remote sensing inversion model of chlorophyll concentration in sea surface for Domestic ocean satellite HY-1C.Based on the relationship between the remote sensing reflectance calculated from the measured spectral data and the measured sea surface chlorophyll concentration,a remote sensing inversion model of sea surface chlorophyll concentration was established by considering linear,polynomial,exponential and logarithmic mathematical forms.The experimental results show that the quadratic polynomial model(y=105.42x~2-175.67x+75.167)based on B3/B2 is the best,with a determination coefficient of 0.9107 and an average relative error of 26.85%.(3)Remote sensing inversion tool for chlorophyll concentration of sea surface based on IDL language.The remote sensing inversion module of HY-1C sea surface chlorophyll concentration was written by IDL language,which extended the function of ENVI.The results show that hy-1C remote sensing plug-in for retrieving sea surface chlorophyll concentration can operate stably and efficiently.Based on domestic ocean satellite data,this study constructed a remote sensing inversion model of sea surface chlorophyll concentration based on Hy-1C,developed a set of remote sensing inversion solution for sea surface chlorophyll concentration suitable for China’s offshore waters,and further improved the operational level of sea surface chlorophyll concentration inversion by domestic satellite.It is of great significance to the popularization of domestic satellite remote sensing data and the water quality monitoring in coastal waters.