Temporal And Spatial Variations Of Suspended Sediment And Chlorophyll-a In Laizhou Bay In Recent 20 Years Based On Remote Sensing Inversion

As the state attaches importance to the marine economy and the marine strategy,the development and utilization of the ocean are also being protected more and more intensively.In view of the problems of marine pollution and the development of marine resources,the monitoring techniques and means of researching the ocean are getting more and more accurate.Marine remote sensing technology is a powerful tool for monitoring seawater quality and the marine environment.Based on the current status of the research on water color remote sensing both at home and abroad,the inversion of suspended sediment and chlorophyll a in different periods and under different dynamic conditions in Laizhou Bay from 1996 to 2015 was studied by using the multi-spectral data of landsat series.Spatial and Temporal Distribution Characteristics and Diffusion Rules of Suspended Sediment and Chlorophyll a in the Bay Sea Area.The specific research work in this paper is mainly the following aspects:(1)Elucidating the research mechanism of water color remote sensing,the progress of research on water color remote sensing at home and abroad is systematically introduced,especially the quantitative inversion of suspended sediment and chlorophyll a in nearshore bodies and their application status and progress.It has a clear reference and guidance to the research area of Laizhou Bay,and selects suitable landsat series of products for multi-spectral remote sensing data of water quality remote sensing inversion.(2)Introduced the regional background and basic conditions of Laizhou Bay area in detail,introduced the satellite remote sensing data briefly,introduced the multispectral remote sensing data processing flow,and established the water thematic information extraction and water quality specific information extraction new method.(3)The 16 remote sensing images of Laizhou Bay from 1996 to 2015 were selected to conduct a series of preprocessing of remote sensing images to improve the quality of image information.Based on the analysis of the physical optical properties of suspended sediment and chlorophyll a,an inversion model of suspended sediment and chlorophyll a concentration in the Laizhou Bay based on spectral information was established and the ideal inversion result was obtained.Using only the spectralinformation extracted from remote sensing images to establish the water color inversion model,the suspended sediment and chlorophyll can be reconstructed on the surface of large scale watershed,which can quickly identify the change of water color and make the remote sensing more convenient and simple for aqua analysis.(4)The spatial and temporal distribution and diffusion of suspended sediment in Laizhou Bay are analyzed in detail.The distribution range of suspended sediment in the Laizhou Bay waters is affected by the runoff into the sea in the dry season.The distribution range of the dry season is larger than that of the wet season.The high velocity belts outside the Yellow River estuary and the tidal shear front jointly control the spreading direction and range of the suspended sediment The high concentrations of suspended sediment in Laizhou Bay are mainly distributed in the waters near the mouth of the Yellow River and Xiaoqing River.Generally,winds affect the spread of suspended sediment on the surface of Laizhou Bay under the condition of wind below 5 levels.However,the general characteristics of the suspended sediment diffusion and distribution have not changed,and the trend is still the main driving force for the diffusion of suspended sediment.Laizhou Bay High The flow velocity zone and the high concentration of suspended sediment in the surface accompany with each other.(5)Spatial and temporal distribution and diffusion of chlorophyll a in Laizhou Bay were analyzed in detail.The chlorophyll a high concentration water in Laizhou Bay waters mainly distributes in the east coast and southeast of Laizhou Bay and distributes in the shape of flake.It disperses from the nearshore to the bay under the tidal current and other dynamic forces.Chlorophyll a content varied in different seasons in different areas of Laizhou Bay.Chlorophyll a coverage in wet season was greater than that in dry season,and chlorophyll a content in dry season was significantly higher than that in wet season.The distribution of chlorophyll a also showed obvious seasonal distribution with the lowest concentration in winter.With the temperature rising in spring,the phytoplankton grew rapidly in summer and peaked in summer.The concentration of chlorophyll a in water was the highest.With the decreasing of water temperature in autumn,the nutrients in water also consumed To do,chlorophyll a concentration gradually decreased.Large-scale reservoirs and soil and water conservation projects,as well as coastal marine aquaculture,have a certain impact onchlorophyll-a concentration in coastal waters.