基于多时相主被动遥感的漓江水面监测与水质参数反演(2016-2020年)

以漓江流域为研究区域,以2016-2020年Landsat 8 OLI、GF-1、Sentinel-2A及Sentinel-1A逐月影像为数据源,选用归一化水指数(NDWI)、改进型归一化水指数(MNDWI)、增强型水体指数(EWI)、归一化差值池指数(NDPI)、后向散射系数(S)与主被动遥感加权指数(JQ)提取漓江...

Water surface monitoring and water quality parameters inversion of Lijiang River based on multi-temporal active and passive remote sensing, 2016-2020

Lijiang River Basin is used as the research area,and Landsat 8 OLI,GF-1,Sentinel-2A,and Sentinel-1 A monthly images of 2016-2020 are used as data sources.The normalized water index(NDWI),modified normalized water index(MNDWI),enhanced water index(EWI),normalized difference pond index(NDPI),backscatter coefficient(S)and weighted index of active and passive remote sensing(JQ)are used to extract the water information of the Lijiang River.The case 2 regional coast color(C2 RCC),maximum chlorophyll index(MCI),two band ratio method(Double R)and chlorophyll reflection peak intensity(ρchl)are used to retrieve the concentration of chlorophyll-a(Chl.a)and total suspended matter(TSM)concentrations in Lijiang River.The Lijiang River is divided into 278 basic evaluation units,and the spatial-temporal dynamic changes of hydrological and water quality information in the upper,middle,and lower reaches in dry and flood seasons of Lijiang River are quantitatively analyzed by difference value of water surface variation(WDr),shoreline development index(SDI)and dynamic degree of water information change(K).The following conclusions are drawn:(1)Compared with NDWI,MNDWI,EWI,and backscatter coefficient,the extraction effect of JQ and NDPI are better.Compared with JQ,NDPI has higher precision and credibility.(2)RMSE of Chl.a based on the inversion of C2RCC algorithm is 0.18-7.88 mg/m³,RMSE of TSM is 0.17-12.55 g/m³,and it can better reflect the changing trend of Chl.a.(3)The division of the basic evaluation unit can clearly analyze the continuous changes of the width,area,Chl.a and TSM of the upstream,middle and downstream areas.The measured data rely on the monitoring of the stations,and the results are scattered and can’t be used for continuity analysis.(4)The Lijiang River has more precipitation and strong water mobility from May to October.The average water surface width of most areas is within 100-250 m.However,the water nutrient is low and the water quality is good.The water quality is the worst in February.The areas with high eutrophication are mainly concentrated in Xing’an County,Lingchuan County and other urban residential areas in the upper and middle reaches,and Xingping town with more tourism development zones downstream.