Research On Remote Sensing Monitoring Of Impervious Surface In Fuxian Lake Basin And Its Water Environment Response

Accelerating process of urbanization has prompted a rapid increase in impervious surface.Impervious surface is an indicator to characterize the degree of urbanization which exerts an important impact on urban ecological environment change.Development of remote sensing technology makes it possible to quickly and accurately extract impervious surface.With the constant deepening of impervious surface research,the impact on water environment with impervious surface changes are generally concerned.The study takes the rapid urbanization zone of Fuxian lake basin,Yunnan as a case,and it uses Landsat ETM+images as data source.Combined with Wu&Murry four terminal element model and linear spectral mixture model after Gram-Schmidt?GS?image fusion,we extracted the condition of the impervious surface distribution.We picked up 2006,2009,2012,2015 four image data between 2006 and 2015.After verification,Combined with Wu&Murry four terminal element model and linear spectral mixture model can extract the information of the impervious surface distribution better.We can base on the result of linear spectral mixture model.Quantitative analysis of spatial and temporal variations of impervious surface process by several kinds of aspects,such as impervious surface cover,impervious surface in 8 sub-watersheds and impervious surface expansion.This study was conducted to verify the correlation between impervious surface and water quality to find out a threshold between impervious surface and water quality.The water environment response of impervious surface changes was analyzed from qualitative and quantitative methods.Those results can provide useful suggestions for urban development,environment management and land use.The main findings from this paper are as follows.?1?Achieve the extraction of impervious surface of Fuxian lake basin based on LSMM.The spatial distribution of impervious surface from 2006²015 was obtained by linear spectral mixture model?LSMM?combined with Wu&Murry four terminal element model and the Landsat ETM+images in 2006,2009,2012,2015.After verification,images estimated by LSMM from 2006 to 2015 meet the requirement,the average value of RMS is less than 0.02,it is feasible that this paper use linear spectral mixture model to extract information of impervious Surface of Fuxian lake basin.?2?Identify the features of impervious surface change of Fuxian lake basin in the urbanization process.The impervious surface area and percentage of impervious surface for the study area appeared to increase from 2006 to 2015.Impervious surface cover of Fuxian lake basin have a change in recent 10 years,Natural surface?NOISA?is decreased by 2.97%,which is about 20.05 square kilometers.Full density impervious surface area?FDISA?is increased by 0.53%,which is about 3.59 square kilometers.The total intensity of expansion is 4.68 in the Fuxian lake basin,The maximum intensity of expansion from 2009 to 2012 is 7.16.?3?Analysis the spatial and temporal variation characteristics of the water quality in the Fuxian lake basin.The concentrations of COD_Mn,TP,TN and COD in the two sub-watersheds with high urbanization level were high among the 8sub-watersheds.As for the 8 sub-watersheds,the concentrations of COD_Mn?TP and COD were higher in the dry season than that in the average season and the wet season.?4?Explore the response between the percentage of impervious surface and water quality in Fuxian lake basin.There were significantly positive correlations between the percentage of impervious surface and COD_Mn?TP?r=0.772,0.763?.It illustrates the percentage of impervious surface in sub-watersheds have a strong influence on water quality.The correlation between COD_Mn?TP and the percentage of impervious surface is greater in the wet season than that in the dry season.The cluster analysis between the percentage of impervious surface and water quality indicators in8 sub-watersheds in 2015 shows that 10%is supposed to be the threshold of impervious surface in Fuxian lake basin.