Spatio-temporal Change And Driving Force Analysis Of The Coastal Zone In Waters Between Xiamen And Kinmen Basecd On RS And GIS

Coastal zone is a strip district located in the transition area between sea and land.With the implementation of reform and opening-up,relying on its geographical spatial location and high productivity,and the policy of developing export-oriented economy by government of China,coastal zone become the region where economy develope rapidly,resource exploite and utilize most frequently and have the most densely populated.Waters between Xiamen and Kinmen located in the midddle of the Taiwan straits west coast,and center of Minnan golden triangle,is under Xiamen,Quanzhou and Kinmen administration.With the process of accelerative industrialization and urbanization,various of Marine engineering construction expande unceasingly,such as enclosing sea and cultivating,coastal reclamation and so on,consuming a large amount of natural coastline and tidal flat wetland,affecting the ecological environment of waters between Xiamen and Kinmen.But for Kinmen,which is under different society system with Xiamen and Quanzhou,the degree of coastal development is relatively low.Therefore,considering the kind of special geographic environment and economic status,in this study,the dynamic change of coastal zone in waters between Xiamen and Kinmen was monitored.In this paper,the change characteristics of coastline,coastal zone land use/land cover,and tidal flat area were analyzed,based on the methods of waterline and shoreline extraction,and coastal land use classification by using Landsat data from 1973 to 2016 and the analysis methods of GIS.By calculating development intensity index of coastal zone land,the driving mechanism of nature and people was also preliminary analpyzed.The main results were as follows:Firstly,the change characteristics of coastline in study area were analyzed,the results indicated that the length of coastline increased first and then decreased from 1973 to 2016,and the trends of coastline were varied in different districts,mainly affected by sea reclamation.Over the past forty years,the proportion of artificial coastline increased gradually,especially the proportion of construction cofferdam.But the retention of natural coastline in Kinmen was still greater than 80%,the other three areas(Xiang' an,Nan' an and Jinjiang)were less than 10%.For the space variation of coastline,the biggest change of coastline occurred in 2003 to 2016,mainly caused by people activities and expended to the sea,while Xiang'an changing biggest and Kinmen varying least.In addition,under the action of waves and wind,coastline in study area was eroded in different degree,north shore of Weitou Bay and southeast shore of Kinmen were the most significant.Then,the land use/land cover change in coastal zone and the change of tidal flat area from 1993 to 2014 was analyzed using four remote sensing images in 1993,2000,2005,2014.The results indicated that the land use patterns of coastal zone in study area were mainly agricultural land and construction land,followed by artificial wetland,forest land.And the area of construction land increased year by year,agricultural land and artificial wetland reduced gradually,and the increasing parts of construction land mainly derived from agricultural land and artificial wetland.In different periods,the land use patterns of coastal zone in these four districts was different.From 1993 to 2000,the obviously variation of land use change in Xiang'an was that salt fields were tranformed into culture zones.And in Nan'an and Jinjiang,the construction land increased significantly,mainly transformed from agriculture land;Since 2000,construction land of coastal zone in these three districts increasd year by year and Xiang'an increased biggest and mainly derived from agricultural land and artificial wetland(including salt fields and culture zones);While in Nan'an and Jinjiang,construction lands transformed from agricultural land and artificial wetland reclamation.Compared with the three regions,in Kinmen,the change of land use patterns was not significant.From 1993 to 2014,tidal flat area between-1 m and+ 2 m showed the fluctuations characteristics of reduced first,then increased,and finally reduced,and among these four areas tidal flat area in Xiang 'an changed most significantly.Finally,driving forces of affecting coastlines development,coastal zone development intensity and change of the tidal flat area which mainly included natural factors and human factors were discussed.Results shown that the wave functions of natural factors was a major reason of shoreline erosion in study area,and the topography was an important factor restricting land use and distribution pattern of coastal zone in study area.Population and economic development had a close relationship with the variation of coastline and land use pattern of coastal zone.From 1993 to 2014 population of study area increased year by year,and mostly distributed in the coastal area.What is more,increasing amplitude and trend of development intensity index of four districts differed from one another.In the process of urbanization and industrialization,economic structure adjustment and regional development policy significantly influenced the different land use conversion such as construction land,agricultural land and artificial wetlands,and utilization ways of coastline.Spatial and temporal variations of tidal flat wetland area in study area mainly depended on the comparison between the changing rate of upper boundary and the lower boundary of tidal flat.Human activities such as coastal reclamation,marine dredging engineering were the important factors which affected the variation of tidal flat area.