Spatio-temporal Variation And Driving Analysis Of Coastal Zone In Yantai In Recent 30 Years

Yantai is a key port city in the "Belt and Road Initiative" national strategy and an important node city in the economic circle around the Bohai Sea.As one of the open coastal cities in China,with the 909 kilometers coastline,which is the central area in the Northeast Asian economic circle to communicate with the transnational economic development zone of China,Japan and South Korea.Yantai connects the trade between Asia and Europe in the west,radiates the transnational economic and trade circle of Japan and South Korea to the east,and connects the economic and trade exchanges between North China and Northeast China in the north and south.Marine economic industry has become its main industry,which is mainly distributed in port transportation,ship machinery manufacturing,fishery breeding,tourism and other fields.With the development of social economy,the unreasonable development of coastal zone is also growing gradually.Therefore,it is of practical significance to grasp the present situation of the temporal and spatial distribution of Yantai coastal zone,analyze the changing law of coastal zone,and analyze its driving factors,so as to explore the direction of development and utilization of Yantai coastal zone in the future.It is of practical significance to realize the circular development of marine economy and promote the scientific planning of coastal zone in Yantai.Based on Landsat TM and GF-2 remote sensing data and using the method of deep learning,this study extracted the information of Yantai coastal zone in 1990,2000,2010,2014 and 2018 respectively,compared and analyzed the temporal and spatial variation of Yantai coastal zone in recent 30 years,and analyzed its driving force.The results are as follows:(1)The time series feature reconstruction method based on deep learning can extract the coastal zone information of Yantai.Compared with other classifiers,the overall classification accuracy is 91.32%,and higher precision results can be obtained.It can be seen that this method can effectively improve the classification accuracy of complex features and is beneficial to the classification and recognition of local objects with few samples.(2)In the past 30 years,the surface cover of Yantai coastal zone is mainly natural surface,including grass/forest land,water area and planting land,which account for 58.62% of the total coastal area.(3)From the perspective of time sequence,the change trend of different land use types is different in different periods.From 1990 to 2000,the area of cultivated land,houses,roads,hardened surface and water area showed an increasing trend;from 2000 to 2010,the area of houses,roads,hardened surface and water area showed an increasing trend;from 2010 to 2018,the area of grass/forest land,roads,hardened surface and bare land showed an increasing trend.Generally speaking,the most obvious increase of surface cover in Yantai coastal zone is grass/woodland.(4)In terms of spatial distribution,grass / forest land was mainly distributed in Muping District and Longkou City in 1990,and the distribution centers of grass / forest land in 2018 were in Laizhou City,Muping District and Longkou City;in 1990,cultivated land was mainly distributed in Haiyang City and Laizhou City.The main distribution areas of cultivated land are Penglai City and Haiyang City.(5)The change rates of different feature types are also different in different periods.From 1990 to 2000,the roads surface increased the fastest,with an annual change rate of20.86%,while the bare land decreased the fastest,with an annual change rate of 6.3%.From2000 to 2010,the hardened surface area increased the fastest,with an annual change rate of2.94%;the houses increase rate was 2.25%;and the fastest decline was in bare land,with an annual change rate of 5.29%.From 2010 to 2014,the hardened surface increased more,with an annual change rate of 54.44%;the fastest decline was cultivated land,with an annual change rate of 8.4%.From 2014 to 2018,the fastest growth rate was the roads,with an annual change rate of 22.71%.From 1990 to 2018,the hardened surface grew the fastest,with an annual change rate of 32.66%;the fastest decline was bare land,with an annual change rate of1.97%.(6)The change of surface cover in Yantai coastal zone is affected by both natural environment and social and economic development.Natural factors drive the basic types of coastal zone,and population and economy directly affect the change and rate of land use in coastal zone.Policy orientation is an important factor in the spatio-temporal change of land use.