| As the largest economic center in China,Shanghai has proposed to develop five new cities in recent years and build a comprehensive node city with radiation belt role in the Yangtze River Delta city cluster,which shows that the coastal zone has an important role in the development of Shanghai.The coastal zone is rich in ecological resources,providing habitat for many rare and endangered species and maintaining the stability of biodiversity.It also provides support for ecosystem services,and coastal wetlands and other coastal areas have important carbon sink functions,thus reducing the impact of climate change.By clarifying the evolution of the coastal zone and preventing it from being polluted,the coastal zone can be used in a sustainable way.However,due to the large number of ports and frequent ship traffic in Shanghai,its coastal zone is threatened by the risk of oil spills from ship transportation activities.These oil spills not only cause direct damage to the local ecosystem,but also have a wide range of impacts on human health,economic activities and social welfare.Therefore,understanding the spatial and temporal characteristics of ecosystem service values during the evolution of the coastal zone and studying the impact of oil spills on the ecosystem service values of the coastal zone can help the study of coastal zone protection and oil spill response countermeasures in China.Therefore,this study aims to promote the management of China’s coastal zone and provide oil spill emergency response support,and takes ecosystem services and oil spill risk as the research scope,and takes the Shanghai coastal zone as the research object.Based on the remote sensing images of four periods and eight scenes in 1990,2000,2010and 2020,the spatial and temporal characteristics of the evolution pattern,ecological sensitivity and ecosystem service values of the Shanghai coastal zone are systematically investigated,and based on this,oil spill simulation experiments are conducted to determine the impact range of oil pollution and the impact on ecosystem services,to improve the emergency management of oil spill risk in the coastal zone,to reduce oil spill This paper aims to improve the emergency management of oil spill risk in the coastal zone,reduce the damage caused by oil spills,and maintain the stability of the natural environment in Shanghai.This paper firstly identifies and extracts the shorelines in the study area based on Landsat remote sensing image data,produces vector maps of the shorelines for four periods of 1990,2000,2010 and 2020,and explores the length change and intensity of shoreline variation.Based on the vector data of Globe Land 30,we improved the land use data of Shanghai coastal zone and reclassified the thematic information of the study area by Arc GIS 10.7.We classified the land use in the study area into six categories:forest land,cropland,grassland,wetland,construction land and water bodies,and grasped the amount of land change,distribution of land use types and land transfer in the study area.And based on the six evaluation factors of slope,slope direction,elevation,vegetation cover,land use type and water body buffer,we study each ecological sensitivity and comprehensive ecological sensitivity of Shanghai coastal zone.Then,according to the availability of data,ecosystem services were classified into four categories of supply services,regulating services,cultural services and supporting services to quantitatively study the Shanghai coastal zone.The ecosystem service value model of the study coastal zone was established through the assessment method of equivalent factors,and this was used to quantify the total ESV,the ESV of the 9 service functions and the spatial distribution of the unit ESV in 2000,2010 and 2020,and the single ecosystem service function with the highest contribution was selected for analysis to reveal the characteristics of changes in ESV at temporal and spatial scales.Finally,based on the ship collision reports of the Maritime Bureau and the literature research on oil spill statistics in the past years,four high frequency points of oil spills along the Shanghai coast were sorted out.Through the"oil particle"model,the oil spill experiments were conducted for four seasons of the year with small and large tides and eight wind directions under large and small tides,and the time was selected as 2021,and the spreading time of each oil spill was 72 h.The oil particle drifting onshore particles and active particles were recorded for each accident to determine the pollution area and trajectory.And the shoreline oil spill sensitivity map was drawn according to the shoreline type,and the oil spill risk was analyzed in terms of both sensitivity and ecosystem service value by combining the oil spill dispersion and impact area,so as to formulate the oil spill prevention and control plan,reduce the emergency response time after the oil spill occurred,reasonably optimize the configuration content,and minimize or avoid the ecological or economic loss caused by the oil spill.The main conclusions of the study are as follows:(1)The change of Shanghai coastline length specifically shows an increase followed by a slow decrease to an increase,but an overall increase of 11.24 km in 2020 compared with 1990.among them,the coastline length of Changxing Island and Hengsha Island basically remained unchanged during 1990-2000,but increased rapidly during 2000-2020,with a ten-year increase of 13.47 km and 45.57 km,respectively.The overall shoreline variation of Chongming Island is negative due to the influence of human activities in the change,while the rest of the area has increased.(2)With the increase of land area in Shanghai coastal zone,coupled with the intensification of human activities,a large number of sea areas were converted into wetlands and enclosed waters,mainly concentrated in Pudong New Area,Chongming East Beach and the tail of Huangsha Island.156.85km~2 of water bodies and 144.15km~2of wetlands were increased in total between 2000 and 2020.taking the increase of land from 1990 to 2000 as an example,a large number of original water bodies and mudflats were transformed into arable land and construction land,and by 2020,36.79km~2 of water bodies were transformed into arable land and 12.62km~2 of mudflats were transformed into construction land.Meanwhile,due to the increase in intensity of human activities and coastal engineering,the land use area utilization of coastal zone has changed significantly,and the main increase area types are water bodies and wetlands,but finally turned out to be arable land and construction land.(3)The ESV values in 2000,2010 and 2020 are 13.02×10~8,29.89×10~8 and34.41×10~8 CNY,respectively,with the highest contribution from water bodies and wetlands.Due to the small increase of grassland and woodland,their ESV changes are not significant.The overall ESV of Shanghai coastal zone increased during the study period due to land expansion,but the ESV of wetlands decreased by 28.59%between2010 and 2020.In terms of spatial distribution,the ESV distribution of Shanghai coastal zone showed a movement from high-value areas to low-value areas,and in 2020,areas with extremely high ESV per unit area basically disappeared.In addition,the decrease of wetlands and water bodies is consistent with the disappearance of very high ESV values,and the increase of a large amount of construction land and the decrease of wetland ecosystems are the main reasons for the change of ESV in Shanghai coastal zone.(4)It is found that oil particles are mainly influenced by wind.According to the ideal experiment,we can know that when the oil spill occurs near Wusongkou wharf,the south wind will all affect Qingcaosha reservoir,due to the key concern.In addition,the ecological sensitivity is high in the vicinity of Pudong New Area Binjiang Forest Park,which will be affected by the oil spill occurring near Wusongkou and Waigaoqiao terminals.When an oil spill occurs near the South Channel waterway,the oil spill sensitivity is high because part of the shoreline in Pudong is silty shoreline,so the oil should be treated in time to prevent the oil from entering the silt and then being difficult to treat.The research in this thesis provides help for coastal zone protection and oil spill response,and gives a basis for developing a reasonable environmental management approach.However,the research can still be improved in the future by refining the types of land use types and compiling dynamic oil spill risk mapping pieces. |
