Spatiotemporal Evolution Characteristics of Coastlines and Driving Force Analysis of the Pearl River Estuary in the Past 40 Years
Coastline change detection is critical for analyzing the rise of sea levels, coastal erosion, harbor siltation, wetland ecological resources, and the offshore environment. Satellite remote sensing technology has a wide application and plays an indispensable role in coastline monitoring. The Pearl River Estuary is one of city groups with the high density population and the most developed economy in China. With the consistent increase of the reclamation and coastal zone exploitation, the coastline changes in the Pearl River Estuary are dramatic. In this paper, a set of Landsat images from 1973 to 2015 were collected to detect the coastline evolutions in the Pearl River Estuary. Firstly, the coastlines were divided into 8 categories and extracted with the aid of remote sensing and geographic information system (GIS) technologies. In addition, the spatiotemporal evolution characteristics of coastline length, categories, and spatial changes were analyzed during the study period. A coastline utilization index was proposed to determine the impact of human activities. Finally, the driving factors of coastline changes were discussed. The results are as follows: ① The total length of coastlines in the Pearl River Estuary increased by 135.46 km, which was equivalent to a growth of 3.15 km per year. The artificial coastline increased significantly, with a net increase of 315.94 km in length. The natural coastline constantly declined, with the most decrease in mud coastline. The change intensity of the coastline length showed remarkable periodicity. It was slow before 1990, peaked from 1990 to 2000, and then weakened after 2000.② The coastline category was changed from natural coastline to artificial coastline in the study period. The natural coastline was the main coastline category before 1990, but the artificial coastline took the lead position thereafter. Among all coastline categories, the proportion of the construction coastline changed most dynamically, which increased from 7.09%in 1973 to 46.49%in 2015.③During the period of 1973–2015, thecoastline showed a prevailing trend of advancing seaward, reaching an annual rate of 39.10 m. The seaward extension rate had significant difference in different area. The greatest extension speed appeared on the coastline between Jiti outlet and Hutiao outlet. The seaward extensions of the coastlines between Modao outlet and Jiti outlet, and between Jiao outlet and Hongqi outlet, were remarkable, too. Other regions had an advancing seaward but with a small magnitude.④In the past 40 years, the coastline utilization index grew stably. The growth rate increased markedly from 1973 to 1995 and changed gently after 1995. The coastline utilization index in the east coast of the Lingding Sea occupied the largest increasing extent because more and more natural coastline had been artificialized.⑤The coastlines in the Pearl River Estuary are affected mainly by human activities, such as outlet renovation, coastal zone construction, and sea farming. Environmental conditions, demographic and economic growth, as well as policies are important driving forces of coastline changes. This study will provide scientific support for the coastline change detection, coastal zone management and sustainable development in the coastal area.
coastlinedynamic changeremote sensing monitoringhuman activitiesPearl River Estuary
NETL
NSTL
万方数据
维普
