Potential investigation of SAR data in monitoring island and its surrounding environment: 8-year dynamic monitoring of South five-island in Miaodao archipelago of China
Xiaolong WANG(1) and Jie ZHANG(2)
Institute of Oceanology, Chinese Academy of Scienc,
(2) First Institute of Oceanography,SOA, 6,Xian-Xia-Ling Road, High-Tech Park, 266061,Qingdao, China
Island is important marine resource. For the complex environmental dynamics dominated by wave and tide and increased human activities, there is a great need for high resolution, synoptic information on the dynamic changes of it. This study aims to discuss the ability and demonstrate the application in monitoring and mapping the dynamic changes of island and its surrounding marine environments using ERS SAR imagery. Data in support of the research were obtained from field campaigns from 1997 to 2005. The focus is on the South five-island area of Miaodao archipelago in the intersection of Bohai sea and Yellow sea. Based on the sensitivity of SAR to the edge, an edge detection approach is developed for the coastline monitoring. Using the texture analysis method, statistical texture features of SAR images combined with the varied statistical windows and directions are calculated and selected for objects detection. Through matching the derived results with the ground truthing, potentials of SAR imagery in monitoring island and its inshore environments are discussed and analyzed, and a conclusion that the extraction accuracy of SAR in island monitoring can reach 80 percent or more has been drawn. In the case research, 8-year dynamic changes of the South five-island and its surrounding marine environments, form 1997 to 2005, have been studied by the time-series SAR data. Information of the environmental changes in this region, including terrestrial environments, coastline and inshore conditions, is derived and the causes are analyzed.