원격탐사자료를 이용한 마이크로네시아 코스레의 해안선 변화 분석

Abstract

The equatorial Pacific island nations are being threatened by coastal erosion and flooding caused by the global climate change and sea level rise. Actually, 80% Coastal regions of Kosrae, Federated States of Micronesia have high exposure to the effect of coastal erosion. This research aims to analyze long-term coastline changes using remote sensing(RS) data. In this research, vegetation boundary line uses for analysis instead of actual coastline because of rare tide data and low quality of aerial photographs. Aerial photographs of 1944, 1976, and satellite image of 2001, 2003, 2006 are used for extracting the vegetation boundary line. In the Malem area, southeastern Kosrae coastline had retreated over 50m from 1944 to 1976 and 20m between 1976 and 2006, respectively. The Malem area is one of severe eroded areas mentioned by the local government of Kosrae. However, In Tafunsak area, north of Kosrae, significant changes were not detected in RS data. Also, Yela mangrove forest, north-west coastal area of Kosrae, rather a little had prograded than retreat since 1944. These spatial differences of coastline retreat and progradation suggest that global sea-level rising does not give same effect to all coast although relative small island. Coastal erosion can be affected by several factors such as distribution of waves strength, effect of coast prevention by Mangrove forest and coastal structures. the effect of coastal erosion. This research aims to analyze long-term coastline changes using remote sensing(RS) data. In this research, vegetation boundary line uses for analysis instead of actual coastline because of rare tide data and low quality of aerial photographs. Aerial photographs of 1944, 1976, and satellite image of 2001, 2003, 2006 are used for extracting the vegetation boundary line. In the Malem area, southeastern Kosrae coastline had retreated over 50m from 1944 to 1976 and 20m between 1976 and 2006, respectively. The Malem area is one of severe eroded areas mentioned by the local government of Kosrae. However, In Tafunsak area, north of Kosrae, significant changes were not detected in RS data. Also, Yela mangrove forest, north-west coastal area of Kosrae, rather a little had prograded than retreat since 1944. These spatial differences of coastline retreat and progradation suggest that global sea-level rising does not give same effect to all coast although relative small island. Coastal erosion can be affected by several factors such as distribution of waves strength, effect of coast prevention by Mangrove forest and coastal structures.