The impact of high wave during 20-23 December 2006 to coastal erosion in the southeastern coast of Thailand

摘要

In past 10 years, coastal change along the coastal of Thailand has been concerned as a serious problem and important causes are both natural factors such as wave energy, wind, current, coastal process and also human activities. This research focuses on study of the wave impact during 20-23 December 2006 to severe erosion areas in Chumporn, Suratthani, Nakhon Si Thammarat, Songkhla, and Narathiwat provinces. The satellite images from SPOT4 and SPOT5 used to analyze shoreline changing. Moreover, oceanographic and meteorological data counted as essential parameters of this event. The results from image analysis present eroded coastal areas, approximately 23.36 hectare at Pakpanang- Nakhon Si Thammarat, 21.92 hectare at Langsuang - Chumporn, 16.64 hectare at Narathus beach and Manow bay-Narathiwat, 13.28 hectare at Donsak-Suratthani, 10.56 hectare at Ranod-Songkhla, 4 hectare at Thachana-Suratthani, and 1.6 hectare at Huasai- Nakhon Si Thammarat. This study found that the erosion severity markedly relate to coastal topography and location. Normally, the transition period from southwest to northeast monsoon induces the high wave and strong wind in the Gulf of Thailand. The wave magnitude depends on additional factors influencing seasonal monsoon. From data recorded during the study period, the strong high air pressure from China prevailed continually over the southern part and the Gulf of Thailand. Additionally, there was also the tropical storm in this area. These additional factors cause higher wave in the area than usual, especially in the western part of the Gulf of Thailand where was directly influenced, and the height of wave was recorded at 2-4 meters.