The Projection of Shoreline Based on the MIROC-ESM Climate Model along the Coast of Thailand

Thailand is littoral country with the coastal zone including the Gulf of Thailand and the Andaman Sea. They are economic important areas where 23 provinces are located with approximately 12 millions of population living in this areas. The coasts are characterized by geologic nature of landforms as sandy beach and dunes, coastal wetland, rocky coast, cliff coast and islands. Thailand's coast has been developed significantly since the last 3 decades; moreover, population growth and the demand for coastal living are ongoing pressures. Therefore, the potential impacts of climate change on existing coastal hazards are likely to increase. The impacts of sea level rise are probable to lead to the greater coastal inundation and erosion that may cause damage and loss to property, infrastructure and the environment. Although Thailand has approximately 2,700 km of shoreline, few researches have been conducted on coastal zone impacts and adaptations to climate change until now. Therefore, this study aimed to project the shoreline change along Thailand's coast due to the global sea level rise based on the climate scenario MIROC-ESM RCP4.5. The projection shoreline analysed by Bruun based on the assumption that in response to sea level rise, shore profiles would respond by acting to maintain their morphology relative to still water levels. It is a simple geometric model of nearshore profile evolution under rising sea level that is often assumed to work on all sandy shorelines. Moreover, the influences of land subsidence associated with sea level rise were taken into account in this study. The observed data as well as secondary data were used for modelling the 23 representative sandy beaches along the coast. Beach slope were observed as well as grain size sampling for model input. Wave buoys located along the coast were used for wave height and period detection. The results indicated shoreline retreat more than 2 m at the end of century when the land subsidence was not considered. On the other hand the effect of subsidence can drive shoreline to be recessed more than 20 m at the same location. Needless to say, sea level rise result in radical change to our coastal area. It should be taken into account for coastal disaster management viewpoint in the near future.