Assessing the impact of climate change on rainfall in Thailand by using linear scaling bias correction technique

Abstract

To study climate change at the regional or basin scale, it is imperative to use long-term climate data from the global general circulation model in the analysis of climate change However, the global climate data have a rather coarse resolution or more than 100 square kilometers and highly deviate from the observed climate values. Therefore, before utilizing climate data to assess the impacts of climate change at the country or basin level, it is necessary to correct those biases for assessing the impact of climate change to rainfall condition of Thailand in term of trend of monthly, seasonal, and annual rainfall patterns. This research aimed to assess the impact of climate change to rainfall pattern by applying a technique to correct bias of the global circulation model data by using linear scaling method in conjunction with observed rainfall data from Thai Meteorology Department and 3 CMIP6 global circulation models, namely CESM2, MRI-ESM2-0, BCC-CSM2-MR, GFDL-ESM4, and CanESM. The reliability of bias corrected rainfall data was examined by using correlation coefficient, root mean square error, percentage of biases.