東南アジア熱帯地域における降雨極値の空間解析

抄録

The objective of this study is to estimate the daily extreme precipitation distribution in an Asian monsoon region considering orographic precipitation in mountainous areas. For this purpose, the APHRODITE (the activities of the Asian Precipitation Highly Resolved Observational Data Integration Towards the Evaluation of Water Resources) dataset and precipitation observations from 150 rain gauges throughout Thailand were used as the main input. Firstly, a bias-correction for undervalued precipitation in the APHRODITE dataset was conducted compared with the rain gauge data. Secondly, a frequency analysis for estimating the extreme precipitation for return periods was performed based on the bias-corrected APHRODITE dataset and the rain gauge data. For taking orographic precipitation effect into account, a regression relationship among the calculated extreme precipitation, elevation and latitude was developed using the 150 rain gauge data. Incorporating the effect of orographic precipitation, the extreme precipitation distribution was improved to show the characteristic of precipitation in mountainous areas. The improved precipitation distribution was validated reviewing past studies about orographic precipitation in Thailand.