MACRO-EVALUATION OF CLIMATE CHANGE IMPACT ON FLOOD CONTROL MEASURES IN JAPAN

Abstract

The authors have estimated the median and the confidence intervals of the rate of increase of following three values, flood discharge, amount of additional work, and probability of exceedance (for representative flood discharge, e.g. 1/100 year flood discharge on the current basic policy for river improvement) for major rivers in Japan under global climate change. For this estimation, the authors calculated the median and the confidence intervals of the rate of increase of the annual maximum rainfall in each geographical region from the results of 20km mesh Global Circulation Model and 5km mesh Regional Climate Model simulations conducted by Meteorological Research Institute, Japan Meteorological Agency, MLIT. The estimation has been conducted for two periods, one for about 30 years later from now, and another around the end of 21^st century. The authors have drawn nationwide figures indicating the results above.