領域気候モデルとバイアス補正手法に起因する不確実性が早明浦ダム貯水量将来変化の推定に与える影響

井芹 慶彦^*，藤村 和正^**，村上 雅博^***，鼎 信次郎^*
（^*東京工業大学大学院理工学研究科，^**明星大学理工学部，^***高知工科大学環境理工学群）

Estimation of future change of water storage in Sameura reservoir with considering uncertainties stemming from regional climate models and bias correction methods

Yoshihiko ISERI^*, Kazumasa FUJIMURA^**, Masahiro MURAKAMI^*** and Shinjiro KANAE^*
*Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
^**Department of Interdisciplinary Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino, Tokyo 191-8506, Japan
^***School of Environmental Science and Engineering, Kochi University of Technology, 185
Miyanokuchi, Tosayamada-cho, Kami-gun, Kochi 782-8502, Japan

Abstract

Future change of water cycle could cause serious impacts to human society. Outputs from climate models are often used to make future climate scenarios, which are used as input for impact assessment model. In addition, many impact studies carry out bias correction of climate model outputs so that input for impact model is quantitatively consistent with observation. This study employs three bias correction methods against daily precipitation outputs from three regional climate models, in order to evaluate uncertainties of future scenarios stemming from choice of regional climate models and bias correction methods. The result indicated precipitation scenario's uncertainty from regional climate models and bias correction methods is higher in heavy rainfall season. In addition, we developed impact model for Sameura river basin, and utilized those precipitation scenarios as input for our impact model. The result suggested water storage in Sameura reservoir during non-irrigation season might be higher in the future period of 2091-2100. It should be noted that there are some limitations in simulation design of this study (i.e. limited number of Global Climate models, bias correction methods, etc), and thus, further improvement of simulation conditions would be necessary for more reliable estimations.

Key words: Sameura river basin, regional climate model, bias correction, precipitation