Impact assessment of climate change on drought risk and quantification of its uncertainty by using large ensemble climate data set

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K08004
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Rural environmental engineering/Planning
• Research Institution: Okayama University
• Principal Investigator: Kudo Ryoji 岡山大学, 環境生命科学研究科, 准教授 (40600804)
• Co-Investigator(Kenkyū-buntansha): 近森 秀高 岡山大学, 環境生命科学研究科, 教授 (40217229)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 大規模アンサンブルデータ / 渇水リスク / 気候変動 / 不確実性

Outline of Final Research Achievements

This study addressed the uncertainty in climate change impact on drought risk caused by the natural variability which hydrological indices naturally have, using d4PDF, large-ensemble climate dataset. We used three indices for the assessment: 10-year drought discharges during puddling and heading periods for drought risk, and 10-year daily discharge for flood risk. To detect influence of the natural variability, we calculated 9,000 pattern change ratio of each index using 100 ensemble members for present climate and 90 ensemble members for future climate.
The results show the large distribution of the change ratio for each index except 10-year drought discharge during puddling period in heavy snow region; this means that in the assessment on extreme events such as flood and drought, the assessment results may include both increasing and decreasing trends due to the natural variability, the uncertainty in climate change impact caused by natural variability are inevitable.

Free Research Field

水文学

Academic Significance and Societal Importance of the Research Achievements

極端現象である渇水リスクの影響評価には自然変動による不確実性が大きいなど多く課題が残されているが，本研究で示したd4PDFを用いた影響評価法を用いることで，これまで定量化が困難であった渇水リスクに対する気候変動影響評価について確率情報を付加する形で影響評価結果の提供が可能となり，将来の農業用の水資源計画および水利施設管理への有用な情報を提供できる．