Climate change is progressing and is now one of the most important global challenges for humanities. Water resources management is one of the key challenges to reduce disaster risk. In Northern Thailand, flood and drought have always occurred because of the climate change impact and non-systematic management in the conjunctive use of both sources of water. Therefore, this study aims to assess the climate change impact on surface water and groundwater of the Yom and Nan river basins, located in the upper part of Thailand. The surface water and groundwater regimes are generated by a fully coupled SWAT-MODFLOW model. The future climate scenarios are considered from the Representative Concentration Pathways (RCPs) 2.6 and 8.5, presented by the Coupled Model Intercomparison Project Phase 5 (CMIP5), in order to mainly focus on the minimum and maximum Green House Gas (GHG) emissions scenarios during the near future (2021–2045) periods. The results show that the average annual air temperature rises by approximately 0.5–0.6 °C and 0.9–1.0 °C under the minimum (RCP 2.6) and maximum (RCP 8.5) GHG emission scenarios, respectively. The annual rainfall, obtained from both scenarios, increased by the same range of 20–200 mm/year, on average. The summation of surface water (water yield) and groundwater recharge (water percolation) in the Yom river basin decreased by 443.98 and 316.77 million m3/year under the RCPs 2.6 and 8.5, respectively. While, in the Nan river basin, it is projected to increase by 355 million m3/year under RCP 2.6 but decrease by 20.79 million m3/year under RCP 8.5. These quantitative changes can directly impact water availability when evaluating the water demand for consumption, industry, and agriculture.

中文翻译：

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气候变化对泰国北部地表水和地下水补给的影响

气候变化正在取得进展，现在已成为人文学科最重要的全球挑战之一。水资源管理是减少灾害风险的主要挑战之一。在泰国北部，由于气候变化的影响和两种水源联合使用的非系统管理，洪水和干旱总是发生。因此，本研究旨在评估气候变化对位于泰国上部的 Yom 和 Nan 河流域地表水和地下水的影响。地表水和地下水状况由完全耦合的 SWAT-MODFLOW 模型生成。从耦合模型比对项目第 5 阶段 (CMIP5) 提出的代表性浓度路径 (RCP) 2.6 和 8.5 中考虑未来气候情景，主要关注近期（2021-2045）期间的最小和最大温室气体（GHG）排放情景。结果表明，在最小 (RCP 2.6) 和最大 (RCP 8.5) 温室气体排放情景下，年平均气温分别上升约 0.5–0.6 °C 和 0.9–1.0 °C。从两种情景中获得的年降雨量平均增加了 20-200 毫米/年的相同范围。在 RCP 2.6 和 8.5 下，Yom 河流域地表水（产水量）和地下水补给（水渗透）的总和分别减少了 443.98 和 31677 万立方米/年。而在南河流域，在 RCP 2.6 下预计将增加 3.55 亿立方米/年，但在 RCP 8.5 下预计将减少 2079 万立方米/年。