Kang Hyunwoo, Sridhar Venkataramana, Ali Syed A
Department of Biological Systems Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
Department of Biological Systems Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
Sci Total Environ. 2022 Sep 10;838(Pt 2):155845. doi: 10.1016/j.scitotenv.2022.155845. Epub 2022 May 10.
Recent drought events in the Mekong River Basin (MRB) have resulted in devastating environmental and economic losses, and climate change and human-induced alterations have exacerbated drought conditions. Using hydrologic models and multiple climate change scenarios, this study quantified the future climate change impacts on conventional and flash drought conditions in the MRB. The Soil and Water Assessment Tool (SWAT) and Variable Infiltration Capacity (VIC) models were applied to estimate long-term drought indices for conventional and flash drought conditions over historical and future periods (1966-2099), using two emission scenarios (RCP 4.5 and RCP8.5), and four climate models from the Coupled Model Intercomparison Project Phase 5 (CMIP5). For the conventional drought assessment, monthly scale drought indices were estimated, and pentad-scale (5 days) drought indices were computed for the flash drought evaluations. There were overall increases in droughts from the SWAT model for the conventional drought conditions and overall decreases from the VIC model. For the flash drought conditions, the SWAT-driven drought indices showed overall increases in drought occurrences (up to 165%). On the contrary, the VIC-driven drought indices presented decreases in drought occurrences (up to -44%). The conventional and flash drought evaluations differ between these models as they partition the water budget, specifically soil moisture differently. We conclude that the proposed framework, which includes hydrologic models, various emission scenarios, and projections, allows us to assess the various perspectives on drought conditions. Basin countries have differential impacts, so targeted future adaptation strategy is required.
湄公河流域（MRB）近期发生的干旱事件已造成了毁灭性的环境和经济损失，而气候变化和人为因素加剧了干旱状况。本研究利用水文模型和多种气候变化情景，量化了未来气候变化对湄公河流域传统干旱和骤发干旱状况的影响。应用土壤和水资源评估工具（SWAT）模型和可变下渗能力（VIC）模型，采用两种排放情景（RCP 4.5和RCP8.5）以及耦合模式比较计划第5阶段（CMIP5）的四个气候模型，估算历史时期和未来时期（1966 - 2099年）传统干旱和骤发干旱状况的长期干旱指数。对于传统干旱评估，估算月尺度干旱指数，对于骤发干旱评估，计算五天尺度（5天）干旱指数。SWAT模型显示传统干旱状况下干旱总体增加，而VIC模型显示总体减少。对于骤发干旱状况，SWAT驱动的干旱指数显示干旱发生次数总体增加（高达165%）。相反，VIC驱动的干旱指数显示干旱发生次数减少（高达 - 44%）。这些模型在传统干旱和骤发干旱评估方面存在差异，因为它们划分水分收支的方式不同，特别是土壤水分的划分方式。我们得出结论，所提出的框架，包括水文模型、各种排放情景和预测，使我们能够评估干旱状况的不同观点。流域各国受到的影响不同，因此需要有针对性的未来适应策略。
