Abstract To characterize future drought events over a drought prone area like South Asia is paramount for drought risk mitigation. In this paper, a five-model ensemble mean from CMIP6 was chosen to project drought characteristics in South Asia under the latest SSPs-RCPs emission scenarios (SSP1–2.6, SSP2–4.5, and SSP5–8.5) for the period 2020–2099. Additionally, corresponding scenarios RCP2.6, RCP4.5 and RCP8.5 of CMIP5 were used for comparison and to identify the changes and improvements of CMIP6 over the South Asia. Principle Component Analysis and the Varimax rotation method is used to divided the study area into five homogenous drought sub-regions. Drought duration, frequency, and intensity are analyzed based on the Run theory, and the Standardized Precipitation Evapotranspiration Index (SPEI) at 12-months timescale, and the self-calibrating Palmer Drought Severity Index (sc-PDSI). The Modified Mann-Kendall and Sen's slope method is adopted to detect sub-regional trends in drought characteristics. Results show that significant increases in drought conditions mainly pronounced over the North-West sub-region. Strong increases are projected in the average drought duration and drought frequency. The North-West sub-region is the most vulnerable to face frequent drought events with longer duration with higher intensity. Parts of the South-West, North-Central, and North-East sub-regions will also face more adverse drought conditions in future. The selected model ensemble from CMIP6 has a very robust capability to simulate present climate parameters (precipitation, temperature, and evaporation) and satisfactorily captures drought characteristics in South Asia. These results provide a basis for developing drought adaptation measures for South Asia.

中文翻译：

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通过来自南亚 CMIP6 的多模式集合的未来干旱特征

摘要 描述南亚等干旱易发地区未来干旱事件的特征对于缓解干旱风险至关重要。在本文中，选择来自 CMIP6 的五模型集合平均值来预测 2020-2099 年期间最新 SSPs-RCPs 排放情景（SSP1-2.6、SSP2-4.5 和 SSP5-8.5）下南亚的干旱特征。此外，CMIP5 的相应场景 RCP2.6、RCP4.5 和 RCP8.5 用于比较和识别南亚 CMIP6 的变化和改进。采用主成分分析和Varimax旋转法将研究区划分为5个均质干旱亚区。基于 Run 理论和 12 个月时间尺度的标准化降水蒸散指数 (SPEI) 分析干旱持续时间、频率和强度，和自校准帕尔默干旱严重程度指数 (sc-PDSI)。采用修正的 Mann-Kendall 和 Sen 斜率方法检测干旱特征的次区域趋势。结果表明，干旱条件的显着增加主要在西北次区域显着。平均干旱持续时间和干旱频率预计将大幅增加。西北次区域最容易面临持续时间更长、强度更高的频繁干旱事件。西南、中北部和东北次区域的部分地区未来也将面临更加不利的干旱条件。从 CMIP6 中选择的模型集合具有非常强大的模拟当前气候参数（降水、温度和蒸发）的能力，并令人满意地捕捉了南亚的干旱特征。