Abstract

This study provides an evaluation of the past, present, and future spatiotemporal variability of droughts in the Bundelkhand region of central India. The assessment has been made by analyzing the existing (1951–2018) drought dynamics with gridded observational and reanalysis datasets. The future projection is presented using a multi-model ensemble from 21 simulations of regional climate model over CORDEX South-Asia domain under the highest carbon concentration, i.e., RCP8.5 emission scenario. The Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) indices are used for short and long-term monitoring of droughts. Spatiotemporal statistical analysis is performed to examine the relationship between drought indices, i.e., SPI, SPEI and driving parameters such as temperature, precipitation, etc. It is noticed that the frequency of drought has increased since the beginning of the 21st century. In particular, the northern part of the Bundelkhand region is more vulnerable to drought due to overall less precipitation and more temperature. The composite analysis of drought year indicates that moisture-laden wind from the Arabian Sea branch generally weakened in monsoon season. Teleconnections of drought over Bundelkhand region reveal that nearly 40% of the droughts are linked to El-Nino events that have become stronger in recent decades. The model ensemble realistically represents the regional climate reasonably well over the region. The projected change in near future drought shows more frequent events using both SPI and SPEI indices that are also detected in the observational analysis.

Research Highlights

• The Northern region of Bundelkhand is more prone to drought due to high temperature and low precipitation.

• The region receives most of its precipitation from Arabian Sea branch of monsoon winds that generally weakened in drought composite years.

• About 40% of drought variability is teleconnected with El–Nino years that has become more stronger in recent decades

• The ensemble of RCM simulations over CORDEX South–Asian domain indicates that the drought events are projected to be more frequent in near future.

中文翻译：

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了解 Bundelkhand 地区的干旱动态和变异性

摘要

本研究评估了印度中部邦德尔坎德地区过去、现在和未来干旱的时空变化。该评估是通过使用网格化观测和再分析数据集分析现有（1951-2018 年）干旱动态进行的。在最高碳浓度下，即 RCP8.5 排放情景下，使用来自 CORDEX 南亚域区域气候模型的 21 个模拟的多模型集合来呈现未来预测。标准化降水指数 (SPI) 和标准化降水蒸散指数 (SPEI) 指数用于干旱的短期和长期监测。进行时空统计分析以检查干旱指数（即SPI、SPEI）与温度、降水等驱动参数之间的关系。值得注意的是，自21世纪初以来，干旱发生的频率有所增加。尤其是本德尔坎德邦北部地区，由于总体降水量较少且温度较高，因此更容易受到干旱的影响。干旱年综合分析表明，阿拉伯海支带湿气在季风季节普遍减弱。Bundelkhand 地区干旱的遥相关显示，近 40% 的干旱与近几十年来变得更加强烈的厄尔尼诺现象有关。该模型集合真实地代表了该地区的区域气候。使用在观测分析中也检测到的 SPI 和 SPEI 指数，近期干旱的预测变化显示了更频繁的事件。

研究亮点

• 本德尔坎德邦北部地区由于高温少雨，更容易发生干旱。

• 该地区的大部分降水来自阿拉伯海季风的分支，这些季风在干旱复合年普遍减弱。

• 大约 40% 的干旱变异与近几十年来变得更加强烈的厄尔尼诺年有关

• 对 CORDEX 南亚域的 RCM 模拟集合表明，干旱事件预计在不久的将来会更加频繁。