In the contemporary era of global warming there is growing need to detail geographical variations of drought risk so as to investigate the impact of climate change in the densely populated agricultural tract of Gangetic West Bengal (GWB), eastern India. In aim to assess drought jeopardy at the regional scale, the present study deals with temporal trend and spatial pattern of drought during the last century over GWB. Standardized Precipitation Index (SPI) has been used to detail geographical variations of drought intensity, duration, frequency etc. at multiple time steps. Non-parametric Mann-Kendall test and Sen’s slope estimator are used to detect the trends and trends slope. In addition, the article focuses on developing a Composite Drought Risk Index (CDRI) integrating 10 parameters pertaining to drought exposure to detect which regions are most exposed to drought. The results portray a very diverse but consistent picture. The last century exhibits some consecutive deficit and surplus phases and after 1950s the extremity of surplus and deficit as well as drought duration have increased substantially. The impact of drought is expected to be rigorous at or adjacent areas of the western degraded plateau, particularly the northern Rarh and moribund delta where the drought intensities tend to increase while the rainfall as well as recurrence interval of drought tend to decrease. In a nutshell, this work provides evidences demonstrating the extension and intensification of aridity in the northern Rarh plain and Moribund delta. Such altered hydrolo-meteorological system hence calls for review of the agricultural practices and water use in GWB. The CDRI provides a means of obtaining a broad overview of drought risk and supposed to allow decision makers more in-depth investigation.

中文翻译：

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印度东部恒河西孟加拉邦的干旱危害时空评估

在全球变暖的当代时代，越来越需要详细说明干旱风险的地理变化，以便研究气候变化对印度东部恒河西孟加拉邦（GWB）人口稠密的农业区的影响。为了评估区域范围内的干旱危害，本研究探讨了上个世纪GWB上干旱的时间趋势和空间格局。标准化降水指数（SPI）已用于详细描述多个时间步长下干旱强度，持续时间，频率等的地理变化。非参数Mann-Kendall检验和Sen的斜率估计器用于检测趋势和趋势斜率。此外，本文着重于开发综合干旱风险指数（CDRI），该指数整合了与干旱暴露有关的10个参数，以检测哪些地区最容易遭受干旱。结果显示出非常多样化但始终如一的情况。上个世纪出现了一些连续的赤字和盈余阶段，1950年代以后，盈余和赤字的末端以及干旱持续时间大大增加。在西部退化的高原或其附近地区，特别是北部的Rarh和垂死的三角洲，干旱的影响预计会很严峻，那里的干旱强度趋于增加，而降雨和干旱的复发间隔趋于减少。简而言之，这项工作提供了证据，证明了北部拉尔平原和莫里邦德三角洲的干旱扩展和加剧。因此，这种改变后的水文气象系统要求对全球水运机制中的农业做法和用水进行审查。CDRI提供了一种获取干旱风险的广泛概述的方法，并且可以使决策者进行更深入的调查。