Droughts are one of the multifaceted meteorological disasters affecting agriculture, livestock and water resources worldwide. Pakistan has a semiarid climate system with a high degree of interannual rainfall variability. This study evaluates the applicability and comparison of 3 drought indices (deciles index [DI], standardized precipitation index [SPI] and reconnaissance drought index [RDI]) in Pakistan. Monthly rainfall and temperature data (1981−2017) from 30 weather stations were used to analyze the current status of drought occurrence in terms of severity and magnitude. A nonparametric Mann-Kendall test and Sen’s slope estimates were applied on drought indices to determine the statistical significance and magnitude of the trend. The DI captured the dry episodes in the region well, as Baluchistan and Sindh provinces have been seen to be more susceptible to droughts. The indices of SPI and RDI were well correlated at 3, 6, 9 and 12 mo timescales. Province-level analysis revealed the highest number of drought years during the 3 mo timescale and the lowest number of drought years during the 12 mo timescale. Overall, a linearly increasing trend of SPI and RDI (towards wetness) was observed, whereas the province-level analysis showed a statistically significant trend at the 95% confidence level for Khyber Pakhtunkhwa, Punjab and Sindh in the long-term drought analysis. Moreover, analyses of historical drought years and their intensity have been investigated and compared with a recent long drought episode (1999− 2002). The analysis of historical drought events highlights the challenging nature of drought management in Pakistan. The outcomes of this study would help water resource managers to investigate drought response measures for drought preparedness in the country.

中文翻译：

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巴基斯坦主要干旱地区干旱严重程度和程度的历史分析（1981-2017 年）

干旱是影响全球农业、畜牧业和水资源的多方面气象灾害之一。巴基斯坦属于半干旱气候系统，年际降雨量变化很大。本研究评估了 3 个干旱指数（十分位数指数 [DI]、标准化降水指数 [SPI] 和侦察干旱指数 [RDI]）在巴基斯坦的适用性和比较。使用来自30个气象站的月度降雨和温度数据（1981-2017年）从严重程度和幅度方面分析干旱发生的现状。对干旱指数应用了非参数 Mann-Kendall 检验和 Sen 斜率估计，以确定趋势的统计显着性和幅度。DI 很好地捕捉到了该地区的干旱事件，因为俾路支省和信德省被认为更容易受到干旱的影响。SPI 和 RDI 的指数在 3、6、9 和 12 个月的时间尺度上具有良好的相关性。省级分析显示，3 个月时间尺度内干旱年数最多，12 个月时间尺度内干旱年数最少。总体而言，观察到 SPI 和 RDI（朝向湿度）呈线性增加趋势，而在长期干旱分析中，开伯尔 - 普赫图赫瓦、旁遮普和信德省的省级分析显示，在 95% 置信水平下具有统计显着的趋势。此外，对历史干旱年份及其强度的分析进行了调查，并与最近的长期干旱事件（1999-2002）进行了比较。对历史干旱事件的分析凸显了巴基斯坦干旱管理的挑战性。