Abstract

The uneven hydro-climatic changes and droughts have significantly affected the socioeconomic condition of people dependent on the Indus basin, Pakistan. This study aims to examine the annual and seasonal hydro-climatic trends for the Upper Indus Basin (UIB), Middle Indus Basin (MIB) and Lower Indus Basin (LIB). The mean monthly data from 44 meteorological and 30 hydrological stations have been analyzed. The Mann Kendall test, Spearman’s rho test, linear trend estimation method and Van Belle and Hughes test have been used to perform analysis of hydro-climatic trends. The Standardized Precipitation Index (SPI), Sequential Mann Kendall test and rescaled range analysis have been introduced to detect the seasonal and annual drought. The results showed that significant warming has been observed throughout the Indus basin. The spring precipitation decreased significantly in the UIB with the maximum decrease of 5.3 mm/year. The streamflow of UIB has presented significant increasing trends on annual basis and spring season due to significant warming and glacier melt. The streamflow of MIB presented a significant increase in spring, and it decreased in summer, which can be related to significant warming. The annual precipitation of LIB presented significant increasing trends, and a similar trend has been observed in autumn. However, the LIB showed decreasing streamflow trends on an annual and seasonal basis which is possible due to significant warming trends and water regulation in upstream. The Hurst index value indicates that the Indus basin is expected to maintain current trends and the degree of drought is expected to increase in the future.

中文翻译：

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确定巴基斯坦印度河流域水文和气候变量的年度和季节性趋势

摘要

不平衡的水文气候变化和干旱严重影响了依赖巴基斯坦印度河盆地的人们的社会经济状况。这项研究旨在检验上印度河流域（UIB），中印度河流域（MIB）和下印度河流域（LIB）的年度和季节性水气候趋势。分析了来自44个气象站和30个水文站的月平均数据。Mann Kendall检验，Spearman的rho检验，线性趋势估计方法以及Van Belle和Hughes检验已用于进行水文气候趋势分析。引入了标准降水指数（SPI），顺序Mann Kendall检验和重定范围分析来检测季节性和年度干旱。结果表明，在整个印度河流域都观测到明显的变暖。UIB的春季降水显着减少，最大减少量为5.3 mm /年。由于明显的变暖和冰川融化，UIB的流量在年度和春季呈现出显着的增长趋势。MIB的流量在春季显着增加，而在夏季则减少，这可能与明显的变暖有关。LIB的年降水量呈现出显着的增长趋势，并且在秋季也观察到了类似的趋势。但是，LIB的年度和季节流量呈下降趋势，这可能是由于明显的变暖趋势和上游的水量调节。赫斯特（Hurst）指数值表明，预计印度河流域将保持当前趋势，并且未来干旱程度有望增加。