Hindawi Advances in Meteorology Volume 2020, Article ID 5852760, 18 pages https://doi.org/10.1155/2020/5852760 Research Article Spatiotemporal Variability in the Hydrometeorological Time-Series over Upper Indus River Basin of Pakistan Muhammad Yaseen,1 Ijaz Ahmad ,2 Jiali Guo ,3 Muhammad Imran Azam,3 and Yasir Latif4 1Centre for Integrated Mountain Research (CIMR), University of the Punjab, Lahore 54590, Pakistan 2Centre of Excellence in Water Resources Engineering, University of Engineering and Technology, Lahore 54890, Pakistan 3College of Hydraulic and Environmental Engineering, China .ree Gorges University, Yichang 443002, China 4Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, University of Chinese Academy of Sciences, Beijing 100101, China Correspondence should be addressed to Jiali Guo; [email protected] Received 2 November 2019; Revised 1 January 2020; Accepted 10 January 2020; Published 30 April 2020 Academic Editor: Anthony R. Lupo Copyright © 2020 Muhammad Yaseen et al. (is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (is paper investigates the spatiotemporal variability in hydrometeorological time-series to evaluate the current and future scenarios of water resources availability from upper Indus basin (UIB). Mann–Kendall and Sen’s slope estimator tests were used to analyze the variability in the temperature, precipitation, and streamflow time-series data at 27 meteorological stations and 34 hydrological stations for the period of 1963 to 2014. (e time-series data of entire study period were divided into two equal subseries of 26 years each (1963–1988 and 1989–2014) to assess the overlapping aspect of climate change acceleration over UIB. (e results showed a warming pattern at low altitude stations, while a cooling tendency was detected at high-altitude stations. An increase in streamflow was detected during winter and spring seasons at all hydrological stations, whereas the streamflow in summer and autumn seasons exhibited decreasing trends. (e annual precipitation showed a significant decreasing trend at ten stations, while a significant increasing trend was observed at Kohat station during second subseries of the study period. (e most significant winter drying trends were observed at Gupis, Chitral, Garidopatta, and Naran stations of magnitude of 47%, 13%, 25%, and 18%, respectively, during the second subseries. (e annual runoff exhibited significant deceasing trends over Jhelum subbasin at Azad Pattan, Chinari, Domel Kohala, Muzaffarabad, and Palote, while within Indus basin at Chahan, Gurriala, Khairabad, Karora, and Kalam in the second time-series. It is believed that the results of this study will be helpful for the decision-makers to develop strategies for planning and development of future water resources projects. 1. Introduction heavy population growth, there is a great stress on water resources to meet the food and fiber requirement for the Tibetan Plateau comprises three major mountainous areas of people. (e satisfaction of irrigation system, domestic Asia, that is, Hindukush, Karakoram, and Himalaya (HKH), consumption, and hydropower needs are dependent on also known as the “third pole” or “roof of the world” because water resources from the UIB and its tributaries. (e huge of the massive volumes of recurrent snow and glacial ice river basins of south and southeast Asia rely on summer storage in its high-altitude basins [1, 2]. (e upper Indus monsoonal wet regimes downstream, but the UIB is de- basin (UIB) encompasses a huge constituency of hilly areas, pendent on melted water from glaciers and snow-fed and water resources originating from this region are of catchments [3]. If anthropogenic interventions causing decisive significance to the interests of Pakistan. (e upper greenhouse gas emissions into the atmosphere persist, the Indus river system is of high importance to sustainable water average global surface temperature may rise from 0.2 to supply for large populations located in the lower reaches of 0.5°C/decade in the next few decades over UIB [4]. (is Indus river in Pakistan. Being an agricultural country with temperature upsurge in the Himalayan region is greater than 2 Advances in Meteorology the average global rise of 0.74°C over the last century [5]. flows from the highest central Karakoram watersheds over Large-scale warming of the earth surface over the last ten the past two decades and suggested that much winter pre- decades or even more is also indicated by several researchers cipitation is going into long-term storage by glacier surges. [6–8]. Not only did such high-scale warming affect the global Khattak et al. [17] showed increasing trends in the winter circulation patterns but also direct affects occur in local flows with the increase of mean maximum winter tem- climatic settings with changes in distribution and charac- perature and a negative trend in mean summer flows. Sharif teristics of precipitation and temperature [9]. Changes vary et al. [26] observed some effect of timing and magnitude of in space and time domains as affected by local climatic and flows by climate change in the high elevated areas of the UIB. topographic settings [10–13]. (ese spatiotemporal varia- Flows are affected by initial snowpack conditions by winter tions in the climatic variables have motivated this study in precipitation at the beginning of the spring snow melt de- which we aim to assess possible acceleration of climate rived streamflow and trends in temperature that differ changes and related hydrological impacts over UIB. seasonally. It is noted that findings of these studies generally Numerous climate change studies have been carried out rely on time-series consisting of several decades, thus pre- over the UIB. For instance, significant decreasing temper- venting assessment of aspects of acceleration of climate ature trends were detected during the monsoon season and changes and related hydrological impacts. It is expected that warming during the premonsoon season [14–16]. Moreover, the global climate change may have significant impacts on warming winter and cooling summer trends were found the regime of hydrologic extremes. Hence, the design and over UIB; however, these trends lack a definite pattern of management of water resources systems should be adopted precipitation [17, 18]. However, Bocchiola and Diolaiuti [16] to changing hydrologic extremes. However, most of the argued that winter warming and summer cooling trends studies conducted over UIB were restricted to limited were overstated in earlier studies and were only restricted to number of stations and data lengths. (erefore, the number Gilgit and Bunji stations, respectively. (ey reported in- of hydrometeorological stations was extended depending on creasing (insignificant) precipitation trends over the Chitral the available data and coverage of entire Indus, Kabul, and and Northwest Karakoram regions and a drying pattern over Jhelum river basins was incorporated to investigate the the UIB. Some recent studies have reported general in- variations in the hydrometeorological time-series. creasing temperature trends during the premonsoon instead (is study investigates the spatiotemporal variability in during December–February. Latif et al. [19] stated that the the hydrometeorological time-series data and hydrological decreasing precipitation trends dominated over the UIB impacts over UIB by using Mann–Kendall and Sen’s slope spatially and temporally. estimator tests. Moreover, the impacts of local topographical Archer [20] and Lutz et al. [21] observed that a rise of 1°C setting and altitude variations on runoff contributions from in mean summer temperature over UIB has directly affected glacier melt, snow melt, and monsoon precipitation were the glacier melt and resulted in an increase of 17% in also evaluated. summer runoff for the river Shyok (basin area 65.025 km2) and a 16% increase for the river Hunza (basin area 2. Description of Study Area 13.925 km2), respectively. (e mean temperature in the UIB has increased over the last century; however, long-term (e Indus river basin is one of the world’s largest trans- persistent trends (>100 years) have not been detected boundary river basins with a total drainage area of about [15, 16]. Also, the statistically significant (p < 0:05) increases 1.08 ×106 km2 [27, 28]. (e UIB contributes to half of the in winter maximum temperature of 0.27, 0.55, and 0.51°C surface water disposal in Pakistan depending upon the per decade were observed at Gilgit, Skardu, and Dir in the melted water resources from Hindukush-Karakoram-Hi- UIB. (e climate change impacts are projected in a semiarid malayan (HKH) region. (e URB is located within the climate for the upper Indus basin rises of annual mean terrestrial ranges of 33° 40ʹ to 37° 12ʹ N and 70° 30ʹ to 77°, 30ʹ temperature up to 4.8°C and 18% increase in annual pre- E, in the mountainous ranges of Hindu-Kush, Karakoram, st cipitation by the end of the 21 century [22]. (ese findings Himalaya, and Tibetan Plateau [12, 17]. (ese ranges jointly indicated that warming is more pronounced in the Astore host 11,000 glaciers [29], which make it one of the world’s (5.4°C) and Gilgit (5.4°C) river basins compared to the most glaciated areas, with roughly 22,000 km2 of glacier Skardu (4.9°C) river basin in the summer season. Projected surface area [30]. (e altitude in the UIRB varies from 200 m changes in precipitation in the Hunza (+19%) and Gilgit to 8500 m.a.s.l with an average elevation of 3750 m a.s.l., (+21%) river basins are quite similar but changes in the covering a catchment area of 286,000 km2. (e research area Astore (113%) river basin are comparatively large. More- is considered as the prime source of fresh water for Pakistan over, long-term precipitation and temperature series in the and plays a vibrant role in the sustainable economic de- UIB exhibited a complex season-dependent spatial corre- velopment of the country.