In this study, we analyzed the hydrological and meteorological data from the Syr Darya River Basin during the period of 1930–2015 to investigate variations in river runoff and the impacts of climate change and human activities on river runoff. The Syr Darya River, which is supplied by snow and glacier meltwater upstream, is an important freshwater source for Central Asia, as nearly half of the population is concentrated in this area. River runoff in this arid region is sensitive to climate change and human activities. Therefore, estimation of the climatic and hydrological changes and the quantification of the impacts of climate change and human activities on river runoff are of great concern and important for regional water resources management. The long-term trends of hydrological time series from the selected 11 hydrological stations in the Syr Darya River Basin were examined by non-parametric methods, including the Pettitt change point test and Mann-Kendall trend tests. It was found that 8 out of 11 hydrological stations showed significant downward trends in river runoff. Change of river runoff variations occurred in the year around 1960. Moreover, during the study period (1930–2015), annual mean temperature, annual precipitation, and annual potential evapotranspiration in the river basin increased substantially. We employed hydrological sensitivity method to evaluate the impacts of climate change and human activities on river runoff based on precipitation and potential evapotranspiration. It was estimated that human activities accounted for over 82.6%–98.7% of the reduction in river runoff, mainly owing to water withdrawal for irrigation purpose. The observed variations in river runoff can subsequently lead to adverse ecological consequences from an ecological and regional water resources management perspective.

中文翻译：

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气候变化和人类活动下锡尔河流域径流的长期变化

在这项研究中，我们分析了锡尔河流域 1930-2015 年期间的水文和气象数据，以调查河流径流的变化以及气候变化和人类活动对河流径流的影响。上游由雪和冰川融水供应的锡尔河是中亚重要的淡水来源，近一半的人口集中在该地区。这个干旱地区的河流径流对气候变化和人类活动很敏感。因此，气候和水文变化的估算以及气候变化和人类活动对河流径流影响的量化对区域水资源管理具有重要意义和重要意义。通过非参数方法，包括 Pettitt 变点检验和 Mann-Kendall 趋势检验，对 Syr Darya 河流域选定的 11 个水文站的水文时间序列的长期趋势进行了检验。发现11个水文站中有8个河流径流呈显着下降趋势。河流径流变化的变化发生在1960年左右。此外，在研究期间（1930-2015年），流域年平均气温、年降水量和年潜在蒸散量显着增加。我们采用水文敏感性方法，基于降水和潜在蒸散量评估气候变化和人类活动对河流径流的影响。据估计，人类活动占82.6%~98%以上。河流径流减少 7%，主要是由于灌溉取水。从生态和区域水资源管理的角度来看，观察到的河流径流变化随后会导致不利的生态后果。