1960—2020年青藏高原东部主要河流的径流和泥沙变化特征

Streamflow and sediment change of major rivers in the Eastern Tibetan Plateau from 1960 to 2020

  • 摘要: 青藏高原作为"亚洲水塔", 对下游地区用水具有重要作用, 在气候变化和人类活动影响下, 河流的径流和输沙量已发生显著变化。选取青藏高原东部的黄河、长江、澜沧江、怒江和雅鲁藏布江五大河流源区, 利用站点实测数据和Pettitt突变点检验、线性回归等统计方法, 系统性地分析了1960—2020年间(近60 a)径流和泥沙的年际和季节性变化特征。主要结论为: ①近60 a来, 长江和怒江流域的年径流显著上升, 其余流域变化不显著, 径流变化存在较强的空间变异性, 在2006年左右存在突变点, 大部分站点的年径流在此后的十几年中均呈上升趋势; 年输沙量方面, 长江流域呈不显著上升, 黄河、澜沧江、雅鲁藏布江流域均呈不显著下降, 年际变化趋势与径流变化总体一致, 但变异性更大。②对于60 a尺度的季节径流, 上游站点冬、春季径流均呈增加趋势, 所有站点夏、秋季径流的变化趋势与年径流总体一致, 且夏季径流在空间分布上存在"北增南减"的特征。③澜沧江下游的水电梯级开发已经对下游天然径流过程产生干扰, 主要表现为径流年内分布的突变, 季节差异显著减小, 趋于均匀化。以上结论深化了对青藏高原径流和泥沙变化特征的认识, 可为开展径流趋势预估和水资源规划等提供科学参考。

     

    Abstract: Being recognized as the "Asian Water Tower", the Tibetan Plateau (TP) plays a pivotal role in regulating downstream water resources. However, significant alterations in runoff and sediment transport have been witnessed within its headwaters region, primarily due to the combined impacts of climate change and human activities. This study focuses on five major river basins in the Eastern TP, including the Yellow River, Yangtze River, Lancang River, Nujiang River, and Yarlung Zangbo River. A comprehensive analysis of the annual and seasonal variations in streamflow and sediment data from 1960 to 2020 (recent 6 decades) was conducted, utilizing extensive hydrological station measurements and various statistical methods, including the Pettitt change-point test and linear regression algorithm. Key conclusions include: ① Over the past six decades, the annual runoff in the Yangtze River and Nujiang River basins exhibited a significant upward trend, while changes in other basins remained less pronounced, with considerable spatial variability in runoff alterations. A majority of stations experienced an abrupt shift in annual runoff around 2006, followed by a sustained increase in the subsequent decade. As for the annual sediment transport, the Yangtze River basin showed an insignificant increase, while the Yellow River, Lancang River, and Yarlung Zangbo River basins all exhibited insignificant decreases. The variation trends was overall consistent with annual runoff, but with greater uncertainty. ② In terms of seasonality in the past six decades, the winter and spring runoff in upstream stations displayed a consistent rising trend across all basins, while the variation in summer and autumn runoff mirrored that of annual runoff, and the summer runoff demonstrated a spatial pattern, characterized by a distinct "northward increase, southward decrease" trend. ③ The development of water resources in the Lancang River basin has disrupted the natural runoff patterns downstream, notably manifesting as a sudden shift in the annual distribution of runoff, with reduction in seasonal variation. These findings enhance our understanding of streamflow and sediment changes in the Tibetan Plateau, offering valuable insights for predicting runoff trends and informing water resource management decisions.

     

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