近日，英国帝国理工学院Jonah S. McLeod团队分析了变暖世界中的河流间歇性。2024年3月26日出版的《地质学》发表了这项成果。

研究人员根据希腊Corinth裂谷的野外测量和全新世沉积物堆积速率，对影响近代到现代的河流间歇性的因素（河床中底砂被调动的频率）进行了新的限制。结果揭示了一些迄今为止记录的最低间歇性因素。研究表明，地中海河流可以在罕见的风暴事件中运输全年的沉积物泥沙。与历史洪水和降水数据耦合的间歇性计算表明，这些河流在约每4年一次的风暴期间输送一次底砂，与降雨量>50 mm/d和随后的洪水有关。这种水文气候是整个地中海地区的典型气候。

此外，气候模型预测欧洲各地的极端降水将会增加，超过沉积物输运阈值的事件频率将显著增加，到2100_CE，沉积物负荷可能增加一倍。在全球变暖的驱动下，随着可能存在间歇河流的干旱区面积的增加，敏感的景观正处于重大地貌变化的边缘。

据介绍，随着时间的推移，河流中的泥沙输送并不稳定。高度间歇的河流系统只在最重要的流量事件期间中输送底砂，且其对气候和降水模式的变化特别敏感。人类和景观很容易受到河流过程的影响，量化河流间歇性对于评估景观对气候变化导致的极端降水预测变化的响应至关重要。

附：英文原文

Title: Landscapes on the edge: River intermittency in a warming world

Author: Jonah S. McLeod, Alexander C. Whittaker, Rebecca E. Bell, Gary J. Hampson, Stephen E. Watkins, Sam A.S. Brooke, Nahin Rezwan, Joel Hook, Jesse R. Zondervan, Vamsi Ganti, Sinéad J. Lyster

Issue&Volume: 2024-03-26

Abstract: Sediment transport in rivers is not steady through time. Highly intermittent river systems, which only transport bedload during the most significant flow events, are particularly sensitive to changes in climate and precipitation patterns. People and landscapes can be vulnerable to fluvial processes, and quantifying river intermittency is critical for assessing landscape response to projected changes in precipitation extremes due to climate change. We generated new constraints on recent to modern fluvial intermittency factors—the frequency at which bedload is mobilized in a river—based on field measurements in the Corinth Rift, Greece, and Holocene sediment accumulation rates. Results reveal some of the lowest documented intermittency factors to date, showing Mediterranean rivers can transport an entire annual sediment load in a rare storm event. Coupling intermittency calculations with historical flood and precipitation data indicates these rivers transport bedload during one storm every ～4 yr, associated with rainfall >50 mm/d, and subsequent floods; this hydroclimate is typical across the Mediterranean region. Furthermore, climate models predict precipitation extremes will increase across Europe, and the frequency of events that surpass thresholds of sediment transport will increase significantly, potentially causing sediment loads to double by 2100_CE. As the area of arid land likely to host intermittent rivers also increases, sensitive landscapes are on the edge of significant geomorphic change, driven by global warming.

DOI: 10.1130/G52043.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G52043.1/637040/Landscapes-on-the-edge-River-intermittency-in-aredirectedFrom=fulltext