更多的上游流量和下游流量:全球河流的变化形式和功能
Dongmei Feng1, Colin J Gleason2
1Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH, USA.
概括
全球河流的流量正在上游转移, 这影响了侵蚀,洪水风险和营养循环,特别是在较小的河流中,影响了全球29%的土地.
科学领域:
- 水文学
- 环境科学
- 地理空间分析
背景情况:
- 全球河流系统对生态系统和人类活动至关重要.
- 了解河流流动的最新变化对于水资源管理和生态健康至关重要.
- 之前的研究往往不足以捕捉河流网络的细粒度变化.
研究的目的:
- 从1984年到2018年对全球数百万条河流的每日流量进行测绘和评估.
- 识别河流变化的空间模式,特别是河头和河口之间的变化.
- 量化这些变化对侵蚀,洪水频率和营养动态的影响.
主要方法:
- 通过绘制大约290万条河流的每日流量,利用了"规模细节"的方法.
- 分析了1984年至2018年的流量数据,以检测显著的增加和减少.
- 评估了河流功率,百年洪水频率和季节性流动模式的变化.
主要成果:
- 河流出口的流量主要显著下降.
- 河源的流量增加的可能性是降低的1.7倍.
- 大约29%的全球陆地面积经历了上游的流量转移.
- 最小的河流显示出最明显的变化,包括侵蚀潜力增加5%和百年洪水频率增加42%.
结论:
- 最近的全球流量变化显示出一个显著的上游变化,改变了水文动态.
- 这些变化增加了侵蚀和洪水的风险,特别是在较小的河流系统中.
- "规模细节"绘制方法为水球变化提供了前所未有的洞察力,并可广泛用于未来的研究.
相关概念视频
Rapidly Varying Flow
51
Rapidly varying flow (RVF) in open channels is characterized by abrupt changes in flow depth over a short distance, with the rate of depth change relative to distance often approaching unity. These flows are inherently complex due to their transient and multi-dimensional nature, making exact analysis difficult. However, approximate solutions using simplified models provide valuable insights into their behavior.Key Features of Rapidly Varying FlowRVF is commonly observed in scenarios involving...
51
Gradually Varying Flow
34
Gradually varying flow (GVF) in open channels describes situations where water depth changes slowly along the channel due to factors like non-uniform bed slope, channel shape variations, or obstructions. This flow type occurs when the depth adjusts gradually to balance gravitational forces, shear forces, and energy requirements, resulting in a low rate of depth change.Characteristics of Gradually Varying FlowGVF is commonly observed in natural streams, rivers, and canals, where flow depth...
34
The Water Cycle
24.2K
The Earth’s hydrosphere includes all of the areas where the storage and movement of water occurs. Since water is the basis of all living processes, the cycling of water is extremely important to ecosystem dynamics.
24.2K
Global Climate Change
24.2K
Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.
24.2K
Typical Model Studies
340
Fluid mechanics model studies often utilize scaled-down systems to predict fluid behavior in full-scale environments, such as river flows, dam spillways, and structures interacting with open surfaces. Maintaining Froude number similarity in river models is crucial, as it replicates surface flow features like wave patterns and velocities.
340
What is an Ecosystem?
39.4K
Overview
39.4K


