An Exploration of the Role of Mountain River Sinuosity in Landscape Dynamics

我们最近发现，台风活动以一种可测量的方式记录在山体景观的形状中。我们发现台风来袭频率与基岩河流的曲折程度有很好的相关性，极端降雨和洪水流量的相对频率也是如此。这一观察指向了对景观动态的基本气候控制，我们打算在本项目中详细探讨这一点。我们的重点将是日本和台湾的山区河流，这两个地区的景观跨越了从台风为主的热带到温带中纬度的广泛气候范围，从而为研究气候影响提供了一个广泛的参数范围。我们将在示范地点检查这些河流的地貌，以收集河段弯曲度、跨海峡地貌、水文和基岩强度的数据库。在这些数据的帮助下，我们将确定基岩可蚀性、沉积物装甲和流量统计在弯曲度演变中的各自作用。与此同时，我们将致力于曲折增长和减少的范围尺度模型的理论发展。我们的最终目标是证明洪水变化性和河道流动性在山区景观演变中的重要性。该项目将有助于促进美国、英国、日本和台湾大学和研究机构的科学家和工程师之间的合作。它将支持一名研究生的参与。我们对台风引发的洪水影响的预期见解将对一系列学科的地球科学家以及那些关注热带气旋频繁袭击环境中的自然灾害和民防的人感兴趣。

We have recently discovered that typhoon activity is recorded in a measurable way in the shape of mountain landscapes. We have found that typhoon strike frequency correlates well with the sinuosity of bedrock rivers, as does the relative frequency of extreme rainfall and flood discharge. This observation points to a fundamental climatic control on landscape dynamics, which we intend to pursue in detail in this project. Our focus will be the mountain rivers of Japan and Taiwan, whose landscapes together span a broad climatic range from the typhoon-dominated tropics to the temperate mid-latitudes, thereby providing a broad parameter range for study of the climatic effects. We will examine the morphology of these rivers at exemplary locations to gather a database of reach sinuosity, cross-channel morphology, hydrology and bedrock strength. With the help of these data, we will establish the respective roles of bedrock erodibility, sediment armoring and discharge statistics on sinuosity evolution. At the same time we will pursue theoretical development of a reach-scale model of sinuosity growth and reduction. Our ultimate aim is demonstrate the importance of flood variability and channel mobility in the evolution of mountain landscapes.The project will help to foster collaboration among scientists and engineers at universities and research agencies in the US, UK, Japan and Taiwan. It will support the involvement of one graduate student. Our anticipated insights into the effects of typhoon-driven floods will be of interest both to geoscientists across a range of disciplines and to those concerned with natural hazards and civil defense in environments subject to frequent tropical cyclone strikes.Cofunded by the Office of International Science and Engineering, NSF.