Collaborative Research: Incorporating hillslope transport into laboratory landscape experiments

丘陵和山区地形有一种明显的倾向，组织成重复的山脊和山谷。这些地貌序列的间距决定了水系的密度和山脉的高度，它取决于河道中的平流输沙和山坡上的扩散输沙之间的竞争。尽管数值模型的结果很有希望，但目前还不清楚气候和构造如何调节山坡和通道过程在确定景观解剖方面的相对有效性。为了测试这些基本的景观特性的控制，本研究将扩散山坡运输到现有的实验室模型积极侵蚀景观。我们的物理实验将产生可再生的山坡运输通过沉积物掺入针冰景观表面，而渠道将通过洒水器的降水演变。由于实验将能够隔离和操纵山坡和通道过程的速率，我们将在广泛的气候和构造情景下记录地貌发展。此外，作为第一个物理实验，明确纳入山坡过程，这项研究将跟踪动态的地形调整，如山脊迁移和排水捕获，在一个系统中与地球的大部分？以前的数值和实验研究气候控制景观演变一般集中在如何降水驱动渠道流量和山谷切割。然而，气候也通过冰缘过程和植被的变化调节山坡上的沉积物产生和运输，深刻影响景观的地形组织。从我们的实验景观的结果将通知努力解码过去的气候信号的地形，以及预测未来气候变化对景观演变的影响。物理实验是推广和科学招募的有力工具，因为它们能够以实时和高度可访问的方式减少复杂的百万年规模的过程。这些资金还将用于建造一个专门为教学和推广而设计的实验性景观装置。除了支持一名博士生的教育外，这笔赠款还包括为当地社区学院的学生提供研究经验，并为本科生举办景观演变研讨会。

Hilly and mountainous terrain has a remarkable tendency to organize itself into repeating ridges and valleys. The spacing of these landform sequences, which sets the density of drainage networks and the height of mountains, depends on the competition between advective sediment transport in channels and diffusive sediment transport on hillslopes. Despite promising results from numerical models, it is unclear how climate and tectonics modulates the relative effectiveness of hillslope and channel processes in determining landscape dissection. To test controls on these fundamental landscape properties, this research will incorporate diffusive hillslope transport into an existing laboratory model for actively eroding landscapes. Our physical experiments will generate reproducible hillslope transport via sediment incorporation in needle ice on the landscape surface while channels will evolve through precipitation from sprinklers. Because the experiments will be able to isolate and manipulate rates of hillslope and channel processes, we will document landform development under a wide range of climatic and tectonic scenarios. Furthermore, as the first physical experiment to explicitly incorporate hillslope processes, this research will track the dynamics of landform adjustment, such as ridge migration and drainage capture, in a system with relevance to much of the Earth?s surface.Previous numerical and experimental studies of climate controls on landscape evolution generally focus on how precipitation drives channel discharge and valley incision. However, climate also modulates sediment production and transport on hillslopes through changes in periglacial processes and vegetation, profoundly affecting the topographic organization of landscapes. Results from our experimental landscape will inform efforts to decode past climate signals in topography as well as predict the effect of future climate change on landscape evolution. Physical experiments are a powerful tool for outreach and science recruitment because of their ability to reduce complex, million-year-scale processes in a real-time and highly accessible fashion. The funds will also provide for the construction of an experimental landscape apparatus designed explicitly for teaching and outreach. In addition to supporting the education of a PhD student, this grant includes research experience for students from local community colleges and provides for the development of a landscape evolution seminar for undergraduates.