Patterns of Precipitation and Their Control on Landscape Dynamics

在地球科学中，最持久的挑战之一是理解塑造我们周围景观的力量的平衡。直觉上，气候显然起了作用。人们只需要目睹湍急的河流，或者看到冰川前的岩石碎片幕。此外，从远处看云雾缭绕的山，很容易理解地形本身在天气中所起的作用。只是在最近几年，定量工具才被用于研究大气过程和侵蚀过程之间的相互作用。这个建议在一个最好的环境中解决了这个挑战的各个方面。华盛顿州的奥林匹克山脉。一个可操作的数值天气预报模式提供了一个独特的7年高分辨率输出档案。它是一种非常复杂的工具，可以详细诊断大气流动对地形的响应以及对降水模式的影响。七年涵盖了各种各样的天气条件，但这种模式非常持久。在过去的四年里，该小组已经运行了一个密集的降水测量网络，能够评估这种模式。这笔拨款的支持将为该网络增加自动化气象站，并在野外再维持三年。水文模型通常将这些降水模式转化为河流流量。它们的输出可以通过流量计来评估。在地质时间尺度上，这些河流排放的模式转化为地表侵蚀的模式，最终塑造了山脉本身。这项拟议研究的第二部分将结合对控制河流侵蚀和陆地滑动的最新理解，以及从气象分析中获得的对降水时空格局的理解。更广泛的影响。这项工作解决了一个高度跨学科的挑战，这是地球科学的未来。这项研究的目标是任何在山上徒步旅行并对这些东西是如何形成的感到好奇的人感兴趣的。拟议的工作也与滑坡危害评估有具体的相关性，研究小组定期与经济贫困地区的学童进行有关这项工作的交流。

One of the most enduring challenges in the Earth Sciences, existing their inceptions as fields of study, has been to understand the balance of forces acting to sculpt the landscape around us. Intuitively, it is clear that climate plays a role ? one simply has to witness a powerful river at high stage, or to see the debris curtain of rock laid out in front of a glacier. Moreover, seeing a cloud-draped mountain from afar, it is easy to understand that the role that topography itself plays in weather. It is only in recent years that quantitative tools have been brought to bear on studying the mutual interactions between atmospheric and erosional processes. This proposal tackles aspects of this challenge in one of the best settings available ? the Olympic Mountains of Washington State. A unique seven-year archive of high-resolution output from an operational numerical weather prediction model is available. It is a very sophisticated tool for diagnosing in detail the response of atmospheric flow to the topography and the consequences for the pattern of precipitation. Seven years covers a wide variety of synoptic conditions, but the pattern is remarkably persistent. For the last four years the group has operated a dense network of precipitation gauges able to evaluate this modeled pattern. Support from this grant will add automated weather stations to this network, and maintain it in the field for another three years. Hydrological models routinely convert these precipitation patterns into river discharge. Their output can be evaluated from stream flow gauges. On geologic time scales these patterns in river discharge translate into patterns of surface erosion that ultimately act to shape the mountain range itself. The second part of this proposed research will combine the latest understanding of what controls fluvial erosion and land-sliding with the understanding of the spatial and temporal patterns of precipitation gained from the meteorological analyses. Broader Impacts. This work tackles a highly interdisciplinary challenge, of the sort that is the future of the Earth Sciences. The goals of the research are of interest to anyone who has hiked in the mountains and been curious about how such things came to be. The proposed work also has concrete relevance for assessment of landslide hazards, and the research group regularly engages with school children in an economically-deprived area about this work.