Collaborative Research: Modeling and monitoring of landscape evolution along a climate gradient: Kohala Peninsula, Hawaii

合作研究：沿气候梯度模拟和监测景观演化：夏威夷科哈拉半岛

• 批准号: 1024982
• 负责人: Joel Johnson
• 金额: $ 20.17万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1024982&HistoricalAwards=false
• 关键词: Collaborative; Research; Modeling; monitoring; landscape; Collaborative; Research; Modeling; monitoring; landscape

Climate, and more specifically rainfall, is amongst the most important forces that shape a landscape, yet quantifying the impacts of rainfall on landscape development remains a challenge. It is easy to see the differences between the topography in arid versus humid landscapes, but it is has proven difficult to quantify how physical processes such as soil development, surface and subsurface water flow, and hillslope and fluvial erosion, differ between these two environments. The Kohala Peninsula, on the northern tip of the Big Island of Hawaii, offers an excellent field environment to address this question. Across the approximately 20 km wide peninsula, rainfall rates very from upwards of 4,000 mm/year to less than 200 mm/year. Deeply incised gulches dominate the topography of the wet side of the peninsula, while on the dry side, shallow gulches disappear and reappear across the landscape. The wet side of the peninsula has developed deep soils and the process of weathering is so intense that a fingernail can scrape a groove in many rocks. In contrast, on the dry side, surface soils are often shallow and rocky and exposed rock surfaces are much less weathered. This project will quantify the differences in hydrologic and erosion processes on the contrasting sides on the peninsula using both field monitoring and numerical modeling. Two watersheds, one on the dry side and one on the wet side, will be equipped with devices to measure rainfall rates, water flow depths on both the hillslopes and in the gulches, soil moisture content, and erosion rates. These devices will operate continually throughout the duration of the project. Field surveys will provide detailed observations of the geometry of the gulches and the variables that control incision rates, such as sediment grain size, rock hardness, and degree of fracturing. These data will be incorporated into a numerical landscape evolution model. The model will be used to systematically explore feedbacks between key climatic controls and surface process responses over the time scales at which landscapes evolve. Field data will be used to both constrain physical processes in the model and inspire the specific modeling scenarios.This project will address a fundamental scientific question of how rainfall patterns actually influence the processes of weathering and erosion. Rainfall gradients are present across almost every mountain range on Earth and the findings from this study will have broad significance beyond the Hawaiian Islands. Knowledge of the detailed interactions among climate, hydrology, and erosion can be applied to landscapes across the planet. Furthermore, by quantifying links between landscape development and rainfall, the effects of potential climate change on landscape evolution can be predicted more effectively. This project will develop a number of numerical models that will be freely available for use throughout the scientific community, so that the findings from this study can be easily applied in other settings and to a wide range of scientific questions.

气候，更具体地说是降雨，是塑造景观的最重要力量之一，但量化降雨对景观发展的影响仍然是一个挑战。 很容易看到干旱景观与潮湿景观中的地形之间的差异，但是事实证明，很难量化这两个环境之间的物理过程，例如土壤发育，表面和地下水流以及山坡和河流侵蚀的方式。 位于夏威夷大岛北端的Kohala半岛提供了一个极好的现场环境来解决这个问题。 在大约20公里宽的半岛上，降雨率从4,000毫米/年到/年不到200毫米/年。 深切切开的峡谷占据了半岛湿侧的地形，而在干燥的侧面，浅湾消失了，并重新出现在整个景观上。 半岛的潮湿一面已经发展出深层土壤，风化过程非常强烈，以至于指甲可以在许多岩石中刮擦凹槽。 相反，在干燥的一面，表面土壤通常是浅的，岩石和裸露的岩石表面的风化要少得多。 该项目将使用现场监测和数值建模来量化半岛对比度的水文和侵蚀过程的差异。 两个分水岭，一个在干燥的一侧，一个在湿侧，将配备设备，以测量降雨速率，山坡上的水流深度，沟渠和沟渠，土壤水分含量和侵蚀率。 这些设备将在整个项目的整个过程中不断运行。 现场调查将对沟渠的几何形状以及控制切口速率的变量（例如沉积物晶粒尺寸，岩石硬度和破裂程度）提供详细的观察结果。 这些数据将纳入数值景观演化模型中。 该模型将用于系统地探索关键气候控制和表面过程响应之间的反馈，并在景观发展的时间范围内进行反馈。 现场数据将用于限制模型中的物理过程并激发特定的建模方案。本项目将解决一个基本的科学问题，即降雨模式如何实际影响风化和侵蚀过程。 地球上几乎每个山脉都存在降雨梯度，这项研究的发现将在夏威夷群岛以外具有广泛的意义。 可以将了解气候，水文学和侵蚀之间的详细相互作用的知识应用于整个地球的景观。 此外，通过量化景观发展与降雨之间的联系，可以更有效地预测潜在气候变化对景观进化的影响。 该项目将开发许多数值模型，这些模型将在整个科学界免费使用，以便可以轻松地将本研究的发现轻松应用于其他环境和广泛的科学问题。