Collaborative Research: Characterizing controls on postfire steepland ravel - when does bioturbation go too far for diffusive models?

合作研究：表征对火后陡峭地拉尔的控制——生物扰动何时对扩散模型来说太过分了？

• 批准号: 2123220
• 负责人: Danica Roth
• 金额: $ 31.69万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-15 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2123220&HistoricalAwards=false
• 关键词: Collaborative; Research; Characterizing; controls; postfire

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).After a wildfire, soils on hillsides can be destabilized and subject to elevated risk of erosion. One way this erosion occurs is through a process known as dry ravel, in which the incineration of vegetation or disturbance by animals causes sediment particles to bounce, roll, and slide down the hillslope. In many steep landscapes, ravel is the primary form of erosion after fires and can supply material to post-fire hazards like debris flows. Post-fire erosion and hazard prediction models are urgently needed to inform responses to today’s changing wildfire regime, but they are currently hindered by the inability of commonly used sediment transport laws to account for ravel processes. This project will advance understanding of ravel erosion processes by directly measuring sediment movement on hillslopes that were recently burned by wildfires in California. The resulting process knowledge will enable better modeling of erosion and hazards in response to disturbances like wildfire, as well as better estimates of long-term erosion due to predicted changes in wildfire conditions. The principal investigators will also collaborate with local educators to develop a new outreach program and materials to provide authentic field research experiences to underprivileged K-12 students from groups historically underrepresented in STEM (science, technology, engineering, and mathematics), while shifting perceptions around outdoor experiences and geoscience careers.This study will use a novel combination of short-lived radionuclide analysis, high-resolution topographic data and physical measurements to calibrate and conduct the first field test of a convolutional sediment flux model on natural sediment transport. This work will test the hypothesis that, under key conditions in newly burned steeplands, disturbance by burrowing animals can entrain sediment fluxes characterized by heavy-tailed particle travel distance distributions, thereby escaping representation by diffusive, continuum-based models. This study will 1) pioneer a new methodology for inferring particle histories from ravel deposits; 2) document statistics on natural particle entrainment rates, travel distances and fluxes to investigate their functional relationships with controlling physical variables that evolve over time; 3) demonstrate the utility and identify use-case scenarios for nonlocal sediment transport models; and 4) provide insight on how connectivity between geomorphic and biotic processes informs dynamic responses.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该奖项全部或部分由2021年美国救援计划法案（公法117-2）资助。野火过后，山坡上的土壤可能会不稳定，并受到侵蚀风险的增加。这种侵蚀发生的一种方式是通过一个被称为干散的过程，在这个过程中，植被的焚烧或动物的干扰导致沉积物颗粒反弹，滚动和滑下山坡。在许多陡峭的景观中，碎石是火灾后侵蚀的主要形式，可以为泥石流等火灾后的危险提供物质。火灾后的侵蚀和灾害预测模型是迫切需要的，以告知今天不断变化的野火制度的反应，但他们目前受到阻碍的常用沉积物输运法无法解释的ravel过程。该项目将通过直接测量最近在加州被野火烧毁的山坡上的沉积物运动来促进对砾石侵蚀过程的理解。由此产生的过程知识将能够更好地模拟侵蚀和灾害，以应对野火等干扰，以及更好地估计由于野火条件的预测变化而造成的长期侵蚀。主要研究人员还将与当地教育工作者合作，开发新的外展计划和材料，为来自STEM历史上代表性不足的群体的贫困K-12学生提供真实的实地研究经验。（科学，技术，工程和数学），同时改变对户外体验和地球科学职业的看法。这项研究将使用一种新的组合，高分辨率地形数据和物理测量，以校准和进行关于自然沉积物输运的卷积沉积物通量模型的第一次实地测试。这项工作将测试的假设，在新烧的陡坡的关键条件下，由穴居动物的干扰可以夹带沉积物通量的特点是重尾颗粒的行程距离分布，从而逃避代表扩散，连续模型。这项研究将1）开创一种新的方法来推断颗粒的历史，从松散的沉积物; 2）文件的自然颗粒夹带率，旅行距离和通量的统计数据，以调查其功能与控制物理变量的关系，随着时间的推移演变; 3）演示的效用，并确定用例场景的非本地沉积物输运模型;以及4）提供地貌和生物过程之间的连接如何通知动态响应的见解。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。