EAPSI: Understanding the pre-conditioning effects of solar radiation and precipitation on post-wildfire erosion

美国各地的野火正在增加，而与火灾有关的危险并没有在火灾被扑灭后结束。被烧毁的土壤比普通的森林土壤更容易受到侵蚀，因此野火后的第一场雨可能会造成灾难性的侵蚀。为了预测哪里会发生最严重的侵蚀，我们必须了解不同的土壤在燃烧后是如何被侵蚀的。本研究将探讨景观干旱（降水和辐射的函数）是否可以作为火灾后侵蚀的预测因子。本研究将探讨干旱土壤在山区局部斑块上的发育是否会影响土壤的侵蚀力，以及干旱土壤的优先侵蚀是否会导致长期的山地不对称。该结果可以更好地预测野火后的侵蚀。这项研究将在澳大利亚墨尔本大学研究野火后侵蚀的全球专家加里·谢里丹博士的监督下进行。这项研究将利用遥感图像和地形数据来计算澳大利亚维多利亚州山脉的干旱指数。绘制干旱指数将有效地描绘出可能形成干旱土壤的地方。实地工作将包括测量最近被烧毁的地区的土壤性质，这些地区被绘制为干旱土壤，我们将与从非干旱地区获得的样品进行比较。在野外活动中，我们将通过测量水的入渗能力、土壤抗剪强度和土坑基岩以上土壤总深度来测试现场土壤水文特性。将进行数值模拟，以确定优先侵蚀如何影响频繁燃烧景观的长期地貌山坡演变。NSF EAPSI奖是与澳大利亚科学院合作资助的。

Wildfire is increasing across the United States, and the hazards associated with fire do not end once the fire is extinguished. Burned soils are more susceptible to erosion than regular forest soils, therefore the first rains after a wildfire can generate catastrophic erosion. To predict where the most severe erosion will occur, we must understand how different soils erode after they are burned. This research will explore if landscape aridity (a function of precipitation and radiation) can be used as a predictor of post-fire erosion. This study will investigate if arid soil development on local patches of a mountain range will influence soil erosivity and if the preferential erosion of arid soils leads to mountain asymmetry over long time periods. The results could lead to better predictions of post-wildfire erosion. This research will be conducted under the supervision of Dr. Gary Sheridan, a global expert on the study of post-wildfire erosion, at the University of Melbourne in Australia. This research will use remote sensing imagery and topographic data to calculate the aridity index across a mountain range in Victoria, Australia. Mapping of the aridity index will effectively delineate where arid soils are likely to form. Fieldwork will involve measurements of soil properties in recently burned areas that were mapped as arid soils, which we will compare with samples obtained from non-arid zones. During the field campaign, we will test in-situ soil hydrologic properties by measuring the water infiltration capacity, the soil shear strength, and the total soil depth above bedrock in soil pits. Numerical modeling will be performed to determine how preferential erosion will effect long-term geomorphic hillslope evolution of a frequently burned landscape. This NSF EAPSI award is funded in collaboration with the Australian Academy of Science.