Doctoral Dissertation Research: Creation and implementation of an early warning system for sand dune remobilization

全球大约三分之一的人口生活在干旱地区，在现代气候变化的影响下，干旱的持续时间和强度都在增加。干旱条件与沙丘再活化有关，即沙丘场从稳定到活跃的转变。重新动员可能对生活在干旱地区的人产生不利影响，包括对基础设施、农业和人类健康的影响。迄今为止，在全球各地的几项研究中已经注意到重新动员及其对周围社区的影响。虽然有沙丘再动员的研究，但大多集中在沙丘运动开始后的沙丘场。但是，如果能够在早期阶段发现沙丘的重新动员，就可以使社区参与主动的沙丘管理战略，而不是今天许多地方使用的被动方法。本博士论文项目研究沙丘再动员，为沙丘再动员预警系统提供信息。首先，进行了古气候-沙丘相互作用的研究，以确定现代再动员所需的气候。沙丘的形成、活动和稳定通常与气候变化有关，因此确定过去气候对沙丘的影响可以为未来的气候-沙丘相互作用提供信息。其次，在预测干旱条件增加将导致植被减少的情况下，建立了历史气候、干旱和植被变化之间的联系。植被是一种景观稳定器，因此随着时间的推移跟踪植被损失可以为即将重新动员的沙丘区提供早期预警。最后，沙丘颜色被认为是沙粒涂层存在的代表，沙粒涂层由铁和粘土组成，不仅作为景观稳定剂，而且还表现出可以通过遥感图像观察到的橙红色。研究调查将结合一套方法，包括古环境分析、遥感和扫描电子显微镜，这些方法尚未一起用于沙丘的再移动研究。研究成果和结果将为干旱地区沙丘恢复的早期预警系统提供信息。该奖项反映了美国国家科学基金会的法定使命，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。

Approximately one-third of the global population lives in arid regions, where drought has been increasing in duration and intensity under modern climate change. Drought conditions have been connected to dune remobilization, which is the transition of a dune field from stable to active. Remobilization can have detrimental effects on those living in arid lands, including impacts on infrastructure, agriculture, and human health. To date, remobilization and its impact on surrounding communities has been noted in several studies from around the globe. While studies on dune remobilization exist, they often focus on dune fields after movement has begun. However, if remobilization can be detected in its early stages, it allows communities to engage in proactive dune management strategies rather than the reactive approaches being used in many places today. This doctoral dissertation project investigates sand dune remobilization to inform an early warning system for remobilization. First, a study of paleoclimate-dune interactions is undertaken to determine the climate required for modern remobilization. Sand dune formation, activity, and stabilization have often been correlated with changes in climate, so determining the climatic impact on sand dunes from the past can inform climate-dune interactions in the future. Second, connections between historical climate, drought, and vegetation change are established under the prediction that increased drought conditions will reduce vegetation. Vegetation is a landscape stabilizer, so tracking vegetation loss over time can provide an early warning of a soon-to-be remobilizing dune field. Lastly, dune color is presented as a proxy for the presence of sand grain coatings, which are comprised of iron and clay and act not only as a landscape stabilizer but also exhibit an orange-red color that can be observed using remotely sensed imagery. Research investigations will combine a suite of methods, including paleoenvironmental analyses, remote sensing, and scanning electron microscopy that have not yet been used together for dune remobilization studies. Research products and findings will inform an early warning system for dune remobilization in arid regions.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.