RAPID: Characterizing Inundation and Sediment Transport Associated with Hurricane Michael: A Modern Analog for Paleo-Hurricane Reconstructions

RAPID：描述与迈克尔飓风相关的洪水和沉积物输送：古飓风重建的现代模拟

• 批准号: 1902463
• 负责人: Jeffrey Donnelly
• 金额: $ 5.13万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-11-15 至 2019-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1902463&HistoricalAwards=false
• 关键词: RAPID; Characterizing; Inundation; Sediment; Transport

Current efforts to understand the driving mechanisms responsible for modulating hurricane activity are significantly hampered by a short instrumental record of hurricane occurrence. Proxy records based on overwash layers deposited in coastal ponds and marshes provide a means of extending our knowledge of hurricane strikes back thousands of years. These paleo-records allow us to elucidate millennial and centennial scale patterns in hurricane activity and explore the mechanisms that drive changes in hurricane activity. Several of these reconstructions have been developed from the Panhandle of Florida and have extended our knowledge of hurricane activity in the area back more than 4000 years. However, well documented modern analogs are needed to help interpret the long term records. The landfall of Hurricane Michael on the panhandle of Florida in October 2018 provided an opportunity to investigate the character of overwash deposits associated with a category 4 strike. This research will examine sedimentological and landscape changes at three coastal sinkhole ponds on Bald Point, Florida, a location that is about 100 km from the center of where Hurricane Michael came ashore. The work will use elevation data and material from new sediment cores, taken from the ponds, and compare this information to results from longer term sedimentological records of previous studies from the same ponds. Results of this research will help constrain the character of prehistoric events that left deposits in the region over the past several millennia. Broader impacts of the work include increasing knowledge for use by federal disaster agencies, insurance companies, coastal managers, and communities about the probability and timing of major storm strikes on the Florida panhandle which should assist in better land and disaster planning. Impacts also include graduate student training and public outreach via lectures and conversations with community leaders. The latter outreach has strong potential for project media coverage.There is presently an insufficient understanding of what drives variability of hurricane activity on multidecadal and longer timescales due to the limited, in time and space, instrumental record of these strong storm events. Geologic proxies such as overwash layers preserved in coastal depositional settings provide an essential tool for examining hurricane variability in prehistory. This research involves the collection of drone-based aerial data and land surveys to examine geomorphic and elevation changes resulting from the storm and its storm surge. It also involves the collection of sediment cores on Bald Point on the Florida panhandle within 100 km of Mexico Beach where the eye of Hurricane Michael came ashore in October of 2018. Sediment sampling and surveys will be carried out at three coastal sinkhole ponds that have been previously studied: Little Tucker, Mullet, and Shotgun. Data collected in this study will be compared with the baseline data from these three sites, some of which includes LIDAR (LIght Detecting and Ranging) aircraft elevation surveys taken in 2010. Hurricane Michael sediment cores will be taken and samples will be examined for grain size, event-bed deposition, and clast composition. They will also be examined for the tests of microfossils, like foraminifera, ripped from the seabed. The latter data will provide insights into the extent and force of seabed wave/tide erosion and marine sediment transport during the storm. Questions to be addressed include: storm intensity and how that is recorded in the geological record and how close a storm needs to come to a site to result in event-bed deposition. Studies of modern analogs, such as the deposits left behind by Hurricane Michael, are essential for being able to correctly interpret the sediment record at this and other localities . It will also provide long-term reconstruction of strong storm events in the area and findings and protocols that may be applicable more widely. By characterizing the level of inundation and degree of sediment transport to the three targeted study sites, the project will be able to better interpret the nature of strong hurricane/storm events deposited over the last 4 millennia on the Florida panhandle.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.

目前了解调节飓风活动的驱动机制的努力受到飓风发生的短暂仪器记录的严重阻碍。基于沿海池塘和沼泽中沉积的洪水层的代理记录提供了一种扩展我们对数千年前飓风袭击的了解的方法。这些古记录使我们能够阐明飓风活动的千年和百年规模模式，并探索驱动飓风活动变化的机制。其中一些重建项目是在佛罗里达州狭长地带开展的，使我们对该地区飓风活动的了解延伸至 4000 多年前。然而，需要有充分记录的现代类比来帮助解释长期记录。 2018 年 10 月，迈克尔飓风在佛罗里达州狭长地带登陆，为调查与 4 级罢工相关的过度冲积物的特征提供了机会。这项研究将调查佛罗里达州巴尔德波因特 (Bald Point) 三个沿海污水坑池塘的沉积学和景观变化，该地点距飓风迈克尔登陆中心约 100 公里。这项工作将使用从池塘采集的新沉积物岩心的高程数据和材料，并将这些信息与同一池塘先前研究的长期沉积学记录的结果进行比较。这项研究的结果将有助于限制过去几千年来在该地区留下沉积物的史前事件的特征。 这项工作的更广泛影响包括增加联邦灾害机构、保险公司、沿海管理人员和社区对佛罗里达狭长地带发生重大风暴袭击的概率和时间的了解，这将有助于更好的土地和灾害规划。影响还包括研究生培训以及通过讲座和与社区领袖对话进行的公众宣传。后者的外展在项目媒体报道方面具有强大的潜力。由于这些强风暴事件的时间和空间仪器记录有限，目前对驱动飓风活动在数十年和更长的时间尺度上发生变化的原因还没有足够的了解。沿海沉积环境中保存的地质代理（例如冲刷层）为研究史前飓风变化提供了重要工具。这项研究涉及收集基于无人机的航空数据和土地调查，以检查风暴及其风暴潮造成的地貌和海拔变化。它还涉及在距墨西哥海滩 100 公里范围内的佛罗里达狭长地带秃角 (Bald Point) 收集沉积物岩心，迈克尔飓风的风眼于 2018 年 10 月在此登陆。沉积物采样和调查将在三个沿海天坑池塘进行，这些池塘已被之前学习过：小塔克、鲻鱼和猎枪。本研究中收集的数据将与这三个地点的基线数据进行比较，其中一些数据包括 2010 年进行的 LIDAR（光探测和测距）飞机高程调查。将采集迈克尔飓风沉积物岩心并检查样品的颗粒尺寸、事件床沉积和碎屑成分。还将对它们进行微化石测试，例如从海底捞出的有孔虫。后者的数据将提供对风暴期间海底波浪/潮汐侵蚀和海洋沉积物输送的程度和力度的见解。要解决的问题包括：风暴强度以及如何将其记录在地质记录中，以及风暴需要距离某个地点多近才能导致事件床沉积。对现代类似物（例如迈克尔飓风留下的沉积物）的研究对于正确解释该地区和其他地点的沉积物记录至关重要。它还将提供该地区强风暴事件的长期重建以及可能更广泛适用的调查结果和协议。通过表征三个目标研究地点的淹没水平和沉积物输送程度，该项目将能够更好地解释过去 4 千年来佛罗里达狭长地带沉积的强飓风/风暴事件的性质。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。