Microfossil-based Approach to Estimate Hurricane Intensity from the Sedimentary Record

从沉积记录中估计飓风强度的微化石方法伍兹霍尔海洋研究所杰夫·唐纳利迄今为止，我们对飓风活动如何随时间变化以及未来如何变化的理解受到短期仪器和历史记录的阻碍。飓风在海岸沉积物中留下的沉积物为延长这一记录提供了一种手段。与飓风有关的风暴潮和海浪经常在盐沼和沿海池塘中沉积沙子。经过数百年到数千年的时间，飓风引起的沉积物沉积下来，随后被盐沼泥炭覆盖，形成了一种类似条形码的沙和泥沉积物，可以深入了解飓风的频率。然而，我们对过去这些风暴的强度知之甚少。在飓风期间，沙粒的厚度和沙粒的大小经常被用来估计飓风的强度，但这种方法是不完善的，因为飓风沉积物的大小和厚度可能在很大程度上由可用于运输的沉积物的数量控制。我们计划使用一种生活在所有海洋环境中被称为有孔虫的小生物来确定过去飓风沉积在新英格兰盐沼的沉积物来自哪里。这些生物是独特的，因为它们生活在离岸的一定深度范围内，所以在过去的飓风沉积物中找到它们将有助于我们确定海洋中沙子被挖掘的深度。考虑到更强烈的飓风导致更高的海浪，能够从更大的水深挖掘沉积物，在飓风诱发的沉积物中发现的更深的水有孔虫组合将预示着更强烈的风暴。为了验证我们的假设，我们将使用新英格兰南部飓风登陆的历史记录来确定来自不同水深、沉积在盐沼中的有孔虫是否反映了已知的飓风强度。一旦这种方法得到验证，我们就可以用它来估计几千年前沙层中有孔虫的飓风强度。飓风强度随时间的变化将提供重要的基线信息，有助于阐明气候对飓风强度的控制。这项工作的结果将对沿海资源管理者、减灾管理者和政策制定者有用，并将使这些群体能够就适当的管理实践和监管战略作出明智的决定。其他利益相关者（海岸带管理者、栖息地恢复团体、土地管理者、与风险管理有关的商业利益集团、沿海财产所有者和沿海科学家）将从这个项目的成果中受益。

MICROFOSSIL-BASED APPROACH TO ESTIMATE HURRICANE INTENSITY FROM THE SEDIMENTARY RECORD Jeff Donnelly,Woods Hole Oceanographic InstitutionTo date our understanding of how hurricane activity has changed over time and how it may change in the future is hampered by the short instrumental and historical record. Sand deposits left behind by hurricanes in coastal sediments provide a means of extending this record. Storm surge and waves associated with hurricanes often deposit sand in salt marshes and coastal ponds. Over hundreds to thousands of years hurricane-induced deposits are laid down and subsequently covered by salt marsh peat creating a barcode-like deposit of sand and mud that provides insight into hurricane frequency. However, we know little regarding the intensity of these past storms. The thickness of the sand deposit and size of sand grains transported during the hurricane has often been used to estimate how intense the hurricane was, but this method is imperfect because sand size and thickness of the hurricane deposits may be largely controlled by the amount of sediment available for transport. We plan to use a small organism called foraminifera that live in all marine environments, to determine where sediment deposited in New England salt marshes by past hurricanes is coming from. These organisms are unique because they live in certain depth ranges offshore, so finding them in past hurricane deposits will help us determine from how deep in the ocean the sand has been excavated. Given more intense hurricanes result in higher waves capable of excavating sediment from greater water depths, deeper water foraminifera assemblages found in hurricane-induced deposits will be indicative of a more intense storm. To test our hypothesis we will use the historic record of hurricane landfalls in southern New England to determine if foraminifera from different water depths, deposited within salt marshes, reflect known hurricane intensities. Once this method is tested we can use it to estimate hurricane intensity from foraminifera in sand layers going back thousands of years. The variation in hurricane intensity over time will provide important baseline information that will help elucidate the climatic controls on hurricane intensity. Results from this work will be useful to coastal resource managers, disaster mitigation managers, and policy makers and will enable these groups to make informed decisions regarding appropriate management practices and regulatory strategies. Other stakeholders (coastal zone managers; habitat restoration groups; land managers; business interests concerned with managing risk; coastal property owners and coastal scientists) will benefit from the results of this project.