Collaborative Research: The Role of the North Atlantic Oscillation (NAO) in Modulating Major Hurricane Activity in the U.S. on Interannual to Millennial Timescales

20世纪的记录表明，北美洲海湾和大西洋海岸线沿岸的飓风活动有相当大的变化。在墨西哥湾沿岸经历了十年的强烈飓风之后，东海岸又经历了十年的严重飓风。初步研究表明，这些周期与副热带大西洋高压单体(百慕大高压)的位置和强度有关，可能受北大西洋涛动(NAO)强度的控制。为了探索这些关系的动态，有必要考虑20世纪之前的过去飓风活动的记录。这项研究项目将研究百慕大高压和北大西洋涛动在调节美国沿海主要飓风活动方面的作用，时间尺度从年际到千年不等。大西洋沿岸和墨西哥湾沿岸的湖泊和沼泽将被取芯，这些海岸沉积物中保存的漫溢沙沉积将被研究，以产生过去飓风活动的替代记录。这些地质记录和来自历史文献的证据将利用地理信息系统和统计与现代仪器记录进行核对。过去的气候模式将从测量的和替代的指数中推断出来。该项目的目标是更好地了解与沿海飓风活动变化有关的气候模式，并改进对灾难性事件重现期的估计。将使用地理信息系统将不同的历史档案整理成电子文档。统计模型将被用来区分当地和区域的活动期和非活动期。将采用概率框架来捕捉数据中不同程度的不确定性。强飓风具有巨大的社会影响。大风、暴雨和风暴潮共同造成了对生命和财产的灾难性威胁。沿海人口的增长速度快于一般人口的增长速度，因此与强飓风相关的问题不断加剧。仔细检查通过该项目从科德角和墨西哥湾沿岸收集的历史文件和新的地质证据，将提供有关遥远过去飓风规律性的宝贵线索。仔细研究这些记录将对气候变异性和飓风频率之间的关系产生新的认识，这将使人们更好地了解美国和附近国家未来飓风灾难的威胁。

Records from the 20th century indicate considerable variations in coastal hurricane activity along the Gulf and Atlantic coastlines of North America. A decade of strong hurricanes on the Gulf coast is followed by a decade of severe hurricanes on the East coast. Preliminary research suggests that these cycles are related to the location and strength of the subtropical Atlantic high-pressure cell (Bermuda High), perhaps controlled by the strength of the North Atlantic Oscillation (NAO). To explore the dynamics of these relationships, it is necessary to consider records of past hurricane activity that predate the 20th century. This research project will examine the role of the Bermuda High and the North Atlantic Oscillation in modulating major U.S. coastal hurricane activity on time scales ranging from the inter-annual to the millennial. Lakes and marshes along the Atlantic coast and Gulf of Mexico coast will be cored, and the overwash sand deposits preserved in these coastal sediments will be studied to produce proxy records of past hurricane activity. These geological records and evidence from historical documents will be collated with the modern instrumental records using geographic information systems (GIS) and statistics. Past climate patterns will be inferred from measured and proxy indices. The objectives of this project are to better understand climate patterns associated with variations in coastal hurricane activity and to improve return-period estimates of catastrophic events. GIS will be used to collate the disparate historical archives into an electronic document. Statistical models will be used to distinguish periods of activity from inactivity locally and regionally. A probabilistic framework will be adopted to capture the varying levels of uncertainty in the data.Strong hurricanes have enormous societal impact. High winds, heavy rain, and storm surge combine to create a catastrophic threat to life and property. Coastal populations are growing faster than the population at large, thereby continually accentuating problem associated with strong hurricanes. Careful examination of historical documents and fresh geological evidence gathered from Cape Cod and the Gulf coast through this project will provide valuable clues about the regularity of hurricanes in the distant past. A careful study of these records will result in new knowledge about the relationship between climate variability and hurricane frequency, which will lead to a better understanding of the future threat of a hurricane disaster in the United States and nearby nations.