Collaborative Research: Tropical Cyclone Variability in the Western North Pacific Over the Common Era

热带气旋，也被称为台风或飓风，是在温暖的热带海洋上形成的强烈风暴。它们会对建筑物造成破坏，甚至造成生命损失。西北太平洋是热带气旋最多的地区，平均每年有40个风暴。然而，记录热带气旋的仪器只存在了大约75年。该项目将获取多个地点的沉积记录，用于记录西北太平洋过去数千年的热带气旋活动。结果对于了解控制热带气旋频率和强度的气候因素将是重要的。更广泛的影响包括对本科生和研究生的支持，以及在美国和菲律宾的教育推广活动。保存在沿海沉积盆地中的粗粒风暴引起的沉积，是现场强烈热带气旋影响的特别有效的代用品。以前发表的工作和初步数据表明，沉积迅速积累的深海沿海洼地包含强烈热带气旋经过的高分辨率记录。然而，到目前为止，在西北太平洋还很少有这样的长期沉积记录。该项目将收集菲律宾、帕劳、关岛、楚克、波恩佩和西太平洋科斯雷等地的地震、多波束和沉积物岩心数据。收集的沉积物岩心将采用多种替代方法进行分析，其中包括粗颗粒和粒度分布测量、点火损失分析、X射线荧光扫描的射线照相和元素分析、沉积物岩石学、微化石和宏观化石分析以及计算机断层成像。现代沉积类比也将被分析。将使用基于短期同位素和使用贝叶斯统计框架的放射性碳测年的多代理方法确定岩心的年代。这些千年尺度的重建将提供一种延长数千年前热带气旋袭击的文献记录的手段，并允许：1)审查缺乏现代类似物的气候/热带气旋相互作用；2)产生更准确的重现率估计；3)评估风暴活动在亚千年时间尺度上的变化。这项工作的结果将提供西北太平洋热带气旋活动过去模式的基本数据，并提供对影响热带气旋频率、强度、轨迹和发展区域的气候因素的更广泛的洞察。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Tropical cyclones, also called typhoons or hurricanes, are intense storms that form over warm tropical oceans. They can cause damage to buildings and even loss of life. The western North Pacific is the location of the most tropical cyclones with an average of 40 storms per year. However, instruments that record tropical cyclones have only existed for about 75 years. This project will acquire sedimentary records across multiple sites that will be used to document tropical cyclone activity for the last several thousand years in the western North Pacific. Results will be important for understanding climate factors that control tropical cyclone frequency and intensity. Broader impacts include support for undergraduate and graduate students and educational outreach activities in the U.S. and Philippines.Coarse-grained storm-induced deposits, preserved in coastal sedimentary basins, are particularly effective proxies for intense tropical cyclone impacts at a site. Previously published work and preliminary data show that deep coastal depressions with rapidly accumulating sediments contain high-resolution records of the passage of intense tropical cyclones. However, few such long-term sedimentary records have been developed thus far in the western North Pacific. This project will collect seismic, multibeam, and sediment core data for sites across the Philippines, Palau, Guam, Chuuk, Pohnpei, and Kosrae in the western North Pacific. Collected sediment cores will be analyzed using a multi-proxy approach consisting of coarse fraction and grain-size distribution measurements, loss on ignition analysis, radiography and elemental analysis via X-ray fluorescence scanning, sediment petrography, microfossil and macrofossil analysis, and computed tomography. Modern sedimentary analogs will also be analyzed. Cores will be dated using a multi-proxy approach based on short-lived isotopes and radiocarbon ages using a Bayesian statistical framework. These millennial-scale reconstructions will provide a means of extending documentary records of tropical cyclone strikes back millennia and allow for i) the examination of climate/tropical cyclone interactions that lack modern analogs, ii) the generation of more accurate reoccurrence rate estimates, and iii) assessment of variations in storm activity on sub-millennial time scales. The results of this work will provide essential data on past patterns of tropical cyclone activity in the western North Pacific and offer broader insight into climate factors that modulate tropical cyclone frequency, intensity, track, and area of development.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.