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。北太平洋西部是热带气旋最多的地区，平均每年有40场风暴。然而，记录热带气旋的仪器只存在了大约75年。该项目将获得多个地点的沉积记录，这些记录将用于记录北太平洋西部过去几千年的热带气旋活动。研究结果将对理解控制热带气旋频率和强度的气候因子具有重要意义。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度风暴诱发沉积物是一个地点强烈热带气旋影响的特别有效的代用物。先前发表的工作和初步数据表明，沉积物迅速积聚的深海岸洼地包含强烈热带气旋通过的高分辨率记录。然而，迄今为止，在北太平洋西部很少有这样的长期沉积记录。该项目将在北太平洋西部的菲律宾、帕劳、关岛、楚克、波纳佩和科斯雷等地收集地震、多波束和沉积物岩心数据。收集到的沉积物岩心将使用多代理方法进行分析，包括粗馏分和粒度分布测量、着火损失分析、x射线成像和x射线荧光扫描元素分析、沉积物岩石学、微化石和宏观化石分析以及计算机断层扫描。现代沉积类似物也将进行分析。将使用基于短寿命同位素和使用贝叶斯统计框架的放射性碳年龄的多代理方法来确定岩心的年代。这些千年尺度的重建将提供一种延长千年前热带气旋袭击的文献记录的手段，并允许i)检查缺乏现代类似物的气候/热带气旋相互作用，ii)生成更准确的重现率估计，以及iii)评估亚千年时间尺度上风暴活动的变化。这项工作的结果将提供北太平洋西部过去热带气旋活动模式的基本数据，并对调节热带气旋频率、强度、路径和发展区域的气候因素提供更广泛的见解。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。

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.