CAREER: Understanding the Variability, Predictability and Changes of Tropical Cyclone Genesis Frequency in the North Atlantic: From Basin to Sub-basin Scales

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公法117-2)。北大西洋(NA)热带气旋(TCS)在我们的东海岸造成毁灭性的生命和财产损失。由于TC在观测中的数量很少，我们对TC成因变化背后的原因的了解仍然有限。这一局限性导致我们有时无法合理地预测盆地范围内的季节性TC生成频率，并导致在次流域尺度上预测季节性TC生成频率的持续挑战。因此，对TC活动有更好的理解和更好的预测是有益于社会的。本项目利用前所未有的大量高分辨率模式模拟来探索北美热带气旋的成因。这些模拟极大地扩展了数据稀疏区的输入，改善了TC的发生率，使我们能够检验控制盆地范围和子流域TC发生频率的基本过程。该项目的结果将有助于克服热带气旋路径和登陆的季节性预报方面的困难，因为加强了关于首选的气旋路径和气旋成因位置之间的关系的信息。这项研究将与教育、培训和扩大大气、海洋和气候科学中代表性不足群体的学生参与的活动相结合，并通过公共宣传向更广泛的社区提供信息。该项目的目的是提高对不同气候下北美地区全流域和子流域热带气旋发生频率的可变性、可预测性和变化的认识。研究的目的是：(1)描述由海表面温度(SSTs)驱动的热带气旋发生频率的强迫变率，以及由于大气的混沌性质而产生的内部变率，(2)评估这两种变率的物理机制，并确定它们对季节TC发生频率的可预测性的影响，(3)量化自20世纪70年代以来全球变暖对TC发生频率的气候学和趋势的影响，以及(4)探索SST变暖与温室气体的大规模增加如何影响TC发生频率，并评估气候变暖时TC发生频率的概率变化。这些目标将通过对一组非常大的长期、高分辨率模拟的动态诊断和统计分析来实现，这些模拟准确地再现了观测到的热带气旋特征。该项目将支持开发一门跨学科课程，以激发本科生对大气、海洋和气候科学的兴趣。它将为博士生提供培训，并为HBCU和北卡罗来纳大学教堂山分校的未被充分代表的本科生提供实践研究项目。这一奖项反映了NSF的法定使命，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。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).North Atlantic (NA) tropical cyclones (TCs) cause devastating losses of life and property along our Eastern Seaboard. Owing to the small number of TCs in observations, our knowledge of the reasons behind the variations in TC genesis remains limited. This limitation has resulted in our failure, at times, to reasonably forecast seasonal basin-wide TC genesis frequency and in continuing challenges to predict seasonal TC genesis frequency on sub-basin scales. As such, having an improved understanding and better predictions of TC activity is societally beneficial. This project utilizes an unprecedentedly large number of high-resolution model simulations to explore NA TC genesis. These simulations greatly expand the input in data-sparse regions and improve TC incidence, allowing us to examine the fundamental processes that govern both basin-wide and sub-basin TC genesis frequency. The project results will help overcome difficulties in seasonal forecasts of TC tracks and landfall, given the enhanced information regarding the relation between preferred TC tracks and TC genesis location. The research will be integrated with activities to educate, train, and broaden the participation of students from underrepresented groups in Atmosphere, Ocean and Climate Sciences as well as to inform the broader community through public outreach. The project aims to advance the knowledge of the variability, predictability, and changes of both basin-wide and sub-basin TC genesis frequency over NA under different climates. The research objectives are to: (1) characterize the forced variability in TC genesis frequency that is driven by sea surface temperatures (SSTs) and the internal variability that arises due to the chaotic nature of the atmosphere, (2) assess the physical mechanisms underlying these two types of variability, and determine their impacts on the predictability of seasonal TC genesis frequency, (3) quantify the effects of global warming on the climatology of and trend in TC genesis frequency since the 1970s, and (4) explore how SST warming combined with a sizable greenhouse gas increase affects TC genesis frequency and evaluate the probabilistic changes in TC genesis frequency in warmer climates. These objectives will be achieved via dynamical diagnosis and statistical analysis of a very large ensemble of long-term, high-resolution simulations that accurately reproduce observed TC characteristics. This project will support the development of an interdisciplinary course to stimulate the interest of undergraduates in Atmosphere, Ocean and Climate Sciences. It will provide training for doctoral students, and hands-on research projects for underrepresented undergraduates from HBCUs and UNC Chapel Hill. The results will also be integrated into local high-school curriculum.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.