Collaborative Research: On the Intensity and Size Relationship of Tropical Cyclones

热带气旋是最具破坏性的自然现象，每年都会造成巨大的人员伤亡和经济损失。它们的强度和大小是评估TC严重程度和潜在危害的两个最重要的矩阵，但它们之间的关系还没有得到很好的理解，预测具有挑战性。对TC强度-规模关系的进一步理解将有助于进一步改进TC强度和规模的业务预报。这些改进反过来将有助于沿海社区为最大的潜在损害做好准备，并导致拯救生命和尽量减少财产损失。该项目将培养两名博士。该项目由一名本科生和一名博士后组成，他们从事大气动力学、建模和数据科学领域的研究，并通过与一名本科生合作，根据从该项目中获得的知识，启动对TC强度和大小的实验预测，支持STEM教育。研究结果和实验预测将通过同行评议的出版物传达给科学界，通过课堂教学和课程开发传达给大学生，通过网站和twitter账户传达给公众。该项目是建立在以前NSF资助的EAGER项目中获得的知识和见解的基础上，该项目通过结合绝对角动量（AAM）和由于表面阻力导致的AAM损失，提出了TC表面风径向廓线的“有效绝对角动量”（eAAM）径向不变模型。本项目的主要目标是探索AAM径向损失和eAAM值对环境因子的依赖性，以便eAAM模型能够更好地解释观测到的TC强度-大小关系的复杂性和丰富多样性。本研究以三个以过程为基础的工作假设所证实的中心假设为指导。在此框架下，不同的eAAM值的结果取决于环境条件的AAM的向内径向损失的差异。通过6组A-B系列数值试验，研究了AAM和eAAM的径向向内损失率与环境条件的关系。所得到的环境依赖eAAM模型将通过要求使用观测到的大小信息的eAAM预测的TC风和使用观测到的风信息的eAAM预测的TC大小高度一致来验证（在观测不确定性范围内）该奖项反映了美国国家科学基金会的法定使命，并通过利用基金会的知识价值和更广泛的影响进行评估，被认为是值得支持的审查标准。

Tropical cyclones (TCs) are the most destructive natural phenomena, causing many casualties and enormous economic loss every year. Their intensity and size are the two most important matrics for assessing TC severity and potential hazards but their relation is not well understood and challenging to be predicted. The improved understanding of TC intensity-size relation will shed insights into how operational forecasts for TC intensity and size could be further improved. These improvements will in turn help coastal communities to prepare for the maximum potential damage and lead to saving lives and minimizing the losses of properties. This project will train two Ph.D. students and a postdoc in fields of atmospheric dynamics, modeling, and data science, and support STEM education by working with an undergraduate student to launch experimental forecasts for TC intensity and size based on the knowledge gained from the project. The research findings and experimental forecasts will be communicated to the science community via peer-reviewed publications, to college students via classroom teaching and curriculum development, and to general public via website and twitter accounts. This project is built on the knowledge and insights gained from a previously NSF-funded EAGER project, which put forward a radial invariant model of “effective absolute angular momentum” (eAAM) for radial profiles of TC surface winds by combining the absolute angular momentum (AAM) and the loss of AAM due to surface drags. The main goal of this project is to explore the dependencies of radial loss of AAM and eAAM values on environment factors so that the eAAM model would better explain the observed complexity and rich diversity of TC intensity-size relation. This research is guided by the central hypothesis substantiated by three process-based working hypotheses. Under this framework, different eAAM values result from differences in the inward radial loss of AAM that depends environment conditions. The central question of how the inward radial loss rate of AAM and eAAM are related to environment conditions is investigated through 6 sets of A-B series numerical experiments using the Cloud Model Version 1 (CM1) model for the A-series and cloud-permitting version of the Weather Research and Forecast (WRF) model for the B-series. The resultant environment-dependent eAAM model will be validated by requiring that both the eAAM-predicted TC winds using observed size information and the eAAM-predicted TC sizes using observed wind information are highly in agreement (within observation uncertainties) with their observational counterpartsThis 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.