Examining the Rainfall Distribution and Asymmetries during the Landfalling Process of Tropical Cyclones

暴雨引起的内陆淡水洪水是登陆的飓风或热带气旋（tc）造成的最致命和最昂贵的灾害之一。相对于对TC路径的认识和预测取得了很大进展，对TC强度变化的研究进展不大，TC降雨的定量预报仍然是一个具有挑战性的问题，而且进展甚微。本项目旨在通过关注热带气旋登陆时与大气环境的相互作用，提高对热带气旋降雨分布的认识，并改进热带气旋登陆时的降水定量预报。首席研究员将促进一名研究生的参与，特别是考虑到妇女和代表性不足的少数民族学生在开展这项研究项目。对登陆tc的降水预测最具挑战性的一方面是降水强度和范围，另一方面是降水的空间分布，特别是最大雨区。TC降雨的分布和不对称性是与TC引起的内陆洪水和TC大小变化内在联系的重要特征。这项工作的总体目标是通过长期卫星观测的统计分析，了解TCs登陆过程中降雨的分布、演变和不对称性。该项目将研究影响登陆tc在登陆前、期间和之后阶段的降雨模式变化的物理过程，以及登陆tc与海洋上tc的对比。在这些过程中要考虑的因素包括日变化、温带转变和其他环境条件，如垂直风切变、总有效水分和海面温度。本研究将重点研究热带气旋登陆过程中降水变化的物理过程以及对热带气旋登陆的环境影响，从而填补我们对热带气旋降雨演变的科学认识的关键空白。更好地了解这些TC特征对于改进登陆TC预报至关重要。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。

Inland freshwater flooding induced by heavy rainfall has been one of the most deadly and costly disasters produced by landfalling hurricanes or tropical cyclones (TCs). In contrast to the great progress in understanding and predicting TC tracks and moderate progress in TC intensity changes, quantitative rainfall forecast of TCs is still a challenge issue, and little progress has been made. This project seeks to advance our understanding of TC rainfall distribution by focusing on interactions between landfalling TCs and the atmospheric environment and to improve quantitative rainfall forecast of TCs during TC landfall. The principal investigator will foster involvement of a graduate student with particularly consideration of women and underrepresented minority students in carrying out this research project. The most challenging aspect of predicting rainfall in landfalling TCs is not only the intensity and the extent but also the spatial distribution of precipitation especially the heaviest rainfall area. The distribution and asymmetries of TC rainfall are important features inherently linked to TC-induced inland flooding and TC size changes. The overall goal of the work is to understand distribution, evolution, and asymmetries of rainfall during landfalling processes of TCs through statistical analyses of long-term satellite observations. This project will examine physical processes that influence changes of rainfall patterns for landfalling TCs in before, during, and after landfall stages, and for landfalling versus over-ocean TCs. Factors to be considered in these processes include diurnal variation, extratropical transition, and other environmental conditions such as vertical wind shear, total available moisture, and sea surface temperatures. The research will fill a critical gap in our scientific understanding of TC rainfall evolution by focusing on physical processes of precipitation changes during landfalling TCs and environmental impacts on landfalling TCs. A better understanding of these TC features is essential for improving landfalling TC forecasts.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.