An Investigation of the Dynamic and Thermodynamic Processes that Lead to Distinctly Different Pathways to Tropical Cyclogenesis

对导致热带气旋形成截然不同途径的动力和热力学过程的研究

• 批准号: 1415244
• 负责人: Melville Nicholls
• 金额: $ 36.65万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1415244&HistoricalAwards=false
• 关键词: Investigation; Dynamic; Thermodynamic; Processes; Lead

The formation of tropical storms and hurricanes, known as tropical cyclogenesis, is a complex process involving interactions between the large-scale environment and a smaller-scale atmospheric disturbance passing through. There have been multiple theories developed to try to describe the pathway that a disturbance takes on its road to becoming a tropical storm. In this project, researchers will use advanced, high-resolution numerical modeling to analyze the processes involved in two of these pathways. Improved knowledge of how tropical cyclones form will aid forecasters and improve public safety, especially in the cases where small storms develop very close to populated areas. This award will also provide a training opportunity for a graduate student. The first pathway to tropical cyclogenesis is characterized by a spin up of cyclonic surface winds and vorticity building in the center of deep convective towers. The second is characterized by a mid-level vortex that is followed by a small surface concentrated vortex near the center of the large scale circulation. The research plan is to conduct idealized numerical experiments using the Regional Atmospheric Modeling System (RAMS) with new riming and surface flux schemes and the Weather Research and Forecasting (WRF) model with moving nested grids. The main objectives that the project will address are to: 1) Determine the physical mechanisms responsible for the development of strong mid-level vortices and the conditions that favor their occurrence, 2) Identify the processes leading to the formation of a small surface concentrated vortex, and 3) Determine the effect of vertical wind shear, including a mean flow, on the pathway taken to tropical cyclogenesis.

热带风暴和飓风的形成，称为热带气旋，是一个复杂的过程，涉及大尺度环境与经过的小尺度大气扰动之间的相互作用。 人们已经开发出多种理论来试图描述扰动演变为热带风暴的路径。 在这个项目中，研究人员将使用先进的高分辨率数值模型来分析其中两个途径所涉及的过程。 提高对热带气旋形成方式的了解将有助于预报员并改善公共安全，特别是在小风暴在人口稠密地区附近发展的情况下。 该奖项还将为研究生提供培训机会。热带气旋形成的第一个途径的特点是气旋表面风的旋转和深对流塔中心涡度的形成。 第二个特征是中层涡旋，随后是大尺度环流中心附近的小表面集中涡旋。 该研究计划是使用具有新的雾化和表面通量方案的区域大气模拟系统（RAMS）以及具有移动嵌套网格的天气研究和预报（WRF）模型来进行理想化的数值实验。 该项目的主要目标是：1）确定产生强中层涡旋的物理机制以及有利于其发生的条件，2）确定导致形成小型表面集中涡旋的过程，以及3）确定垂直风切变（包括平均流）对热带气旋发生路径的影响。