Large Scale Influences on Tropical Cyclogenesis

对热带气旋发生的大规模影响

• 批准号: 9900671
• 负责人: John Molinari
• 金额: $ 32.93万
• 依托单位: SUNY at Albany
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-15 至 2002-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9900671&HistoricalAwards=false
• 关键词: Large; Scale; Influences; Tropical; Cyclogenesis

The objective of this research is to increase understanding of the genesis of tropical cyclones. Of particular interest are the influences on genesis of phenomena whose scales are larger than the tropical cyclone and, therefore, more likely to be measured accurately. There is considerable disagreement in the community regarding the relative importance of the large-scale phenomena and the specific ways in which they affect the process. This project consists of three related tasks. One is a continuation of observational studies, using gridded analyses, of the pre-cursors to cyclogenesis in the eastern Pacific, particularly the relative roles of the background state, mountain interactions, upstream atmospheric waves, and wind surges. The PI also will investigate the role of the monsoon trough in this region. The other two tasks deal with the phenomenon of easterly waves. A global climatology of sign reversals in the meridional gradient of potential vorticity and its influence on easterly waves and cyclogenesis will be completed. In addition, numerical simulations of easterly waves will be conducted, beginning with a simple shallow water model and moving to the more complex MM5 model. Improved understanding of the processes involved in tropical cyclogenesis is a key step in improving the forecasting of tropical cyclones.

这项研究的目的是增加对热带气旋成因的了解。特别令人感兴趣的是对尺度大于热带气旋的现象发生的影响，因此更有可能被准确测量。对于大规模现象的相对重要性及其影响进程的具体方式，社会上存在相当大的分歧。这个项目包括三个相关的任务。其一是继续使用网格分析对东太平洋气旋发生的前兆进行观测研究，特别是背景状态、山脉相互作用、上游大气波和风浪的相对作用。PI还将调查季风槽在这一地区的作用。另外两项任务涉及东风波现象。位势涡度经向梯度的符号反转及其对东风波和气旋生成的影响的全球气候学将完成。此外，还将对东风波进行数值模拟，从一个简单的浅水模式开始，转移到更复杂的MM5模式。加强对热带气旋发生过程的了解是改进热带气旋预报的关键一步。