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Studies in Large-Scale Circulation and Wave Dynamics

大尺度环流和波浪动力学研究

基本信息

批准号：
8903340
负责人：
Ka-Kit Tung
金额：
$ 23.3万
依托单位：
University of Washington
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
1989
资助国家：
美国
起止时间：
1989-06-15 至 1992-11-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=8903340&HistoricalAwards=false
关键词：
Studies Large Scale Circulation Wave

项目摘要

Large-scale planetary waves and circulations in the extra- tropical atmosphere are known to have important low-frequency variability, which affects weather and climate. In this project, the emphasis will be on studying the various mechanisms that can possibly couple the tropics to the extra-tropics and their role in affecting the year-to-year changes in the extra-tropical circulation and wave dynamics. The existence of the phenomenon of extra-tropical Quasi- Biennial Oscillation provides a focus for this theoretical study. Newly available observational analyses on this phenomenon also provide critical checks on the relevance of the proposed mechanisms of tropical-extra-tropical coupling. The approach will be one of hypothesis testing. Several essentially two- dimensional and some three-dimensional mechanisms have been proposed so far: through induced change in the mean meridional circulation (Hadley and Brewer-Dobson circulations), through transport of tropical perturbations by the preexisting circulation, and through modulations in the wave guide for planetary waves in the extra-tropics. The relevance of each will be tested with mechanistic model studies and by critically comparing the model results with available observation. This research is an important component of the basic theoretical studies required as an underpining for the development of prediction models for low frequency weather and climate phenomena.

众所周知，热带外大气中的大尺度行星波和环流具有重要的低频变化，这会影响天气和气候。在这个项目中，重点将是研究可能将热带与温带耦合起来的各种机制，以及它们在影响热带外环流和波动动力学年际变化方面的作用。热带外准两年振荡现象的存在为这一理论研究提供了一个焦点。新获得的对这一现象的观测分析也为所提出的热带-热带外耦合机制的相关性提供了关键的检验。这种方法将是一种假设检验。到目前为止，已经提出了几种本质上是二维和一些三维的机制：通过平均经向环流(Hadley环流和Breyer-Dobson环流)的诱导变化，通过先前存在的环流输送热带扰动，以及通过对热带外行星波的波导调制。将通过机械论模型研究以及将模型结果与现有观测结果进行批判性比较来检验每个模型的相关性。这项研究是发展低频天气和气候现象预报模型所需的基础理论研究的重要组成部分。