Presistent Jets in Broad Baroclinically Unstable Regions

广泛的斜压不稳定区域持续喷流

• 批准号: 8907714
• 负责人: R. Lee Panetta
• 金额: $ 7.45万
• 依托单位: Texas A&M Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-03-01 至 1991-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8907714&HistoricalAwards=false
• 关键词: Presistent; Jets; Broad; Baroclinically; Unstable

East-west oriented jets are observed in the high latitudes of the troposphere, the oceans and other planetary atmospheres. Explanations of "eddy-forced" zonal jets usually require some external influence, such as geometrical boundaries or localized forcing, to account for their spatial persistence. Preliminary calculations indicate that, when motions are quasi-geostrophic, energy arising from the instability of an imposed, spatially uniform, north-south temperature gradient can be organized into jets of a persistence not directly linked to feature of the forcing. The scale of the jet is self-determined, so that once a region is sufficiently wide to support one jet, further widening of the region increases the number of jets. The goal of this research project is to examine the source of this persistence and its scale using (relatively) simple two- layer models embodying various numbers of wave-wave interactions. Special attention will be paid to how maintenance and persistence are affected during the transition from a regime that supports a single jet to one supporting two. The influence of linear wave dynamics in determining the scale of the jets will be examined using different indices of wave activity. An examination of the transition regime may also indicate which low frequency processes play a prominent role in the Northern Hemisphere where a second jet does not emerge.

在对流层，海洋和其他行星氛围的高纬度中观察到了面向西方的喷气机。 “涡流”纬向喷气机的解释通常需要一些外部影响，例如几何边界或局部强迫，以解释其空间持久性。 初步计算表明，当运动是准地藻时，由于施加的，空间均匀的，南北温度梯度的不稳定性而产生的能量可以将其组织成持久性与强迫特征的持久性的射流。 射流的尺度是自决的，因此一旦一个区域足够宽以支撑一台喷射，该区域的进一步扩大就会增加喷气机的数量。 该研究项目的目的是使用（相对）简单的两层模型来检查这种持久性及其规模的来源，这些模型体现了各种波浪波相互作用。 从支持单个喷气机的政权过渡到支撑两个机构的过渡期间，将特别注意维护和持久性如何受到影响。 线性波动力学在确定喷射尺度上的影响将使用波活性的不同指标进行检查。 对过渡状态的检查还可能表明哪些低频过程在北半球没有出现的北半球起着重要作用。