Troposphere-stratosphere coupling and linkages to high latitude climate variability

对流层-平流层耦合及其与高纬度气候变率的联系

• 批准号: 0909459
• 负责人: Judah Cohen
• 金额: $ 29.99万
• 依托单位: Atmospheric and Environmental Research Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0909459&HistoricalAwards=false
• 关键词: Troposphere; stratosphere; coupling; linkages; latitude

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).AbstractThe leading statistical mode of winter climate variability for the extratropical Northern Hemisphere, a same-signed height anomaly stretched across the polar cap and an opposite-signed anomaly centered over the respective ocean basins of the mid-latitudes, has received much attention from the science community. Research continues to demonstrate its importance to interannual signals and trends in climate variability and that it does not appear to be related to ENSO. A relationship has been demonstrated between this dominant mode in winter and seasonal snow cover at high latitudes in the fall. Analysis of height anomalies around the polar cap demonstrate that the genesis of the dominant winter climate mode involves coupling between the stratosphere and the troposphere. Moreover, stratosphere troposphere coupling is initiated by variability in the Eliassen-Palm (EP) flux at mid- to high-latitudes. This project will develop and expand our concept that the pattern associated with the dominant winter mode of variability for the Northern Hemisphere results from interactions among the different components of the land atmosphere climate system at high-latitudes. The team will investigate how the pattern can be forced, both locally and remotely, by boundary perturbations, through observational analysis and numerical modeling experiments of varying complexity. Though a statistically significant relationship can be shown between seasonal snow cover, the EP flux and polar cap heights, what remains unclear is the atmospheric bridge that connects the snow cover forcing and the EP flux and polar cap response, which are separated in time by a month or more. The emphasis of the research will be on the time interval that spans the snow cover advance in October and the major EP flux pulse during the early winter. Hypotheses are presented for the long lead-lag and a series of GCM experiments will test each hypothesis. Furthermore GCM experiments are proposed to test whether snow cover is an active driver of stratosphere-troposphere coupling or rather a passive leading indicator, itself a common response to forcing from the atmosphere or some other boundary forcing.

该奖项是根据2009年美国复苏和再投资法案（公法111-5）。AbstractThe领先的统计模式的冬季气候变率的外热带北方半球，一个相同的签署高度异常延伸整个极冠和一个相反的签署异常集中在各自的海洋盆地的中纬度地区，受到了科学界的广泛关注。研究继续表明它对气候变化的年际信号和趋势的重要性，而且它似乎与厄尔尼诺/南方涛动无关。这种主导模式在冬季和季节性积雪之间的关系已被证明在高纬度地区的秋季。对极冠周围高度异常的分析表明，冬季主导气候模式的形成涉及平流层和对流层之间的耦合。此外，平流层对流层耦合是由中高纬度Eliassen-Palm（EP）通量的变化引起的。本项目将发展和扩大我们的概念，即与北方半球冬季主要变率模式有关的模式是高纬度陆地大气气候系统不同组成部分之间相互作用的结果。该团队将通过观测分析和不同复杂性的数值模拟实验，研究边界扰动如何在本地和远程强制这种模式。虽然季节性积雪，EP通量和极冠高度之间存在统计学上的显著关系，但仍不清楚的是连接积雪强迫和EP通量和极冠响应的大气桥梁，它们在时间上相隔一个月或更长。研究的重点是10月积雪推进的时间间隔和初冬期间的主要EP通量脉冲。提出了长超前滞后的假设，并通过一系列GCM实验对每个假设进行了检验。此外，GCM实验提出测试积雪是否是一个积极的驱动程序的平流层对流层耦合，而是一个被动的领先指标，本身是一个共同的响应，迫使从大气或其他一些边界强迫。