AGS-PRF: A Hierarchical Modeling Approach to Quantifying the Effects of Changes in Ozone and Solar Variability on the Brewer-Dobson Circulation and Tropospheric Climate

AGS-PRF：量化臭氧和太阳变率变化对布鲁尔-多布森环流和对流层气候影响的分层建模方法

• 批准号: 1331341
• 负责人: John Albers
• 金额: $ 8.6万
• 依托单位: Albers John R
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1331341&HistoricalAwards=false
• 关键词: AGS; PRF; Hierarchical; Modeling; Approach

Under this AGS-PRF proposal, the researcher will use a hierarchy of models to examine the effects of changes in ozone and solar variability on the Brewer-Dobson circulation (BDC). The BDC is a meridional-vertical circulation in the stratosphere with rising motion at the equator and sinking near the poles, and it plays a key role in determining the meridional distribution of stratospheric ozone and the concentration of ozone in the polar stratosphere. Recent work suggests that the BDC has two branches, a shallow one confined to the lower stratosphere and an upper one which extends as high as the lower mesosphere. Results indicate that the tropical upwelling in the lower branch will increase as a consequence of global warming, because of changes in subtropical and extratropical wave forcing which are not well understood. A likely contributing factor is the subtropical jet streams accelerate, and so too the critical layer for wave breaking that determines the height of orographic gravity and Rossby wave forcing. This results in a rising of the height of the critical layer and hence an increase in the penetration of gravity waves into the stratosphere. The PI also notes that while global warming is expected to cause poleward shifts of the jet streams, ozone recovery is expected to have the opposite effect, and both have consequences for the driving of the BDC by midlatitude gravity waves. In addition, the deep branch of the BDC is expected to respond to changes in ozone, greenhouse gases (GHGs), and the 11-year solar cycle. Newly derived solar variability data sets suggest that solar variability in the key UV wavelength range may be 4-6 times larger than previously understood. Thus there is a need to determine the response to the 11-year solar cycle. The PI proposes to study BDC change using a hierarchy of models which includes the full-physics, full-chemistry Whole Atmosphere Community Climate Model (WACCM), with prognostic ozone concentration, and the Specified Chemistry WACCM (SC-WACCM), in which ozone and other trace gases are prescribed. In addition, the PI will develop and use a simpler Idealized General Circulation Model (IGCM), a dry dynamical core model with thermal relaxation to a radaitive-photochemical equilibrium and perturbation heating (I believe) to represent changes in ozone specified from either observations or future climate scenario integrations of WACCM. Thus the PI will accomplish three goals: (1) examine how changes in the height, latitude, and hemispheric structure of ozone loss and recovery combine to produce changes in the BDC; (2) determine how the newly revised measurements of the solar cycle will affect the BDC and how these changes compare to previous BDC-solar cycle analysis; and (3) determine whether SC-WACCM and the idealized IGCM can reproduce the results of the full version of WACCM with enough fidelity as to make them viable tools for studying climate change at a fraction of the computational expense.

根据这项 AGS-PRF 提案，研究人员将使用层次模型来研究臭氧变化和太阳变率对布鲁尔-多布森环流 (BDC) 的影响。 BDC是平流层中的一种经向垂直环流，在赤道处上升，在两极附近下沉，它​​对平流层臭氧经向分布和极地平流层臭氧浓度起着关键作用。最近的研究表明，BDC 有两个分支，一个浅分支局限于平流层下部，一个上部分支延伸至中层下部。结果表明，由于全球变暖，下支的热带上升流将会增加，因为副热带和温带波浪强迫的变化尚不清楚。一个可能的影响因素是副热带急流加速，因此也是决定地形重力和罗斯贝波强迫高度的波浪破碎的关键层。这导致临界层高度上升，从而增加重力波对平流层的穿透力。 PI还指出，虽然全球变暖预计会导致急流向极地移动，但臭氧恢复预计会产生相反的效果，并且两者都会对中纬度重力波驱动BDC产生影响。此外，BDC的深层分支预计将对臭氧、温室气体（GHG）和11年太阳周期的变化做出反应。 新得出的太阳变化数据集表明，关键紫外线波长范围内的太阳变化可能比之前理解的大 4-6 倍。因此需要确定对 11 年太阳活动周期的响应。 PI 建议使用一系列模型来研究 BDC 变化，其中包括具有预测臭氧浓度的全物理、全化学全大气社区气候模型 (WACCM) 和特定化学 WACCM (SC-WACCM)，其中臭氧和其他微量气体都有规定。此外，PI将开发和使用更简单的理想化大气循环模型（IGCM），这是一种干动力核心模型，具有热弛豫到辐射光化学平衡和扰动加热（我相信）来表示观测或指定的臭氧变化WACCM 的未来气候情景整合。因此，PI将实现三个目标：（1）研究臭氧损失和恢复的高度、纬度和半球结构的变化如何结合起来产生BDC的变化； (2) 确定新修订的太阳周期测量将如何影响 BDC 以及这些变化与之前的 BDC 太阳周期分析相比如何； (3) 确定 SC-WACCM 和理想化的 IGCM 是否能够以足够的保真度重现完整版 WACCM 的结果，从而使其成为以一小部分计算费用研究气候变化的可行工具。