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AGS-PRF的这一提议，研究人员将使用一系列模型来研究臭氧和太阳变率变化对布鲁尔-多布森环流(BDC)的影响。BDC是平流层中赤道上升、极点附近下沉的经向垂直环流，它在决定平流层臭氧的经向分布和极地臭氧浓度方面起着关键作用。最近的工作表明，BDC有两个分支，一个浅的分支局限于平流层下部，而上层的分支延伸到中下层的高度。结果表明，由于副热带和温带波强迫的变化，由于全球变暖，热带下支的热带上升流将会增加，这是目前还不清楚的。一个可能的因素是副热带急流加速，也是决定地形重力高度和Rossby波强迫的波浪破碎的临界层。这导致临界层的高度上升，从而增加了重力波对平流层的穿透。PI还指出，虽然全球变暖预计会导致急流的极地移动，但臭氧的恢复预计会产生相反的影响，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(GHGs)和11年太阳周期的变化做出反应。新获得的太阳可变性数据集表明，关键紫外线波长范围内的太阳可变性可能比之前所知的大4-6倍。因此，需要确定对11年太阳周期的反应。PI建议使用一系列模型来研究BDC的变化，其中包括预测臭氧浓度的全物理、全化学全大气社区气候模式(WACCM)，以及规定了臭氧和其他微量气体的特定化学WACCM(SC-WACCM)。此外，PI将发展和使用更简单的理想化大气环流模式(IGCM)，这是一个干式动力核心模式，具有辐射-光化学平衡和微扰加热(我相信)的热弛豫，以表示从WACCM的观测或未来气候情景积分中指定的臭氧变化。因此，PI将实现三个目标：(1)检查臭氧损失和恢复的高度、纬度和半球结构的变化如何结合在一起产生BDC的变化；(2)确定新修订的太阳周期测量结果将如何影响BDC，以及这些变化与以前的BDC-太阳周期分析相比如何；以及(3)确定SC-WACCM和理想化的IGCM是否能够以足够的保真度再现WACCM完整版的结果，从而使它们成为以计算费用的一小部分研究气候变化的可行工具。