Role of the Stratosphere in 11-Yr Solar Forcing of Surface Climate: Diagnostic Comparisons of Observations With Model Simulations

该项目考虑平流层下部和地面气候对伴随着11年太阳黑子周期的日照变化的反应。 据推测，日照变化会影响平流层温度，因为太阳紫外线辐射的增加会导致平流层臭氧的增加，而臭氧的增加又会导致平流层温度的增加（在热带地区最高）和中纬度纬向风的增加。 增加的平流层纬向风通过与“向下控制”机制有关的波-平均流相互作用影响较低层的环流，产生一种海平面气压异常模式，包括两极的低压和北太平洋北方的高压。 在该奖项下开展的工作将在两个气候模型的模拟中审查太阳变化对地表气候影响的这种“自上而下”的机制，其中一个模型通过卫星观测具体说明太阳引起的臭氧异常，另一个模型（全大气层共同体气候模型，WACCM）根据日照变化在模型内部产生臭氧变化。 在WACCM模拟中，将根据其光谱分布的几种估计来规定日射变化，以确定对11年太阳强迫的紫外线分量中的不确定性的响应的敏感性。 还将使用WACCM模拟来探索对包括平流层准两年期振荡阶段在内的其他因素的反应的敏感性，这项工作将通过对一名研究生的支持和培训产生更广泛的影响，这将培养这一科学领域的科学工作者。此外，更好地了解太阳变率对气候的影响，可能有助于了解气候对外部强迫的敏感性，以及决定气候反应的机制。 这些信息可能有益于参与气候变化政策决定的决策者。

This project considers the response of lower stratospheric and surface climate to the changes in insolation accompanying the 11-year sunspot cycle. Insolation changes are hypothesized to affect stratospheric temperature as increases in solar ultraviolet (UV) radiation cause increases in stratospheric ozone which in turn lead to increases in stratospheric temperature (maximizing over the tropics) and midlatitude zonal winds. The increased stratospheric zonal winds then affect circulation at lower levels through the wave-mean flow interactions associated with the "downward control" mechanism, producing a pattern of sea level pressure anomalies including low pressure over the poles and high pressure over the northern North Pacific. Work conducted under this award would examine this "top down" mechanism for the influence of solar variability on surface climate in simulations from two climate models, one in which the solar-induced ozone anomalies are specified from satellite observations, and another (the Whole Atmosphere Community Climate Model, or WACCM) in which the ozone changes are generated internally by the model in response to the insolation change. In the WACCM simulations, the insolation change will be prescribed according to several estimates of its spectral distribution, to determine the sensitivity of the response to uncertainty in the UV component of the 11-year solar forcing. WACCM simulations will also be used explore the sensitivity of the response to additional factors including the phase of the stratospheric quasi-biennial oscillation.The work will have broader impacts through the support and training of a graduate student, which will develop the scientific workforce in this scientific area. In addition, a better understanding of the impact of solar variability on climate may prove useful for understanding the sensitivity of climate to external forcing, and the mechanisms which determine the climatic response. Such information may benefit decision makers engaged in policy decisions regarding climate change.