Interannual Changes of Stratospheric Dynamical and Chemical Structure and Their Relationship to Changes of the Residual Circulation

该项目将调查平流层环流和臭氧产生年际变化的动力机制，这种变化也影响对流层的季节性气候，特别是冬季。平流层极涡的变化已被证明与对流层纬向平均纬向风和环流模式的季节性异常有关（例如，北大西洋涛动/北极涛动），它深刻地影响了欧洲和北美的气候和天气。平流层下部的臭氧变化也与动力学密切相关：高纬度地区的臭氧分布由布鲁尔-多布森翻转环流决定，臭氧吸收紫外线和热波段的辐射加热反过来又影响温度和热成风的分布。Salby和Callaghan博士将对年际变化进行动态分析，以确定平流层环流对对流层强迫（行星波活动的向上通量）和平流层动力结构（准两年振荡阶段）的敏感性。PI将使用等熵坐标中的3D原始方程模型进行分析。该项目将促进对平流层环流和成分变化的强迫的理解，从而改进对流层-平流层相互作用和季节至年际时间尺度变化的建模。这项研究还将大大有助于了解在北方观测到的臭氧消耗的原因。

The project will investigate the dynamical mechanisms producing interannual changes in stratospheric circulation and ozone, which also influence the seasonal climate of the troposphere, notably in winter. Variations in stratospheric polar vortex have been shown linked to seasonal anomalies in tropospheric zonal-mean zonal winds and circulation patterns (e.g., North Atlantic Oscillation/ Arctic Oscillation), which profoundly impact the European and North American climate and weather. Ozone variations in the lower stratosphere are also strongly linked with dynamics: The ozone distribution in the high latitudes is determined by the Brewer-Dobson overturning circulation, and radiative heating from ozone absorption in the ultraviolet and thermal bands, in turn, influences the temperature and thermal wind distribution. Drs. Salby and Callaghan will conduct a dynamically oriented analysis of interannual variability to ascertain the sensitivity of the stratosphere circulation to tropospheric forcing (upward fluxes of planetary wave activity) and stratospheric dynamical structure (Quasi-biennial oscillation phase). The PIs will use a 3D primitive equation model in isentropic coordinates for the analysis. The project will advance understanding of the forcing of circulation and constituent variability in the stratosphere, which will lead to improved modeling of troposphere-stratosphere interactions and variability on the seasonal-to-interannual time scales. This research should also significantly contribute in understanding the causes of observed ozone depletion in the northern hemisphere.