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

该项目将研究平流层环流和臭氧年际变化的动力机制，这些变化也影响对流层的季节性气候，特别是在冬季。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(例如北大西洋涛动/北极涛动)的季节性异常有关，这对欧洲和北美的气候和天气产生了深远影响。平流层低层臭氧的变化也与动力学密切相关：高纬度臭氧的分布是由布鲁尔-多布森翻转环流决定的，紫外线和热带臭氧吸收产生的辐射加热反过来又影响温度和热风的分布。Salby和Callaghan博士将对年际变化进行动态定向分析，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将使用等熵坐标下的3D原始方程模型进行分析。该项目将增进对平流层环流强迫和成分变异性的理解，从而改进对对流层-平流层相互作用和季节至年际时间尺度上变异性的模拟。这项研究还将对理解北半球观测到的臭氧消耗的原因做出重大贡献。

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.