Nighttime secondary ozone layer during major stratospheric sudden warmings in specified‐dynamics WACCM
Nighttime secondary ozone layer during major stratospheric sudden warmings in specified‐dynamics WACCM
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DOI：
10.1002/jgrd.50651
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发表时间：
2013-08
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通讯作者：
Olga V. Tweedy;V. Limpasuvan;Y. Orsolini;Anne K. Smith;R. Garcia;D. Kinnison;C. Randall;Ole-Kristian Kvissel;F. Stordal;V. Harvey;A. Chandran
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作者：
Olga V. Tweedy;V. Limpasuvan;Y. Orsolini;Anne K. Smith;R. Garcia;D. Kinnison;C. Randall;Ole-Kristian Kvissel;F. Stordal;V. Harvey;A. Chandran
平流层突然变暖（SSW）强烈影响整个中层大气直到热层。目前，SSW期间大气动力学对中间层-低热层（MLT）极地臭氧的作用还没有很好的了解。在这里，我们通过研究对臭氧重要的关键物种（如H和O）的动态和分布来研究SSW引起的夜间“次级”（90-105 km）臭氧最大值的变化。我们使用国家大气研究中心全大气社区气候模式与“特定动力学”（SD-WACCM）的输出，其中模拟受到低于1 hPa的气象再分析的约束。合成材料是基于六个主要的SSW事件与升高的平流层顶事件。个别SSW的情况下，温度和MLT夜间臭氧的模型进行比较，对探测大气层使用宽带发射辐射测量观测搭载美国宇航局的热层电离层中层能量学和动力学（TIMED）卫星。臭氧和主要化学痕量物种的演变与异常的垂直剩余运动在SSWs和光化学平衡管理的MLT夜间臭氧一致。就在SSW发病后，增强的上升流对流冷却极地地区从80至100公里，并从下面输送低H。这些条件促使次级臭氧层中的浓度增加。随后从较低的热层下沉温暖的MLT和增强的H从热层水库的下降，从而限制了二次臭氧浓度的增加。二次臭氧与温度和H的负相关性在有SSW的冬季比在无SSW的冬季更明显。
A major stratospheric sudden warming (SSW) strongly impacts the entire middle atmosphere up to the thermosphere. Currently, the role of atmospheric dynamics on polar ozone in the mesosphere‐lower thermosphere (MLT) during SSWs is not well understood. Here we investigate the SSW‐induced changes in the nighttime “secondary” (90–105 km) ozone maximum by examining the dynamics and distribution of key species (like H and O) important to ozone. We use output from the National Center for Atmospheric Research Whole Atmosphere Community Climate Model with “Specified Dynamics” (SD‐WACCM), in which the simulation is constrained by meteorological reanalyses below 1 hPa. Composites are made based on six major SSW events with elevated stratopause episodes. Individual SSW cases of temperature and MLT nighttime ozone from the model are compared against the Sounding of the Atmosphere using Broadband Emission Radiometry observations aboard the NASA's Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite. The evolution of ozone and major chemical trace species is associated with the anomalous vertical residual motion during SSWs and consistent with photochemical equilibrium governing the MLT nighttime ozone. Just after SSW onset, enhanced upwelling adiabatically cools the polar region from 80 to 100 km and transports low H from below. These conditions promote a concentration increase in the secondary ozone layer. Subsequent downwelling from the lower thermosphere warms the MLT and enhances the descent of H from the thermospheric reservoir, thereby limiting the secondary ozone concentration increase. Negative correlation of secondary ozone with respect to temperature and H is more pronounced during winters with SSWs than during non‐SSW winters.