The annual cycle in lower stratospheric temperatures revisited
The annual cycle in lower stratospheric temperatures revisited
复制标题
DOI：
10.5194/acp-11-3701-2011
复制
发表时间：
2010-11
影响因子：
6.3
通讯作者：
S. Fueglistaler;P. Haynes;P. Forster
中科院分区：
文献类型：
--
作者：
S. Fueglistaler;P. Haynes;P. Forster
观测到的平流层较低温度显示出明显的年度周期。热带和北半球的周期是同相的，而南半球的周期是相反的。在一篇优雅而有影响的论文中，Yulaeva，Holton和Wallace(1994)解释说，观测到的模式是平流层环流动力强迫中半球不对称的直接结果。结果表明，在微波探测单元通道4(加权中心在平流层下部)资料中，温带和热带温度周期的组合几乎补偿了热带和温带温度的不同变化，并将其解释为对波驱动的剩余环流年周期的温度响应。我们证明了Yulaeva等人观测到的温度变化的近补偿性。(1994)是MSU-4通道的加权函数的产物，不适用于单个压力水平。我们详细讨论了温度变化补偿所需的条件，以及从热带、温带和全球平均温度变化的分析中可以得到哪些启示。平流层低层臭氧的动态季节变化导致季节温度循环的放大，特别是在热带地区。静态稳定度的纬向结构也导致了对热带和综合温带温度变化的补偿显著偏离。与Yulaeva等人的观点一致。(1994)我们肯定了热带和温带外温度年循环中的拉锯模式为年际变化和趋势的机制模式提供了一个重要的指针，但我们还得出结论，动态引起的臭氧变化对温度的反馈和静态稳定度的纬度结构应该被包括在这些模式中作为主导顺序过程。
Observed lower stratospheric temperatures show a prominent annual cycle. The cycles in the tropics and North- ern Hemisphere are in phase and the cycle in the Southern Hemisphere has the opposite phase. In an elegant and influ- ential paper, Yulaeva, Holton and Wallace (1994) explained the observed pattern as a direct consequence of hemispheric asymmetries in the dynamical forcing of the stratospheric circulation. They showed that in Microwave Sounding Unit channel 4 (weighting centered in the lower stratosphere) data the combined extratropical and the tropical temperature cy- cle nearly compensate and interpreted the out-of-phase tem- perature variations between tropics and extratropics as the temperature response to an annual cycle in the wave driven residual circulation. We show that the near-compensation of temperature variations observed by Yulaeva et al. (1994) is artefact of the weighting function of the MSU-4 channel and does not hold on individual pressure levels. We discuss in detail the conditions required that temperature variations compensate, and what insights can be obtained from anal- ysis of tropical, extratropical and global mean temperature variations. Dynamically induced seasonal variations of lower stratospheric ozone lead to an amplification of the seasonal temperature cycle particularly in the tropics. The latitudinal structure of static stability also induces a significant deviation from compensation of tropical and combined extratropical temperature variations. In line with Yulaeva et al. (1994) we affirm that the see-saw pattern in the annual cycles of tropical and combined extratropical temperatures provides an impor- tant pointer to mechanistic models for interannual variability and trends, but additionally conclude that the feedback of dy- namically induced ozone variations on temperatures and the latitudinal structure of static stability should be included as leading order processes in such models.