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A. Chandran R.L. Collins V.L. Harvey 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
In this review article we summarize recent results in the coupling of the stratosphere–mesosphere during stratospheric sudden warming (SSW) events. We focus on the role of planetary and gravity waves in driving the middle atmosphere circulation and illustrate the stratosphere–mesosphere coupling during undisturbed wintertime circulation, during an SSW event, and after an SSW event during the formation of an elevated stratopause using simulations of past Arctic and Antarctic winters from the Specified Dynamics version of the Whole Atmosphere Community Climate Model (SD-WACCM). We illustrate the transition of the polar stratopause from being a gravity wave driven phenomena to a planetary wave driven phenomena during SSW events and its subsequent reestablishment and control by gravity waves. We also examine the synoptic structure of the stratosphere, mesosphere, and lower thermosphere using SD-WACCM data fields that show the structure of the vortex during specific dynamical events in both hemispheres. We illustrate the longitudinal asymmetry in the thermal structure in the stratosphere and mesosphere driven by differences in circulation over the polar cap regions during an SSW event. We complement this analysis of the middle atmosphere circulation with a classification of both the Arctic and Antarctic winters since 1979 into major, minor, elevated stratopause or quiet winters based on the level of disturbance using the Modern Era-Retrospective Analysis for Research and Applications (MERRA) reanalysis data. From the MERRA data we find that the combined occurrences of both major and minor warmings in the Arctic have remained constant over the past three decades while we find a minor increase in their occurrences in the Antarctic. 相似文献
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球柱三维分离及涡流的数值模拟 总被引:1,自引:0,他引:1
对三维可压非定常N-S方程进行有限体积中心离散,并用Runge-Kuta显式格式进行数值求解。数值模拟了球柱分离及涡流的形态结构,给出了具有激波、边界层、大分离区、涡流及其间相互干扰的复杂流型 相似文献
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雷凌航 《中国民航飞行学院学报》2013,(1):77-80
2011中国民航十大热点事件网络票选中,“国内首架A380交付南方航空公司”排名榜首。南航围绕A380首飞进行的一系列市场策划与公关营销,获得了产品经济效益与品牌美誉度的双赢,被业界称为“一架飞机引发的公关大案”。分析此次产品营销中南方航空的营销策略,对国内航空公司市场理念的拓展,品牌实力的建设,有着积极的启示意义与实践价值。 相似文献