Tropospheric intrusions associated with the secondary tropopause
Tropospheric intrusions associated with the secondary tropopause
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DOI：
10.1029/2008jd011374
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发表时间：
2009-05
影响因子：
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通讯作者：
L. Pan;W. Randel;J. Gille;William D. Hall;B. Nardi;S. Massie;V. Yudin;R. Khosravi;P. Konopka;D. Tarasick
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文献类型：
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作者：
L. Pan;W. Randel;J. Gille;William D. Hall;B. Nardi;S. Massie;V. Yudin;R. Khosravi;P. Konopka;D. Tarasick
利用新的观测资料和气象分析，研究了对流层空气进入副热带急流上方平流层下层的深层侵入。这些侵入物具有低臭氧浓度和低静态稳定性的特点。臭氧探空仪剖面和Aura/HIRDLS卫星遥感数据一致地观测到低臭氧层。侵入层出现在向极地延伸的热带对流层顶沿线和下方，成为中高纬地区的次级对流层顶。臭氧与热结构的关联为副热带对流层顶断裂和次级对流层顶的物理意义提供了证据。入侵层的核心通常在370 ~ 400k位温（~ 15 km）之间，但入侵的垂直范围可以影响400k以上的臭氧，即上世界的下边界。通过对2007年春季美国大陆两次入侵事件的分析，揭示了入侵气团的空间范围和时间演变。这些实例证明了潜在温度递减率（即静态稳定性）作为入侵事件诊断的有效性。通过与位涡场的比较，说明了两种动力场的互补性。静稳定性诊断提供了一种工具来绘制侵入层的水平范围并研究其演变。此外，该诊断还为现场研究提供了入侵事件预测的可能。
[1] Deep intrusions of tropospheric air into the lower stratosphere above the subtropical jet are investigated using new observations and meteorological analyses. These intrusions are characterized by low ozone concentration and low static stability. The low-ozone layer is consistently observed from ozonesonde profiles and satellite remote sensing data from Aura/HIRDLS. The intruding layer occurs along and under the poleward extending tropical tropopause, which becomes the secondary tropopause in middle to high latitudes. The association of the ozone and the thermal structure provides evidence for the physical significance of the subtropical tropopause break and the secondary tropopause. The core of the intruding layer is typically between 370 and 400 K potential temperature (∼15 km), but the vertical extent of the intrusion can impact ozone above 400 K, the lower boundary of the overworld. Two intrusion events over the continental United States in the spring of 2007 are analyzed to show the spatial extent and the temporal evolution of the intruding air mass. These examples demonstrate the effectiveness of potential temperature lapse rate, i.e., static stability, as a diagnostic for the intrusion event. Comparison with the potential vorticity field is made to show the complementarity of the two dynamical fields. The static stability diagnostic provides a tool to map out the horizontal extent of the intruding layer and to investigate its evolution. Furthermore, the diagnostic makes it possible to forecast the intrusion event for field studies.