热带平流层与对流层之间相互作用的研究进展

ADVANCES IN INTERACTIONS BETWEEN TROPICAL STRATOSPHERE AND TROPOSPHERE

以热带平流层和对流层大气中的准两年振荡和ENSO现象,以及热带平流层和对流层交换(STE)过程为主轴,介绍了热带平流层和对流层大气相互作用方面的一些研究进展。众多的研究结果表明,平流层准两年振荡(QBO)和对流层准两年振荡(TBO)存在潜在联系,但二者之间相互作用的物理机制还不是很清晰。QBO对平流层大气中化学成分的空间分布具有显著的影响,但其中的化学-辐射-动力反馈作用目前还未得到充分的研究。以往的研究提供了ENSO影响热带平流层大气令人信服的证据,但影响的程度和范围还未形成一个共识,其中一个原因是平流层内的ENSO信号受到火山喷发和太阳活动的干扰。一些研究指出ENSO事件通过改变行星波的强度和传播对极地平流层大气产生影响,而平流层过程也会对ENSO的发生、发展和演变产生影响,但其可靠性需要进一步的确证。目前,一个较一致的结论是全球变暖会导致热带上涌增强,STE加快。然而,影响热带STE的大气过程较多,特别是季风系统和热带深对流系统对STE的贡献还需要深入的分析研究。

Studies on the interaction between the tropical stratosphere and troposphere that are mainly associated with the stratospheric quasi-biennial oscillation（QBO）,the El Nino–Southern Oscillation（ENSO） in the troposphere,and the stratosphere troposphere exchange（STE） are reviewed in this paper.Many investigations showed that there exits a relation between QBO and tropospheric quasi-biennial oscillation（TBO）,but the underlying physical mechanisms are still unclear.The QBO has a significant impact on the tracer distributions in the atmosphere,but associated interactions between chemistry,radiation and dynamics have not been fully investigated.Previous examinations provided convincing evidence that ENSO can affect tropical lower stratosphere,but the extent of the effect is still a subject of debate.One possible reason is that ENSO signals in the lower stratosphere can be contaminated by the solar activities and volcano eruptions.In some studies,it is pointed out that ENSO can significantly affect the polar stratosphere,and stratospheric processes also have an impact on the development of ENSO.However,the robustness of this conclusion needs further verification.A more consistent conclusion obtained from previous studies is that global warming can enhance tropical upwelling and intensify the Brewer-Dobson circulation and thereby accelerate tropical STE.However,there are quite a few atmospheric processes which are involved in the tropical STE.The contributions of monsoon and tropical deep convective activities to the STE are,in particular,worthy further investigation.