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 学术活动
美国夏威夷大学Bin Wang教授来我室进行学术交流
时间：2014-10-24 来源：
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美国夏威夷大学Bin Wang教授来我室进行学术交流并作学术报告“Understanding of essential dynamics of the Madden-Julian Oscillation (MJO) and Boreal Summer Intraseasonal Oscillation (BSISO)”。
Understanding the origin and perpetuation of the Madden-Julian Oscillation (MJO) has eluded scientists for decades. In this presentation, I shall first discuss the fundamental features of MJO and BSISO that request theoretical explanation. I shall then discuss physical processes that are involved in the MJO dynamics. A general theoretical framework and associated governing equations describing MJO dynamics is then proposed in an attempt to unify the existing theories.
I will present the frictionally coupled Kelvin-Rossby wave theory to explain the indispensable atmospheric dynamics of MJO by addressing the following questions: (a) Why does MJO possess a mixed Kelvin-Rossby wave structure in horizontal and a backward tilted vertical motion and moisture distribution in the vertical? (b) How can these two types of waves that propagate in opposite directions couple together with convection and select slow eastward propagation? (c) Why does the MJO have a planetary zonal circulation scale with a large scale convective complex?
More general theoretical frameworks are further formulated by extension of the said MJO model to include MJO interaction with synoptic scale disturbances and boreal summer mean states. Using these extension models, I will further discuss (d) How do upscale transfers of momentum, heat, and moisture could affect MJO skeleton dynamics? And (e) How the boreal summer mean state affect ISO? In particular, why the BSISO has maximum variability center in monsoon trough regions, and why the BSISO features a NW-SE titled rainfall band and moves northward in the monsoon regions.
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