Large-scale atmospheric dynamics
Large-scale atmospheric dynamics
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DOI：
10.1007/3-540-37722-0_9
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
B. Hoskins;Bin Wang
中科院分区：
文献类型：
--
作者：
B. Hoskins;Bin Wang
Monsoons are a response of the coupled atmosphere±ocean±land system to annual variation of solar radiation forcing. Physical processes governing monsoon climate involve not only atmospheric dynamical processes but also extremely complex interactions among the atmosphere, ocean, and land surface processes. This chapter deals with atmospheric internal dynamical processes that are fundamental to understanding large-scale monsoon circulation. Even with a specific focus on the large-scale monsoon dynamics, choice of topics for a concise chapter remains a challenge, because the dynamics of the Asian monsoon involves nearly all aspects of tropical dynamics and climate dynamics. Two previous monsoon books edited by Fein and Stephens (1987) and Chang and Krishnamurti (1987) provided a number of chapters that are very useful for understanding the basic mechanisms of the monsoon, in particular, the chapters written by Webster (1987) and Young (1987). Our present chapters are built on, and complementary to, these previous works with emphasis on more advanced dynamical aspects relevant to the Asian monsoon and the progress that has been made during the last two decades. This chapter begins with a brief review of the properties of equatorial wave motions (Section 9.2) and how the tropical atmosphere responds to given idealized heating patterns (Section 9.3). The subsequent Sections 9.4 through 9.6 discuss mechanisms that are pertinent to comprehend the major Asian monsoon circulation systems, especially during summer when the Asian monsoon is a dominant feature of the global atmospheric circulation. The major circulation features of the lower troposphere include the continental monsoon lows (and the monsoon troughs) and the oceanic subtropical anticyclones, and the cross-equatorial Somalia jet. Above and to the north of the monsoon trough is located a huge anticyclonic circulation called the Tibetan High. The clockwise flow around this anticyclone contains an easterly jet stream in its southern flank called tropical easterly jet. In
