DOI: 10.1175/JCLI-D-16-0044.1
Scopus记录号: 2-s2.0-84991210215
论文题名: Composite analysis of large-scale environments conducive to western Pacific polar/subtropical jet superposition
作者: Handlos Z.J. ; Martin J.E.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2016
卷: 29, 期: 19 起始页码: 7145
结束页码: 7165
语种: 英语
Scopus关键词: Clouds
; Digital storage
; Jets
; Troposphere
; Cold air
; East Asian winter monsoon
; Hadley circulation
; Northern Hemispheres
; Objective identification
; Potential vorticity
; Upper troposphere
; Winter/cool seasons
; Fighter aircraft
英文摘要: Although considerable research attention has been devoted to examination of the Northern Hemisphere polar and subtropical jet streams, relatively little has been directed toward understanding the circumstances that conspire to produce the relatively rare vertical superposition of these usually separate features. This study investigates the structure and evolution of large-scale environments associated with jet superposition events in the northwest Pacific. An objective identification scheme, using NCEP-NCAR Reanalysis 1 data, is employed to identify all jet superpositions in the western Pacific (30°-40°N, 135°-175°E) for boreal winters (DJF) between 1979/80 and 2009/10. The analysis reveals that environments conducive to western Pacific jet superposition share several large-scale features usually associated with East Asian winter monsoon (EAWM) northerly cold surges, including the presence of an enhanced Hadley cell-like circulation within the jet entrance region. It is further demonstrated that several EAWM indices are statistically significantly correlated with jet superposition frequency in the western Pacific. The life cycle of EAWM cold surges promotes interaction between tropical convection and internal jet dynamics. Low-potential vorticity (PV), high-θe air, appearing to be associated with anomalous convection in the western Pacific lower latitudes, is advected poleward toward the equatorward side of the jet in upper-tropospheric isentropic layers, resulting in anomalous anticyclonic wind shear that accelerates the jet. This, along with geostrophic cold air advection in the left jet entrance region that drives the polar tropopause downward through the jet core, promotes the development of the deep, vertical PV wall characteristic of superposed jets. A conceptual model synthesizing the results of this analysis is introduced. © 2016 American Meteorological Society. 资助项目: NSF, National Science Foundation
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/50025
Appears in Collections: 气候变化事实与影响
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作者单位: University of Wisconsin-Madison, Madison, WI, United States
Recommended Citation:
Handlos Z.J.,Martin J.E.. Composite analysis of large-scale environments conducive to western Pacific polar/subtropical jet superposition[J]. Journal of Climate,2016-01-01,29(19)