DOI: 10.1175/JCLI-D-16-0204.1
Scopus记录号: 2-s2.0-85000956492
论文题名: The impact of the Asian summer monsoon circulation on the tropopause
作者: Wu Y. ; Shaw T.A.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2016
卷: 29, 期: 24 起始页码: 8689
结束页码: 8701
语种: 英语
Scopus关键词: Atmospheric pressure
; Atmospheric temperature
; Atmospheric thermodynamics
; Heating
; Mechanical waves
; Moisture
; Oceanography
; Surface waters
; Temperature
; Thermodynamics
; Vorticity
; Anticyclones
; Atmospheric circulation
; Monsoons
; Potential vorticity
; Stationary waves
; Clouds
英文摘要: Previous studies have identified two important features of summertime thermodynamics: 1) a significant correlation between the low-level distribution of equivalent potential temperature θe and the potential temperature θ of the extratropical tropopause and 2) a northwestward shift of the maximum tropopause θ relative to the maximum low-level θe. Here, the authors hypothesize these two features occur because of the Asian monsoon circulation. The hypothesis is examined using a set of idealized prescribed sea surface temperature (SST) aquaplanet simulations. Simulations with a zonally symmetric background climate exhibit a weak moisture-tropopause correlation. A significant correlation and northwestward shift occurs when a zonal wave-1 SST perturbation is introduced in the Northern Hemisphere subtropics. The equivalent zonal-mean subtropical warming does not produce a significant correlation. A mechanism is proposed to explain the moisture-tropopause connection that involves the circulation response to zonally asymmetric surface heating and its impact on the tropopause defined by the 2-potential-vorticity-unit (PVU; 1 PVU = 10-6 K kg-1 m2 s-1) surface. While the circulation response to diabatic heating is well known, here the focus is on the implications for the tropopause. Consistent with previous research, surface heating increases the low-level θe and produces low-level convergence and a cyclonic circulation. The low-level convergence is coupled with upper-level divergence via convection and produces an upper-level anticyclonic circulation consistent with Sverdrup balance. The anticyclonic vorticity lowers the PV northwest of the surface heating via Rossby wave dynamics. The decreased PV leads to a northwestward shift of the 2-PVU surface on fixed pressure levels. The θ value to the northwest of the surface heating is higher, and consequently the maximum tropopause θ increases. © 2016 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/50291
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN, United States; Department of the Geophysical Sciences, University of Chicago, Chicago, IL, United States
Recommended Citation:
Wu Y.,Shaw T.A.. The impact of the Asian summer monsoon circulation on the tropopause[J]. Journal of Climate,2016-01-01,29(24)