DOI: 10.1175/JCLI-D-14-00573.1
Scopus记录号: 2-s2.0-84942057064
论文题名: Stationary eddies and the zonal asymmetry of net precipitation and ocean freshwater forcing
作者: Wills R.C. ; Schneider T.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2015
卷: 28, 期: 13 起始页码: 5115
结束页码: 5133
语种: 英语
Scopus关键词: Atmospheric humidity
; Budget control
; Oceanography
; Water
; Horizontal advection
; Northern Hemispheres
; Overturning circulation
; Regional differences
; Sea surface salinity
; Spatial variability
; Specific humidity
; Water availability
; Surface waters
; atmospheric moisture
; climate forcing
; Ekman pumping
; precipitation (climatology)
; salinity
; spatial variation
; transport process
; troposphere
; vorticity
; water vapor
; Atlantic Ocean
; Atlantic Ocean (North)
; Pacific Ocean
; Pacific Ocean (North)
英文摘要: Transport of water vapor in the atmosphere generates substantial spatial variability of net precipitation (precipitation minus evaporation). Over half of the total spatial variability in annual-mean net precipitation is accounted for by deviations from the zonal mean. Over land, these regional differences determine differences in surface water availability. Over oceans, they account, for example, for the Pacific- Atlantic difference in sea surface salinity, with implications for the deep overturning circulation. This study analyzes the atmosphericwater budget in reanalyses from ERA-Interim and MERRA, to investigate which physical balances lead to zonal variation in net precipitation. It is found that the leading-order contribution is zonal variation in stationary-eddy vertical motion. Transient eddies modify the pattern of zonally anomalous net precipitation by moving moisture from the subtropical and tropical oceans onto land and poleward across the Northern Hemisphere storm tracks. Zonal variation in specific humidity and stationary-eddy horizontal advection play a secondary role. The dynamics leading to net precipitation via vertical motion in stationary eddies can be understood from a lowertropospheric vorticity budget. The large-scale variations of vertical motion are primarily described by Sverdrup balance and Ekman pumping, with some modification by transient eddies. These results suggest that it is important to understand changes in stationary eddies and their influence on the zonal variation of transient eddy fluxes, in order to understand regional changes in net precipitation. They highlight the relative importance of different atmospheric mechanisms for the freshwater forcing of the North Pacific and North Atlantic. © 2015 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/50874
Appears in Collections: 气候变化事实与影响
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作者单位: California Institute of Technology, Pasadena, CA, United States; ETH Zurich, Zurich, Switzerland
Recommended Citation:
Wills R.C.,Schneider T.. Stationary eddies and the zonal asymmetry of net precipitation and ocean freshwater forcing[J]. Journal of Climate,2015-01-01,28(13)