DOI: 10.1002/jgrd.50848
论文题名: Tropospheric SF<inf>6</inf>: Age of air from the Northern Hemisphere midlatitude surface
作者: Waugh D.W. ; Crotwell A.M. ; Dlugokencky E.J. ; Dutton G.S. ; Elkins J.W. ; Hall B.D. ; Hintsa E.J. ; Hurst D.F. ; Montzka S.A. ; Mondeel D.J. ; Moore F.L. ; Nance J.D. ; Ray E.A. ; Steenrod S.D. ; Strahan S.E. ; Sweeney C.
刊名: Journal of Geophysical Research Atmospheres
ISSN: 21698996
出版年: 2013
卷: 118, 期: 19 起始页码: 11429
结束页码: 11441
语种: 英语
英文关键词: transport
; troposphere
Scopus关键词: Aircraft exhibitions
; Tropics
; Troposphere
; Aircraft measurement
; Fundamental properties
; Interannual variation
; Meridional gradients
; Northern Hemispheres
; Spatial and temporal variation
; transport
; Sulfur hexafluoride
; age determination
; airborne survey
; atmospheric convection
; atmospheric modeling
; atmospheric transport
; midlatitude environment
; mixing ratio
; Northern Hemisphere
; seasonal variation
; seasonality
; Southern Hemisphere
; surface layer
; troposphere
英文摘要: Observations of SF6 are used to quantify the mean time since air was in ("mean age" from) the Northern Hemisphere (NH) midlatitude surface layer. The mean age is a fundamental property of tropospheric transport that can be used in theoretical studies and used to evaluate transport in comprehensive models. Comparisons of simulated SF6 and an idealized clock tracer confirm that the time lag between the SF6 mixing ratio at a given location and the NH midlatitude surface provides an accurate estimate of the mean age. The ages calculated from surface SF6 measurements show large meridional gradients in the tropics but weak gradients in the extratropics, with near-zero ages at the surface north of 30°N and ages around 1.4 years south of 30°S. Aircraft measurements show weak vertical age gradients in the lower and middle troposphere, with only slight increases of age with height in the NH and slight decreases with height in the Southern Hemisphere. There are large seasonal variations in the age at tropical stations (annual amplitudes around 0.5-1.0 year), with younger ages during northern winter, but only weak seasonal variations at higher latitudes. The seasonality and interannual variations in the tropics and Southern Hemisphere are related to changes in locations of tropical convection. There is qualitative agreement, in both spatial and temporal variations, between the simulated ages and observations. The model ages tend to be older than observed, with differences of ~0.2 year in the Northern Hemisphere upper troposphere and throughout the Southern Hemisphere troposphere. Key Points SF6 quantifies mean time since air was in NH mid-latitude surface layer Surface SF6 age varies from near zero north of 30°N to 1.4 years south of 30°S SF6 age is useful for evaluating tropospheric transport in models ©2013. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/63248
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Department of Earth and Planetary Sciences, Johns Hopkins University, 320 Olin Hall, 3400 N. Charles St., Baltimore, MD 21218, United States; Earth System Research Laboratory, NOAA, Boulder CO, United States; Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder CO, United States; Goddard Earth Sciences and Technology Center, Universities Space Research Association, Columbia MD, United States
Recommended Citation:
Waugh D.W.,Crotwell A.M.,Dlugokencky E.J.,et al. Tropospheric SF<inf>6</inf>: Age of air from the Northern Hemisphere midlatitude surface[J]. Journal of Geophysical Research Atmospheres,2013-01-01,118(19)