DOI: 10.1175/JCLI-D-11-00332.1
Scopus记录号: 2-s2.0-84865728706
论文题名: The effect of the south pacific convergence zone on the termination of el niño events and the meridional asymmetry of ENSO
作者: McGregor S. ; Timmermann A. ; Schneider N. ; Stuecker M.F. ; England M.H.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2012
卷: 25, 期: 16 起始页码: 5566
结束页码: 5586
语种: 英语
Scopus关键词: Atmospheric circulation
; Ekman pumping
; EL Nino
; ENSO
; Ocean dynamics
; Climatology
; Ocean currents
; Salinity measurement
; Nickel compounds
; atmospheric circulation
; Ekman pumping
; El Nino
; El Nino-Southern Oscillation
; sea surface temperature
; temperature anomaly
; wind velocity
; Pacific Ocean
英文摘要: During large El Niño events the westerly wind response to the eastern equatorial Pacific sea surface temperature anomalies (SSTAs) shifts southward during boreal winter and early spring, reaching latitudes of 58-78S. The resulting meridional asymmetry, along with a related seasonal weakening of wind anomalies on the equator are key elements in the termination of strong El Niño events. Using an intermediate complexity atmosphere model it is demonstrated that these features result from a weakening of the climatological wind speeds south of the equator toward the end of the calendar year. The reduced climatological wind speeds, which are associated with the seasonal intensification of the South Pacific convergence zone (SPCZ), lead to anomalous boundary layer Ekman pumping and a reduced surface momentum damping of the combined boundary layer/lower-troposphere surface wind response to El Niño. This allows the associated zonal wind anomalies to shift south of the equator. Furthermore, using a linear shallow-water ocean model it is demonstrated that this southward wind shift plays a prominent role in changing zonal mean equatorial heat content and is solely responsible for establishing the meridional asymmetry of thermocline depth in the turnaround (recharge/discharge) phase of ENSO. This result calls into question the sole role of oceanic Rossby waves in the phase synchronized termination of El Niño events and suggests that the development of a realistic climatological SPCZ in December-February/March-May (DJF/MAM) is one of the key factors in the seasonal termination of strong El Niño events. © 2012 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/52284
Appears in Collections: 气候变化事实与影响
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作者单位: IPRC, SOEST, University of Hawaii at Manoa, Honolulu, HI, United States; Department of Meteorology, SOEST, University of Hawaii at Manoa, Honolulu, HI, United States; CCRC, University of New South Wales, Sydney, NSW, Australia; Climate Change Research Centre, University of New South Wales, Sydney, NSW, Australia
Recommended Citation:
McGregor S.,Timmermann A.,Schneider N.,et al. The effect of the south pacific convergence zone on the termination of el niño events and the meridional asymmetry of ENSO[J]. Journal of Climate,2012-01-01,25(16)