DOI: 10.1007/s00382-012-1420-2
Scopus记录号: 2-s2.0-84874325299
论文题名: What controls phase-locking of ENSO to boreal winter in coupled GCMs?
作者: Ham Y.-G. ; Kug J.-S. ; Kim D. ; Kim Y.-H. ; Kim D.-H.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2013
卷: 40, 期: 2017-05-06 起始页码: 1551
结束页码: 1568
语种: 英语
英文关键词: CGCM
; CMIP3
; ENSO
; Seasonal locking
英文摘要: In this study, the phase-locking of El Nino Southern Oscillation (ENSO) in a coupled model with different physical parameter values is investigated. It is found that there is a dramatic change in ENSO phase-locking in response to a slight change in the Tokioka parameter, which is a minimum entrainment rate threshold in the cumulus parameterization. With a smaller Tokioka parameter, the model simulates ENSO peak in the boreal summer season rather than in the winter season as observed. It is revealed that the differences in climatological zonal sea surface temperature (SST) gradient and its associated mean state changes are crucial to determine the phase-locking of ENSO. In the simulations with smaller Tokioka parameter values, climatological zonal SST gradient during the boreal summer is excessively large, because the zonally-asymmetric SST change (i. e., SST increase is relatively smaller over the eastern Pacific) is maximum during the boreal summer when the eastern Pacific SST is the coolest of the year. The enhanced climatological zonal SST gradient in boreal summer reduces the convection over the eastern Pacific, which leads to a weakening of air-sea coupling strength. The minimum coupling strength during summer prevents SST anomalies from further development in the following season, which favors SST maximum during summer. In addition, enhanced zonal SST gradient and resultant thermocline shoaling over the eastern Pacific lead to excessive zonal advective feedback and thermocline feedback. Atmospheric damping is also weakened during boreal summer season. These changes due to feedback processes allow an excessive development of SST anomalies during the summer time, and lead to a summer peak of ENSO. The importance of basic state change for the ENSO phase-locking is also validated in a multi-model framework using the Coupled Model Intercomparison Project phase-3 archive. It is found that several of the climate models have the same problem in producing a summer peak of ENSO. Consistent with the simulations with different physical parameter values, these models have minimum air-sea coupling strength during the boreal summer season. Also, they have stronger climatological zonal SST gradient and shallower climatological thermocline depth over the eastern Pacific during the boreal summer season. © 2012 Springer-Verlag. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/54917
Appears in Collections: 过去全球变化的重建
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作者单位: Global Modeling and Assimilation Office, GSFC/NASA, Greenbelt, MD, United States; Goddard Earth Sciences Technology and Research Studies and Investigations, Universities Space Research Association, Greenbelt, MD, United States; Korea Ocean Research and Development Institute, Ansan, South Korea; Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, NY, United States; Department of Atmospheric Science, Yonsei University, Seoul, South Korea
Recommended Citation:
Ham Y.-G.,Kug J.-S.,Kim D.,et al. What controls phase-locking of ENSO to boreal winter in coupled GCMs?[J]. Climate Dynamics,2013-01-01,40(2017-05-06)