DOI: 10.1175/JCLI-D-17-0645.1
Scopus记录号: 2-s2.0-85047064284
论文题名: How momentum coupling affects SST variance and large-scale Pacific climate variability in CESM
作者: Larson S.M. ; Vimont D.J. ; Clement A.C. ; Kirtman B.P.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2018
卷: 31, 期: 7 起始页码: 2927
结束页码: 2944
语种: 英语
英文关键词: Atmosphere-ocean interaction
; Climate models
; Ekman pumping/transport
; Pacific decadal oscillation
; Sea surface temperature
Scopus关键词: Atmospheric thermodynamics
; Buoyancy
; Climate change
; Climate models
; Momentum
; Surface waters
; Tropics
; Atmosphere-ocean interactions
; Climate variability
; Ekman pumping/transport
; Freshwater fluxes
; Ocean heat transport
; Pacific decadal oscillation
; Sea surface temperature (SST)
; Tropical forcing
; Oceanography
英文摘要: The contribution of buoyancy (thermal 1 freshwater fluxes) versus momentum (wind driven) coupling to SST variance in climate models is a longstanding question. Addressing this question has proven difficult because a gap in the model hierarchy exists between the fully coupled (momentum 1 buoyancy 1 ocean dynamics) and slab-mixed layer ocean coupled (thermal with no ocean dynamics) versions. The missing piece is a thermally coupled configuration that permits anomalous ocean heat transport convergence decoupled from the anomalous wind stress.Amechanically decoupled model configuration is provided to fill this gap and diagnose the impact of momentum coupling on SST variance in NCAR CESM. A major finding is that subtropical SST variance increases when momentum coupling is disengaged. An ''opposing flux hypothesis'' may explain why the subtropics (midlatitudes) experience increased (reduced) variance without momentum coupling. In a subtropical easterly wind regime, Ekman fluxes (Q'ek) oppose thermal fluxes (Q'th), such that when the air and sea are mechanically decoupled (Q'ek 50), Q'ek 1Q'th variance increases. As a result, SST variance increases. In a midlatitude westerly regime where Q'ek and Q'th typically reinforce each other, SST variance is reduced. Changes in mean surface winds with climate change could impact the Q'ek and Q'th covariance relationships. A by-product of mechanically decoupling the model is the absence of ENSO variability. The Pacific decadal oscillation operates without momentumcoupling or tropical forcing, although the pattern is modified with enhanced (reduced) variability in the subtropics (midlatitudes). Results show that Ekman fluxes are an important component to tropical, subtropical, and midlatitude SST variance. © 2018 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/111600
Appears in Collections: 气候减缓与适应
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作者单位: Atmospheric and Oceanic Sciences Department, University of Wisconsin-Madison, Madison, WI, United States; Nelson Institute Center for Climatic Research, University of Wisconsin-Madison, Madison, WI, United States; Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States
Recommended Citation:
Larson S.M.,Vimont D.J.,Clement A.C.,et al. How momentum coupling affects SST variance and large-scale Pacific climate variability in CESM[J]. Journal of Climate,2018-01-01,31(7)