DOI: 10.1007/s00382-013-1906-6
Scopus记录号: 2-s2.0-84902012437
论文题名: Pacific interdecadal variability driven by tropical-extratropical interactions
作者: Farneti R. ; Molteni F. ; Kucharski F.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2014
卷: 42, 期: 2017-11-12 起始页码: 3337
结束页码: 3355
语种: 英语
英文关键词: ENSO
; Interdecadal climate variability
; Teleconnections
; Tropical-extratropical interactions
英文摘要: Interactions between the tropical and subtropical northern Pacific at decadal time scales are examined using uncoupled oceanic and atmospheric simulations. An atmospheric model is forced with observed Pacific sea surface temperatures (SST) decadal anomalies, computed as the difference between the 2000-2009 and the 1990-1999 period. The resulting pattern has negative SST anomalies at the equator, with a global pattern reminiscent of the Pacific decadal oscillation. The tropical SST anomalies are responsible for driving a weakening of the Hadley cell and atmospheric meridional heat transport. The atmosphere is then shown to produce a significant response in the subtropics, with wind-stress-curl anomalies having the opposite sign from the climatological mean, consistent with a weakening of the oceanic subtropical gyre (STG). A global ocean model is then forced with the decadal anomalies from the atmospheric model. In the North Pacific, the shallow subtropical cell (STC) spins down and the meridional heat transport is reduced, resulting in positive tropical SST anomalies. The final tropical response is reached after the first 10 years of the experiment, consistent with the Rossby-wave adjustment time for both the STG and the STC. The STC provides the connection between subtropical wind stress anomalies and tropical SSTs. In fact, targeted simulations show the importance of off-equatorial wind stress anomalies in driving the oceanic response, whereas anomalous tropical winds have no role in the SST signal reversal. We further explore the connection between STG, STC and tropical SST with the help of an idealized model. We argue that, in our models, tropical SST decadal variability stems from the forcing of the Pacific subtropical gyre through the atmospheric response to ENSO. The resulting Ekman pumping anomaly alters the STC and oceanic heat transport, providing a negative feedback on the SST. We thus suggest that extratropical atmospheric responses to tropical forcing have feedbacks onto the ocean dynamics that lead to a time-delayed response of the tropical oceans, giving rise to a possible mechanism for multidecadal ocean-atmosphere coupled variability. © 2013 Springer-Verlag Berlin Heidelberg. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/54535
Appears in Collections: 过去全球变化的重建
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作者单位: Earth System Physics Section, The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34014 Trieste, Italy; European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom
Recommended Citation:
Farneti R.,Molteni F.,Kucharski F.. Pacific interdecadal variability driven by tropical-extratropical interactions[J]. Climate Dynamics,2014-01-01,42(2017-11-12)