Role of internal variability in recent decadal to multidecadal tropical Pacific climate changes

Bordbar, Mohammad Hadi, Martin, Thomas, Latif, Mojib and Park, Wonsun (2017) Role of internal variability in recent decadal to multidecadal tropical Pacific climate changes Geophysical Research Letters, 44 (9). pp. 4246-4255. DOI 10.1002/2016GL072355.

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Abstract

While the Earth's surface has considerably warmed over the past two decades, the tropical Pacific has featured a cooling of sea surface temperatures in its eastern and central parts, which went along with an unprecedented strengthening of the equatorial trade winds, the surface component of the Pacific Walker Circulation (PWC). Previous studies show that this decadal trend in the trade winds is generally beyond the range of decadal trends simulated by climate models when forced by historical radiative forcing. There is still a debate on the origin of and the potential role that internal variability may have played in the recent decadal surface wind trend. Using a number of long control (unforced) integrations of global climate models and several observational data sets, we address the question as to whether the recent decadal to multidecadal trends are robustly classified as an unusual event or the persistent response to external forcing. The observed trends in the tropical Pacific surface climate are still within the range of the long-term internal variability spanned by the models but represent an extreme realization of this variability. Thus, the recent observed decadal trends in the tropical Pacific, though highly unusual, could be of natural origin. We note that the long-term trends in the selected PWC indices exhibit a large observational uncertainty, even hindering definitive statements about the sign of the trends.

Document Type: Article
Keywords: Pacific Walker Circulation; tropical Pacific climate change
Research affiliation: OceanRep > The Future Ocean - Cluster of Excellence
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-ME Maritime Meteorology
OceanRep > The Future Ocean - Cluster of Excellence > FO-R11
Refereed: Yes
DOI etc.: 10.1002/2016GL072355
ISSN: 0094-8276
Projects: PREFACE, SPACES, SACCUS, RACE, Future Ocean
Date Deposited: 12 May 2017 09:30
Last Modified: 19 Dec 2017 12:48
URI: http://eprints.uni-kiel.de/id/eprint/37968

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