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Title: Decadal Variability of the Indian and Pacific Walker Cells since the 1960s: Do They Covary on Decadal Time Scales?

Authors:
 [1];  [2];  [2];  [3];  [1];  [4];  [5];  [6]
  1. Department of Atmospheric and Oceanic Sciences, University of Colorado Boulder, Boulder, Colorado
  2. Climate and Global Division, National Center for Atmospheric Research, Boulder, Colorado
  3. Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
  4. Laboratoire d’Océanographie: Expérimentation et Approches Numériques, IPSL, Sorbonne Universités/UPMC, IRD, CNRS, MNHN, Paris, France
  5. Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, Colorado
  6. Department of Civil Engineering, Jenderal Soedirman University, Purwokerto, Indonesia
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1394718
Grant/Contract Number:
FC02-97ER62402
Resource Type:
Journal Article: Published Article
Journal Name:
Journal of Climate
Additional Journal Information:
Journal Volume: 30; Journal Issue: 21; Related Information: CHORUS Timestamp: 2017-09-25 16:51:34; Journal ID: ISSN 0894-8755
Publisher:
American Meteorological Society
Country of Publication:
United States
Language:
English

Citation Formats

Han, Weiqing, Meehl, Gerald A., Hu, Aixue, Zheng, Jian, Kenigson, Jessica, Vialard, Jérôme, Rajagopalan, Balaji, and Yanto,. Decadal Variability of the Indian and Pacific Walker Cells since the 1960s: Do They Covary on Decadal Time Scales?. United States: N. p., 2017. Web. doi:10.1175/JCLI-D-16-0783.1.
Han, Weiqing, Meehl, Gerald A., Hu, Aixue, Zheng, Jian, Kenigson, Jessica, Vialard, Jérôme, Rajagopalan, Balaji, & Yanto,. Decadal Variability of the Indian and Pacific Walker Cells since the 1960s: Do They Covary on Decadal Time Scales?. United States. doi:10.1175/JCLI-D-16-0783.1.
Han, Weiqing, Meehl, Gerald A., Hu, Aixue, Zheng, Jian, Kenigson, Jessica, Vialard, Jérôme, Rajagopalan, Balaji, and Yanto,. 2017. "Decadal Variability of the Indian and Pacific Walker Cells since the 1960s: Do They Covary on Decadal Time Scales?". United States. doi:10.1175/JCLI-D-16-0783.1.
@article{osti_1394718,
title = {Decadal Variability of the Indian and Pacific Walker Cells since the 1960s: Do They Covary on Decadal Time Scales?},
author = {Han, Weiqing and Meehl, Gerald A. and Hu, Aixue and Zheng, Jian and Kenigson, Jessica and Vialard, Jérôme and Rajagopalan, Balaji and Yanto,},
abstractNote = {},
doi = {10.1175/JCLI-D-16-0783.1},
journal = {Journal of Climate},
number = 21,
volume = 30,
place = {United States},
year = 2017,
month =
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on September 25, 2018
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  • Superimposed on a pronounced warming trend, the Indian Ocean (IO) sea surface temperatures (SSTs) also show considerable decadal variations that can cause regional climate oscillations around the IO. However, the mechanisms of the IO decadal variability remain unclear. Here we perform numerical experiments using a state-of-the-art, fully coupled climate model in which the external forcings with or without the observed SSTs in the tropical eastern Pacific Ocean (TEP) are applied for 1871–2012. Both the observed timing and magnitude of the IO decadal variations are well reproduced in those experiments with the TEP SSTs prescribed to observations. Although the external forcingsmore » account for most of the warming trend, the decadal variability in IO SSTs is dominated by internal variability that is induced by the TEP SSTs, especially the Inter-decadal Pacific Oscillation (IPO). The IPO weakens (enhances) the warming of the external forcings by about 50% over the IO during IPO’s cold (warm) phase, which contributes about 10% to the recent global warming hiatus since 1999. As a result, the decadal variability in IO SSTs is modulated by the IPO-induced atmospheric adjustment through changing surface heat fluxes, sea surface height and thermocline depth.« less
  • The cause of decadal climate variability over the North Pacific Ocean and North America is investigated by the analysis of data from a multidecadal integration with a state-of-the-art coupled ocean-atmosphere model and observations. About one-third of the low-frequency climate variability in the region of interest can be attributed to a cycle involving unstable air-sea interactions between the subtropical gyre circulation in the North Pacific and the Aleutian low-pressure system. The existence of this cycle provides a basis for long-range climate forecasting over the western United States at decadal time scales. 17 refs., 5 figs.
  • An abrupt change in the large-scale boreal winter circulation pattern over the North Pacific was observed during the mid-1970s. This paper presents a variety of observed data and model results to describe the climate shift, and to understand some of the links within the coupled climate system that produced, it. Five main findings are emphasized: (1) evidence of abrupt, simultaneous, and apparently related changes can be found in many fields and in many model results; the climate shift is not an artifact, (2) over the tropical Pacific the climate change represents a shift in the state of the coupled ocean-atmospheremore » system, some aspects of which resemble features associated with El Nino episodes. However, the shift in state is not well characterized as due to a change in the frequency of intensity of El Nino episodes; it is better described as a change in background mean state, (3) When forced with observed SSTs, both a very simple atmospheric model and a full general circulation model (GCM) qualitatively simulate aspects of the decadalscale shift over the tropical Pacific, (4) when forced with observed surface wind stress, two ocean models of the tropical Pacific, in which surface heat fluxes are parameterized as Newtonian damping, reproduce some aspects of the near-equatorial decadal SST signal. However, the models do not reproduce the large changes in SST observed at higher latitudes of the tropical Pacific. suggesting that altered surface heat fluxes dominated in producing these changes, and (5) an important new finding of this study is the success of a GCM in reproducing important aspects of the observed mid-1970s shift in winter northern hemisphere circulation. Comparative analyses of the observed and GCM simulated circulation suggest the altered patterns of tropical Pacific SST and convection were important in forcing the changes in the mid-latitude circulation, a finding corroborated by recent GCM experiments. 70 refs., 18 figs.« less
  • The dynamics and predictability of decadal climate variability over the North Pacific and North America are investigated by analyzing various observation datasets and the output of a state of the art coupled ocean-atmosphere general circulation model that was integrated for 125 years. Both the observations and model results support the picture that the decadal variability in the regional of interest is based on a cycle involving unstable ocean-atmosphere interactions over the North Pacific. The period of this cycle is of the order of a few decades. The cycle involves the two major circulation regimes in the North Pacific climate system,more » the subtropical ocean gyre, and the Aleutian low. 41 refs., 18 figs.« less