Regional patterns of tropical indo-pacific climate change: Evidence of the walker circulation weakening

Hiroki Tokinaga, Shang Ping Xie, Axel Timmermann, Shayne McGregor, Tomomichi Ogata, Hisayuki Kubota, Yuko M. Okumura

研究成果: Contribution to journalArticle査読

103 被引用数 (Scopus)

抄録

Regional patterns of tropical Indo-Pacific climate change are investigated over the last six decades based on a synthesis of in situ observations and ocean model simulations, with a focus on physical consistency among sea surface temperature (SST), cloud, sea level pressure (SLP), surface wind, and subsurface ocean temperature. A newly developed bias-corrected surface wind dataset displays westerly trends over the western tropical Pacific and easterly trends over the tropical Indian Ocean, indicative of a slowdown of the Walker circulation. This pattern of wind change is consistent with that of observed SLP change showing positive trends over the Maritime Continent and negative trends over the central equatorial Pacific. Suppressed moisture convergence over the Maritime Continent is largely due to surface wind changes, contributing to observed decreases in marine cloudiness and land precipitation there. Furthermore, observed ocean mixed layer temperatures indicate a reduction in zonal contrast in the tropical Indo-Pacific characterized by larger warming in the tropical eastern Pacific and western Indian Ocean than in the tropical western Pacific and eastern Indian Ocean. Similar changes are successfully simulated by an ocean general circulation model forced with the bias-corrected wind stress. Whereas results from major SST reconstructions show no significant change in zonal gradient in the tropical Indo-Pacific, both bucket-sampled SSTs and nighttime marine air temperatures (NMAT) show a weakening of the zonal gradient consistent with the subsurface temperature changes. All these findings fromindependent observations provide robust evidence for ocean-atmosphere coupling associatedwith the reduction in theWalker circulation over the last six decades.

本文言語英語
ページ(範囲)1689-1710
ページ数22
ジャーナルJournal of Climate
25
5
DOI
出版ステータス出版済み - 3 2012
外部発表はい

All Science Journal Classification (ASJC) codes

  • 大気科学

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