Two different regimes of anomalous walker circulation over the Indian and pacific oceans before and after the late 1970s

Ryuichi Kawamura, Hiromitsu Aruga, Tomonori Matsuura, Satoshi Iizuka

Research output: Chapter in Book/Report/Conference proceedingChapter

3 Citations (Scopus)

Abstract

Using the National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis data aided by a coupled ocean-atmosphere model, we investigated two different regimes of anomalous Walker circulation system over the Pacific and Indian Oceans before and after a climate shift, which occurred in the late 1970s. During the period before the climate shift, an upper-level velocity potential anomaly systematically moves eastward from the tropical Indian Ocean to the warm pool region of the western Pacific during the growth phase of El Niño-Southern Oscillation (ENSO). In the meantime, the activities of South Asian and Australian summer monsoon systems are directly affected by the evolution of the anomalous Walker circulation. During the period after the climate shift, in contrast, an upperlevel velocity potential anomaly in the vicinity of the Philippine Sea and maritime continent is observed to expand westward into the northern Indian Ocean and South Asia during the decay phase of ENSO. This feature is identified with a major precursory signal of an anomalous South Asian summer monsoon in the preceding spring. The model captures a systematic eastward propagation similar to that observed prior to the late 1970s, but fails to reproduce the westward extension of the velocity potential anomaly observed to prevail after the late 1970s. The model results suggest that the cross-basin connection between the two oceans is a prerequisite for the turnabout of ENSO prior to the climate shift, in terms of the occurrence of westerly wind bursts.

Original languageEnglish
Title of host publicationEarth?s Climate
Subtitle of host publicationThe Ocean-Atmosphere Interaction, 2004
EditorsS.P. Xie, J.A. Carton, C. Wang
PublisherBlackwell Publishing Ltd.
Pages365-377
Number of pages13
ISBN (Electronic)9781118665947
ISBN (Print)9780875904122
DOIs
Publication statusPublished - Jan 1 2004

Publication series

NameGeophysical Monograph Series
Volume147
ISSN (Print)0065-8448
ISSN (Electronic)2328-8779

Fingerprint

Walker circulation
Indian Ocean
Pacific Ocean
Southern Oscillation
climate
monsoons
shift
ocean
anomalies
anomaly
summer
oceans
monsoon
Philippines
warm pool
continents
westerly
bursts
occurrences
atmospheres

All Science Journal Classification (ASJC) codes

  • Geophysics

Cite this

Kawamura, R., Aruga, H., Matsuura, T., & Iizuka, S. (2004). Two different regimes of anomalous walker circulation over the Indian and pacific oceans before and after the late 1970s. In S. P. Xie, J. A. Carton, & C. Wang (Eds.), Earth?s Climate: The Ocean-Atmosphere Interaction, 2004 (pp. 365-377). (Geophysical Monograph Series; Vol. 147). Blackwell Publishing Ltd.. https://doi.org/10.1029/147GM20

Two different regimes of anomalous walker circulation over the Indian and pacific oceans before and after the late 1970s. / Kawamura, Ryuichi; Aruga, Hiromitsu; Matsuura, Tomonori; Iizuka, Satoshi.

Earth?s Climate: The Ocean-Atmosphere Interaction, 2004. ed. / S.P. Xie; J.A. Carton; C. Wang. Blackwell Publishing Ltd., 2004. p. 365-377 (Geophysical Monograph Series; Vol. 147).

Research output: Chapter in Book/Report/Conference proceedingChapter

Kawamura, R, Aruga, H, Matsuura, T & Iizuka, S 2004, Two different regimes of anomalous walker circulation over the Indian and pacific oceans before and after the late 1970s. in SP Xie, JA Carton & C Wang (eds), Earth?s Climate: The Ocean-Atmosphere Interaction, 2004. Geophysical Monograph Series, vol. 147, Blackwell Publishing Ltd., pp. 365-377. https://doi.org/10.1029/147GM20
Kawamura R, Aruga H, Matsuura T, Iizuka S. Two different regimes of anomalous walker circulation over the Indian and pacific oceans before and after the late 1970s. In Xie SP, Carton JA, Wang C, editors, Earth?s Climate: The Ocean-Atmosphere Interaction, 2004. Blackwell Publishing Ltd. 2004. p. 365-377. (Geophysical Monograph Series). https://doi.org/10.1029/147GM20
Kawamura, Ryuichi ; Aruga, Hiromitsu ; Matsuura, Tomonori ; Iizuka, Satoshi. / Two different regimes of anomalous walker circulation over the Indian and pacific oceans before and after the late 1970s. Earth?s Climate: The Ocean-Atmosphere Interaction, 2004. editor / S.P. Xie ; J.A. Carton ; C. Wang. Blackwell Publishing Ltd., 2004. pp. 365-377 (Geophysical Monograph Series).
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