Graphical Abstract

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Seiki, A., M. Nagura, T. Hasegawa, and K. Yoneyama, 2015: Seasonal onset of the Madden-Julian Oscillation and its relation to the southeastern Indian Ocean cooling. J. Meteor. Soc. Japan, 93A, 139-156.
Special Edition on Contributions to Asia Oceania Atmospheric Sciences
https://doi.org/10.2151/jmsj.2015-047  Graphical Abstract with highlights

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Highlights:

• The relation among sea surface temperature (SST) cooling in the southeastern Indian Ocean (SEIO), oceanic Rossby waves, and the seasonal onset of the Madden–Julian Oscillation (MJO) is examined for the period 1993–2012.
• Positive SST anomalies migrate concurrently with the downwelling Rossby waves but are followed by a wide-spread cold SST area in the SEIO from boreal summer to fall (Fig. 1). Whereas the SEIO cooling tends to persist for a longer period until November during positive Indian Ocean Dipole (IOD) and/or El Niño years, it occurs irrespective of the IOD.
• Convection related to the MJO events during boreal winter propagates from the Indian Ocean to the Pacific only after the SEIO cooling is terminated (Fig. 2). The SEIO cooling tends to prevent intraseasonal convection from propagating eastward to the Pacific via excitation of the local circulations over the eastern Indian Ocean and the tropical western Pacific.