A New Phenomenon is Found in the Tropical Pacific
The El Niño Modoki
El Niño Modoki is a coupled ocean-atmosphere phenomenon in the tropical Pacific. It is different from another coupled phenomenon in the tropical Pacific namely, El Niño. Conventional El Niño is characterized by strong anomalous warming in the eastern equatorial Pacific (see figure below). Whereas, El Niño Modoki is associated with strong anomalous warming in the central tropical Pacific and cooling in the eastern and western tropical Pacific (see figure below). Associated with this distinct warming and cooling patterns the teleconnections are very different from teleconnection patterns of the conventional El Niño. Hence, the new phenomenon is of interest to the climate community.
|Anomalous SST during El Niño||Anomalous SST during El Niño Modoki|
The name " El Niño Modoki " was first coined by Prof. Yamagata in various press releases. Researchers of the Climate Variations Research Program of Frontier Research Center for Global Change (FRCGC) lead by Prof. Yamagata documented this phenomenon for the first time. This phenomenon appears as second dominant mode of interannual variability in the tropical Pacific:
|First EOF mode of SSTA representing El Niño||Second EOF mode of SSTA representing El Niño Modoki|
El Niño Modoki Impacts
The El Niño Modoki phenomenon is characterized by the anomalously warm central equatorial Pacific flanked by anomalously cool regions in both west and east. Such zonal SST gradients result in anomalous two-cell Walker Circulation over the tropical Pacific, with a wet region in the central Pacific.
|Skin Temperature during El Niño||Skin Temperature during El Niño Modoki|
|Rainfall during El Niño||Rainfall during El Niño Modoki|
The El Niño Modoki significantly influences regional climates in China, Japan and US.
|China, rainfall during El Niño||China, rainfall during El Niño Modoki|
|Japan, rainfall during El Niño||Japan, rainfall during El Niño Modoki|
|USA, rainfall during El Niño||USA, rainfall during El Niño Modoki|
|Evolution of the El Niño Modoki Index(EMI)|
|Pacific Ocean SST Anomaly and SST Distribution|
SST anomalies are shaded (red color is for warm anomalies and blue is for cold).
- Weng, H., K. Ashok, S. K. Behera, S. A. Rao, and T. Yamagata, 2007 : Impacts of recent El Niño Modoki on dry/wet condidions in the Pacific rim during boreal summer. Climate Dynamics, 29, 113-129. (pdf)
- Ashok, K., S. K. Behera, S. A. Rao, H. Weng, and T. Yamagata, 2007 : El Niño Modoki and its possible teleconnection. J. Geophys. Res., 112, C11007, doi:10.1029/2006JC003798. (JGR site)
- Weng, H., S. K. Behera, and T. Yamagata, 2009 : Anomalous winter climate conditions in the Pacific rim during recent El Niño Modoki and El Niño events. Climate Dynamics, 32, 663-674.
- Ashok, K., and T. Yamagata, 2009 : The El Niño with a difference. Nature. 461, 481-484. (Nature site)
- Weng, H., G. Wu, Y. Liu, S. K. Behera, and T. Yamagata, 2009 : Anomalous summer climate in China influenced by the tropical Indo-Pacific Oceans. Climate Dynamics. DOI 10.1007/s00382-009-0658-9.
- Ratnam J. V., S. K. Behera, Y. Masumoto, K. Takahashi and T. Yamagata, 2010 : Pacific Ocean origin for the 2009 Indian summer monsoon failure. Geophys. Res. Lett., 37, L07807, doi:10.1029/2010GL042798. (GRL site)
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