Is a global warming signature emerging in the tropical Pacific?

• Published in: Geophysical research letters Vol. 39; no. 2
• Main Authors: Ashok, K., Sabin, T. P., Swapna, P., Murtugudde, R. G.
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 01.01.2012; American Geophysical Union; John Wiley & Sons, Inc
• Subjects: Atmospheric sciences; Climate change; Earth; Earth sciences; Earth, ocean, space; El Nino; El Niño; Exact sciences and technology; Geophysics; Global warming; impacts; La Nina; Oceans; Orthogonal functions; Physical oceanography; Signatures; Summer; Trends; Equatorial Pacific; Pacific Ocean; IS, Tropical Pacific; experimental studies; Teleconnection; models; trend-surface analysis; climate warming; Summer; Empirical orthogonal function; Temperature gradient; global warming; El Nino; global change; cooling; Boreal; La Nina; climate change
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2011GL050232

The tropical pacific experienced a hitherto‐unseen anomalous basinwide warming from May 2009 through April 2010 with the maximum warming to the east of the dateline, but for a weak anomalous cooling west of 140°E after early boreal fall. Our observed analysis and model experiments isolate the potential teleconnections from TP during the summer of 2009. Further, we show through an empirical orthogonal function analysis of the tropical Pacific SSTA that the anomalous conditions in TP during this period could have manifested as a canonical El Niño, but for a slowly intensifying background west–east gradient. This zonal SST gradient is subject to an increasing trend associated with global warming. A possible implication is that any further increase in global warming may result in more basinwide warm events in place of canonical El Niños, along with the occurrence of more intense La Niñas and El Niño Modokis. Key Points Basin‐wide warm event over tropical pacific during the boreal summer of 2009 Evolution of the tropical Pacific SST and potential role of global warming Global warming may result in more basin‐wide warm events