The influence of different El Nino flavours on global average tempeature

Wednesday, 17 December 2014
Simon D Donner, University of British Columbia, Vancouver, BC, Canada and Sandra P Banholzer, Stantec Consulting, Vancouver, BC, Canada
The El Niño–Southern Oscillation is known to influence surface temperatures worldwide. El Niño conditions are thought to lead to anomalously warm global average surface temperature, absent other forcings. Recent research has identified distinct possible types or flavours of El Niño events, based on the location of peak sea surface temperature anomalies and other variables. Here we analyze the relationship between the type of El Niño event and the global surface average temperature anomaly, using three historical temperature data sets. Separating El Niño events into types or flavours reveals that the global average surface temperatures are anomalously warm during and after canonical eastern Pacific El Niño events or "super" El Ninos. However, the global average surface temperatures during and after central Pacific or "mixed" events, like the 2002-3 event, are not statistically distinct from that of neutral or other years. Historical analysis indicated that slowdowns in the rate of global surface warming since the late 1800s may be related to decadal variability in the frequency of different types of El Niño events.