Increasing intensity of El Niño in the central equatorial Pacific

El Niño events can affect global weather patterns and have important socioeconomic consequences. Defining El Niño's characteristics is important for understanding its dynamics and its relation to climate change, as well as for predicting its impacts. Classical El Niños have their warmest anomalies in the eastern equatorial Pacific (EP). In the past two decades however, there have been frequent occurrences of a new type of El Niño that has its warmest anomalies in the central equatorial Pacific (CP). Using satellite observations, we show that the intensity of El Niño events in the CP region has almost doubled in the past three decades, with the strongest warming occurring in 2009-10. This trend is related to the increasing intensity as well as frequency of CP El Niño events. While sea surface temperatures (SSTs) in the CP region during El Niño years have been increasing, those during neutral and La Niña years have not. Therefore, the well-documented warming trend in the CP region, attributed by some to the effects of global warming on background SST, is primarily a result of more intense El Niño events.