In 2009–2010, record warming occurred in the South Pacific and western Antarctica. To document the oceanic and atmospheric conditions associated with the sea surface temperature anomalies, Lee et al. analyzed satellite and in situ observations.
The anomalous warming in the south central Pacific region began in September 2009 and reached a record high in December, around the same time that the 2009–2010 central Pacific El Niño peaked. The amplitude of the South Pacific warming was more than 5 times larger than the usual variability in the region and was substantially stronger than the concurrent El Niño. The spatial extent of the South Pacific warming was comparable to the size of the continental United States and was associated with an unusually strong and persistent high-pressure system.