>This mid-month update only includes the shorter-term NINO3.4 and global SST anomaly graphs; that is, the ones from January 2004 to present. There’s not much happening, other than both datasets appear to have reached their seasonal lows for this La Niña.
As noted in the November 2010 SST Anomaly Update, the global SST anomalies do not appear as though they will drop to the level they had reached during the 2007/08 La Niña, even if one were to account for the differences in NINO3.4 SST anomalies. This of course will be misrepresented by some people as additional proof of anthropogenic global warming.
But the reason the global SST anomalies have warmed in that time is due primarily to the fact that the East Indian and West Pacific Oceans (about 25% of the surface area of the global oceans) can warm in response to both El Niño and La Niña events. Refer to Can El Niño Events Explain All of the Global Warming Since 1976? – Part 1 and Can El Niño Events Explain All of the Global Warming Since 1976? – Part 2, and the video included in La Niña Is Not The Opposite Of El Niño – The Videos. In addition, the North Atlantic also remains at elevated levels during La Niña events in response to the ENSO-related warming of the Kuroshio-Oyashio Extension. This was discussed and illustrated in the recent post The ENSO-Related Variations In Kuroshio-Oyashio Extension (KOE) SST Anomalies And Their Impact On Northern Hemisphere Temperatures.
Keep in mind, the warm water released from below the surface of the Pacific Warm Pool doesn’t simply vanish at the end of the El Niño.
NINO3.4 SST anomalies for the week centered on December 15, 2010 show that central equatorial Pacific SST anomalies have risen slightly in the past two weeks after a small dip. In other words, they’ve apparently reached the low end of this La Niña and they’re simply varying slightly at the seasonal La Niña level. They’re at approximately -1.4 deg C.
NINO3.4 SST Anomalies – Short-Term
Weekly Global SST anomalies may have reached their seasonal low. They are presently at +0.1 deg C.
Global SST Anomalies – Short-Term
OI.v2 SST anomaly data is available through the NOAA NOMADS system: