In this post, I’ve also added a comparison of the SST anomalies of the NINO3.4 and NINO1+2 regions since people have been interested in the recent warming of the eastern Pacific.
NINO3.4 SST anomalies for the week centered on May 18, 2011 show that central equatorial Pacific SST anomalies are well into ENSO-neutral temperatures. They’re at approximately -0.17 deg C.
NINO3.4 SST Anomalies – Short-Term
Weekly Global SST anomalies have been bouncing around near the same value for the past month. Four weeks ago in the Mid-April update, they were at +0.13 deg C. They’re the same value for the week centered on May 18, 2011.
Global SST Anomalies – Short-Term
This weekly Reynolds OI.v2 SST dataset begins in 1990. For the graphs above, I’ve started the data in 2004 to make the variations visible.
COMPARISON OF WEEKLY NINO3.4 & NINO1+2 REGION SST ANOMALIES
The following is a Central Pacific Ocean Sea Surface Temperature (SST) anomaly map for the week centered on Wednesday May 18, 2011. It shows ENSO-neutral conditions in the central equatorial Pacific, in the area known as the NINO3.4 region. As noted above, NINO3.4 SST anomalies are approximately -0.17 deg C. To the east, note the warming in the eastern equatorial Pacific, in the area known as the NINO1+2 region. SST anomalies there for the week centered on May 18thare about +0.47 deg C. The week before they were close to +0.9 deg C. Do elevated SST anomalies in the eastern equatorial Pacific indicate an El Niño event is coming?
Central Pacific SST Anomaly Map
Not necessarily. The next graph compares NINO3.4 and NINO1+2 SST anomalies. The NINO1+2 SST anomalies are volatile. They can rise well above 1.0 deg C during an ENSO-neutral year as defined by the NINO3.4 SST anomalies. They did so in 2001 and 2008. But in 2002 and 2006, the sharp rises in NINO1+2 SST anomalies did precede El Niño events.
Weekly NINO3.4 and NINO1+2 SST Anomalies
OI.v2 SST anomaly data is available through the NOAA NOMADS system: