>MONTHLY SST ANOMALY MAP
The map of Global OI.v2 SST anomalies for September 2010 downloaded from the NOMADS website is shown below. The central equatorial Pacific SST anomalies are continuing their decline associated with the La Niña.
September 2010 SST Anomalies Map (Global SST Anomaly = +0.19 deg C)
A NOTE ABOUT GLOBAL SST ANOMALIES
Global SST anomalies, based on the weekly Reynolds OI.v2 data, dropped 0.13 deg C over the past two weeks. This can be seen in the graph of weekly Global SST anomalies. The present value is 0.1 deg C.
Weekly Global SST Anomalies
The next graph is a comparison of the global SST anomalies for 2010 compared to 1988, 1998, and 2007. Those were other transition years from El Niño to La Niña. In the graph, the data has been shifted so that the first weeks were all zeroed. The current transition is well within the range of past transitions from El Niño to La Niña.
Comparison Of Transitions From El Niño To La Nina
Monthly NINO3.4 SST anomalies are well below the -0.5 deg C threshold of a La Niña. The Monthly NINO3.4 SST Anomaly is -1.57 deg C. Weekly data has dropped below -1.8 deg C (-1.84 deg C).
Global SST anomalies dropped this month, -0.028 deg C. There were decline in both the Southern Hemisphere (-0.044 deg C) and the Northern Hemisphere
(-0.007 deg C), though the drop in the Northern Hemisphere was so small it’s basically unchanged.
Monthly Change = -0.028 deg C
NINO3.4 SST Anomaly
Monthly Change = -0.36 deg C
EAST INDIAN-WEST PACIFIC
The SST anomalies in the East Indian and West Pacific made a slight rise this month. Will they continue to rise, noticeably, in response to the La Niña as they have in the past?
I’ve added this dataset in an attempt to draw attention to what appears to be the upward step responses. Using the 1986/87/88 and 1997/98 El Niño events as references, East Indian-West Pacific SST Anomalies peak about 7 to 9 months after the peak of the NINO3.4 SST anomalies, so we shouldn’t expect any visible sign of a step change for almost 18 to 24 months. We’ll just have to watch and see.
East Indian-West Pacific (60S-65N, 80E-180)
Monthly Change = +0.028 deg C
Further information on the upward “step changes” that result from strong El Niño events, refer to my posts from a year ago 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 for the discussions of the processes that cause the rise, refer to More Detail On The Multiyear Aftereffects Of ENSO – Part 2 – La Niña Events Recharge The Heat Released By El Niño Events AND…During Major Traditional ENSO Events, Warm Water Is Redistributed Via Ocean Currents -AND- More Detail On The Multiyear Aftereffects Of ENSO – Part 3 – East Indian & West Pacific Oceans Can Warm In Response To Both El Niño & La Niña Events
The animations included in post La Niña Is Not The Opposite Of El Niño – The Videos further help explain the reasons why East Indian and West Pacific SST anomalies can rise in response to both El Niño and La Niña events.
NOTE ABOUT THE DATA
The MONTHLY graphs illustrate raw monthly OI.v2 SST anomaly data from November 1981 to September 2010.
MONTHLY INDIVIDUAL OCEAN AND HEMISPHERIC SST UPDATES
Monthly Change = -0.007 deg C
Monthly Change = -0.044 deg C
North Atlantic (0 to 75N, 78W to 10E)
Monthly Change = -0.059 deg C
South Atlantic (0 to 60S, 70W to 20E)
Monthly Change = -0.064 deg C
Note: I discussed the upward shift in the South Atlantic SST anomalies in the post The 2009/10 Warming Of The South Atlantic.
North Pacific (0 to 65N, 100 to 270E, where 270E=90W)
Monthly Change = +0.054 Deg C
South Pacific (0 to 60S, 145 to 290E, where 290E=70W)
Monthly Change = -0.071 deg C
Indian Ocean (30N to 60S, 20 to 145E)
Monthly Change = -0.011 deg C
Arctic Ocean (65 to 90N)
Monthly Change = +0.178 deg C
Southern Ocean (60 to 90S)
Monthly Change = +0.024 deg C
WEEKLY NINO3.4 SST ANOMALIES
The weekly NINO3.4 SST anomaly data illustrate OI.v2 data centered on Wednesdays. The latest weekly NINO3.4 SST anomalies are -1.84 deg C.
Weekly NINO3.4 (5S-5N, 170W-120W)
The Optimally Interpolated Sea Surface Temperature Data (OISST) are available through the NOAA National Operational Model Archive & Distribution System (NOMADS).