Weekly NINO3.4 region (5S-5N, 170W-120W) sea surface temperature anomalies (a commonly used index for the strength, frequency, and duration of El Niño and La Niña events) for 2012 are compared to those of the El Niño events since 1982, but to reduce the number of events, I’m only showing the ones that started from La Niña conditions. The evolution of the event this year does not appear to be anything extraordinary. NINO3.4 sea surface temperature anomalies are about the same level they were at during the development of the 2009/10 El Niño.
NINO3.4 Evolution Comparison
NINO1+2 region (10S-0, 90W-80W) sea surface temperature anomalies are continuing to cool. They had started out strong this year, leading some to believe this year’s El Niño would be an East Pacific event. Will they turn around?
NINO1+2 Evolution Comparison
Now back to your regularly scheduled program.
STANDARD OPENING PARAGRAPH
The July 2012 Reynolds OI.v2 Sea Surface Temperature (SST) data through the NOAA NOMADS website won’t be official until Monday, July 6th. Refer to the schedule on the NOAA Optimum Interpolation Sea Surface Temperature Analysis Frequently Asked Questionswebpage. The following are the preliminary Global and NINO3.4 SST anomalies for July 2012 that the NOMADS website prepares based on incomplete data for the month. I’ve also included the weekly data through the week centered on July 25, 2012, but I’ve shortened the span of the weekly data, starting it in January 2004, so that the variations can be seen.
PRELIMINARY MONTHLY DATA
Based on the preliminary data, monthly NINO3.4 SST anomalies are at +0.688 deg C well above the +0.5 deg C threshold of “official” El Niño conditions.
Monthly NINO3.4 SST Anomalies
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The preliminary global SST anomalies have rebounded quite a bit in the last month. They’re presently at +0.221 deg C.
Monthly Global SST Anomalies
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WEEKLY DATA
The weekly NINO3.4 SST anomalies for the week centered on July 25, 2012 are at +0.751 deg C.
Weekly NINO3.4 SST Anomalies
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Weekly Global SST Anomalies are continuing to wiggle their way warmer, a rise for a couple of weeks, followed by a drop the next, with the rises exceeding the drops. They are presently at +0.238 deg C.
Weekly Global SST Anomalies
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INTERESTED IN LEARNING MORE ABOUT THE EL NIÑO-SOUTHERN OSCILLATION?
I’m about 80% to 85% finished with my upcoming book about the climate phenomenon called El Niño-Southern Oscillation. The working title is Who Turned on the Heat? The subtitle is The Unsuspected Global Warming Culprit, El Niño-Southern Oscillation. I’m continuing to add chapters at the suggestions of readers and as I run through my old blog posts and find topics I’d like to add. These additions will make the book more complete and help to confirm for you my findings on the long-term effects of El Niño and La Niña events. The additions have pushed back the completion date. I’m hoping to publish in pdf and Amazon Kindle forms by the end of August. As it exists, there are 420 pages, 76,000+ words, and 304 illustrations. If a picture is worth a thousand words…
Can’t wait?
About one-quarter of my book If the IPCC was Selling Manmade Global Warming as a Product, Would the FTC Stop their deceptive Ads?, Section 6, is about the processes that are part of El Niño and La Niña events. Many of the discussions are rewordings (expansions and simplifications) of my posts here at Climate Observations, so you could save a few bucks and read dozens of posts. But the book provides a single resource and reference for you and includes a very basic, well-illustrated introduction to El Niño, La Niña, and ENSO-neutral conditions written in simple terms. Included in that section are discussions of how La Niña events are not the opposite of El Niño events and how and why certain parts of the global oceans warm in response to certain El Niño AND to the La Niña events that follow them. The El Niño-Southern Oscillation is a marvelous process Mother Nature has devised to enhance or slow the distribution of heat from the tropics to the poles. It is process that naturally varies in intensity, and due to those variations, it is capable of warming or cooling global temperatures over multiyear and multidecadal periods. The individual chapter titles of Section 6 will give you an idea of the topics discussed. See pages 9 and 10 of the introduction, table of contents, and closing of my book in pdf form here.
SOURCES
The Sea Surface Temperature anomaly data used in this post is available through the NOAA NOMADS website:
http://nomad1.ncep.noaa.gov/cgi-bin/pdisp_sst.sh
or:
Bob Tisdale - Climate Observations 
I’ve just commented in the WUWT Dr Spencer thread that there is a clear NH seasonality in the temperature anomaly, in recent years. Up in summer, down in winter. I see the same pattern in the global SSTs.
I think this dates to around 1998/2000, but need to confirm this.
Philip Bradley: Some of the seasonal component can result from the choice of base years:
The graph is from this post:
But I agree. The UAH TLT anomalies have been showing additional variability in recent years, and if memory serves me well, UAH is using 1981 to 2010 for base years,
Bob, the main point is that if we see seasonality differences in the anomaly, it means something has changed. There is some new effect at work ‘changing’ the climate, which is why I am interesting in dating when the change occured.
Philip Bradley: And my reply was intended to illustrate one of the possible reasons for the additional seasonal component.
I don’t see a reason for the seasonality in your post, but perhaps I’m missing something.
I know the anomaly is computed on the same time period. So the anomaly say for December in 2012 is the difference between that year and the average of Decembers in the baseline period.
If we are seeing seasonality in the signal, It means it didn’t exist in the baseline, or has increased from the baseline period. Which what you show in your figure 4, Use a later baseline and the seasonality decreases but is clearly still there. Which tells me the effect is getting stronger.
Your figure 4 also shows that it is strong in the Northern Pacific, which points to changes in Asian aerosols as the cause.
If so, the effect will be larger in the Western Pacific than in the Eastern Pacific.
Recently you asked me for a data based study showing the effect of aerosols on SSTs. It looks like you may have the data.
regards
Hi Bob,
Thanks for this, the comparison with previous el nino years is interesting. Shouldn’t the legend element “2012/13 through July 25” read ‘2011/12’?
Unless you know more about the future temperature evolution than you’re letting on? 😉
Philip Bradley says: “I don’t see a reason for the seasonality in your post, but perhaps I’m missing something.”
The seasonal component changes with time. To see this, pick a sea surface temperature dataset (not anomaly) such as ERSST.v3b or HADISST at the KNMI Climate Explorer. Use the North Pacific coordinates (0-65N, 100E-270E) for example. There’s lots of variability and there are numerous factors that contribute to those variations.
Select the period of 1982 to 2011 as the base years. The anomaly data from 1982 to 2011 will have less of a seasonal component that the data before 1982.
Next try 1951-1980 for base years. The anomaly data for 1951-1980 will have less of a seasonal component than the periods before and after it.
tallbloke says: “Thanks for this, the comparison with previous el nino years is interesting. Shouldn’t the legend element ‘2012/13 through July 25’ read ’2011/12′?”
Nope. The red curve starts the first week in January 2012, and the 55th week on the graph would be in January 2013.
Also, since ENSO events are phase locked with the seasonal cycle and start in one calendar year then end in the next, I always list both years. It reduces confusion.
Regards