Last year about this time, the El Niño-Southern Oscillations (ENSO) models from around the globe predicted ENSO-neutral to El Niño conditions for the 2011/12 ENSO season. But the two siblings (El Niño and La Niña) decided that it was La Niña’s turn to alter weather patterns globally. This year, the models are predicting the same as last year: Some are predicting El Niño conditions, while others are leaning to ENSO-neutral.
If it’s an El Niño, it’s possible global surface temperature anomalies would set a new record high next year in some of the products used to display that metric. If it’s not, global surface temperatures are not as likely to present new record highs. Record global surface temperature levels or lack thereof, of course, stimulate claims on both sides of the anthropogenic global warming debate and serve as a basis for discussions.
So, readers, which will it be for the upcoming ENSO season: an El Niño, ENSO-neutral conditions, or a back-to-back-to-back/three-peat/triple-dip La Niña?
Don’t ask me; I don’t make predictions. But I would like to see two possible outcomes that are discussed in the closing.
Here are some visual aids to help you soothsayers with your prognostications.
Figures 1, 2 and 3 show the ENSO model forecasts from April 23, 2012 and May 9, 2011. The 2012 forecasts are from the latest NOAA/CPC ENSO Diagnostic Discussion that I downloaded on Monday April 30th. The 2011 forecasts from May 2011 are from the same website but archived on the Wayback Machine. To save you some time searching, I’ve uploaded and stored the two NOAA pdf documents at my website here (2012) and here (2011). Keep in mind the forecasts blew it last year: there was a La Niña for the 2011/12 season.
Figure 1 (Click to enlarge)
Figure 2 (Click to enlarge)
Figure 3 (Click to enlarge)
Figure 4 shows the 2012 and 2011 subsurface temperature anomalies for the equatorial Pacific. There are elevated subsurface temperature anomalies present at depth in the western equatorial Pacific in both years, while the pocket of warmer-than-normal subsurface waters in the east was larger last year.
Figure 4 (Click to enlarge)
The Australia’s Bureau of Meteorology (BOM) Southern Oscillation Index (SOI) data from Jan 1982 to April 2012 is shown in Figure 5. With the SOI, El Niño events are the sustained negative spikes and the La Niña events are positive ones. The SOI is an ENSO index that represents the difference in sea level pressure between Tahiti and Darwin Australia. The BOM standardizes the data and then multiplies it by 10. The April 2012 value of -7.1 is of interest because as the BOM notes on their Glossary webpage for the SOI:
Sustained negative values of the SOI greater than −8 often indicate El Niño episodes. These negative values are usually accompanied by sustained warming of the central and eastern tropical Pacific Ocean, a decrease in the strength of the Pacific Trade Winds, and a reduction in winter and spring rainfall over much of eastern Australia and the Top End. You can read more about historical El Niño events and their effect on Australia in the Detailed analysis of past El Niño events.
Like the SOI, El Niño events in NOAA’s trade wind index for the western equatorial Pacific (5S-5N, 135E-180)appear as prolonged downward spikes and La Niña events show up as the opposite. This is an important index because the Pacific trade winds push sunlight-warmed water in the tropical Pacific to the west; the trade winds “hold” the warm water in the western Pacific Warm Pool, where it “piles up”; and it’s a relaxation of the trade winds that allows gravity to carry the warm water from the Pacific Warm Pool to the east during an El Niño. Unfortunately, as of today (May 2, 2012) NOAA has not yet released its trade wind index data for April 2012. And as of March 2012, the trade winds in the western equatorial Pacific were still elevated.
Figures 7 and 8 are preliminary April 2012 and weekly satellite-based (Reynolds OI.v2) sea surface temperature anomalies for the NINO3.4 region of the equatorial Pacific (5S-5N, 170W-120W). I’ve borrowed them from my PRELIMINARY April 2012 SST Anomaly Update. NINO3.4 sea surface temperature anomalies are a widely referenced ENSO index and are used in NOAA’s Oceanic NINO Index (ONI) data, though ONI is based on NOAA’s ERSST.v3b sea surface temperature dataset. Unlike the SOI and trade wind data, El Niño events show up as prolonged positive values and La Niña events appear as prolonged negative sea surface temperature anomalies. Both the weekly and monthly NINO3.4 sea surface temperature anomalies show the central equatorial Pacific sea surface temperatures approaching 0.0 deg C. But that also happened last year before the weak La Niña formed.
So what will it be?
Personally, I would prefer either a La Niña or a Super El Niño like the one that occurred in 1997/98. Why? I’d like to see what happens to North Atlantic sea surface temperature anomalies if there was a three-peat La Niña. Will that contribute to a downturn in the Atlantic Multidecadal Oscillation?
And with all of those ARGO buoys bobbing around in the Pacific, they would provide new insight into the multiyear aftereffects of a Super El Niño. Researchers could track the huge volume of leftover warm water that returns to the western tropical Pacific via a Rossby wave (at about 10N) . Where does all of that warm subsurface water go after it slams into Indonesia? Does it, as I suspect, reappear as secondary, central Pacific, El Niño Modoki events over the next 8 to 10 years? If so, what paths does it take? After the warm water has been returned to the west and carried poleward, how long does it release heat in the Kuroshio-Oyashio Extension and South Pacific Convergence Zone, as secondary effects of the super El Niño? How much of the warm water makes its way into the tropical Indian Ocean to influence climate there? Little questions.
INTERESTED IN LEARNING MORE ABOUT THE EL NIÑO-SOUTHERN OSCILLATION?
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 the ENSO 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.
All but the source of the sea surface temperature data are linked in the text of the post. The Reynolds (OI.v2) SST anomaly data is available through the NOAA NOMADS website:
I would hope that at some point you would entertain a lively discussion about what SST’s, El Nino, and La Nina are actually telling us about energy and the ocean-atmopshere heat exchanges, which are possibly important to discussions on longer-term climate change. SST’s in general say more about about how much energy is or isn’t leaving the ocean relative to long term averages. As you have long pointed out, we will usually see the heat that has left the ocean during the higher than average SST’s of an El Nino show up in higher tropospheric temperatures several months later. SST’s are just that– a good metric for showing us energy moving from ocean to atmosphere. For this reason, we often actually see overall ocean heat content decrease after a strong El Nino, and conversely, ENSO neutral or La Nina periods are often (but not always) periods when the overall ocean heat content will increase.
Scott Supak: WordPress now automatically sends your comments here to the spam filter. Thankfully, I don’t even have to bother moderating them anymore.
R. Gates says: “I would hope that at some point you would entertain a lively discussion about what SST’s, El Nino, and La Nina are actually telling us about energy and the ocean-atmopshere heat exchanges, which are possibly important to discussions on longer-term climate change.”
I enjoy lively discussions. The livelier the better.
R. Gates says: “As you have long pointed out, we will usually see the heat that has left the ocean during the higher than average SST’s of an El Nino show up in higher tropospheric temperatures several months later.”
That’s correct. Elevated tropical Pacific temperature anomalies during an El Nino raise lower troposphere temperature anomalies and they work their way eastward and toward the poles:
One of these days I’m going replace the East Indian-West Pacific SST anomalies with TLT data in the graph in that animation.
R. Gates says: “SST’s are just that– a good metric for showing us energy moving from ocean to atmosphere.”
During an El Nino, I’ll answer yes from the tropical Pacific, but not necessarily elsewhere. Consider this: During an El Nino, the trade winds over the tropical North Atlantic decrease in strength. Sea surface temperature anomalies in the tropical North Atlantic rise because it is releasing less heat to the atmosphere through evaporation (weaker trade winds -> less evaporation -> higher sst). Since that’s the case, shouldn’t tropical North Atlantic sea surface temperature AND Ocean Heat Content both be increasing in response to the El Nino? And shouldn’t that also happen elsewhere where teleconnections have similar effects on sea surface temperatures?
R. Gates says: “For this reason, we often actually see overall ocean heat content decrease after a strong El Nino, and conversely, ENSO neutral or La Nina periods are often (but not always) periods when the overall ocean heat content will increase.”
The losses in tropical Pacific OHC during an El Nino can outweigh the gains in other areas. But let me ask: What happens to the warm water in the eastern tropical Pacific that’s leftover from the El Nino? It’s not all “consumed” by the El Nino. It’s got to go somewhere. Rossby waves and ocean currents carry it back to the west and toward the poles, and that happens during the La Nina that follows the El Nino. The opposite does not occur after a La Nina for many reasons.
“During an El Nino, the trade winds over the tropical North Atlantic decrease in strength. Sea surface temperature anomalies in the tropical North Atlantic rise because it is releasing less heat to the atmosphere through evaporation (weaker trade winds -> less evaporation -> higher sst). Since that’s the case, shouldn’t tropical North Atlantic sea surface temperature AND Ocean Heat Content both be increasing in response to the El Nino? And shouldn’t that also happen elsewhere where teleconnections have similar effects on sea surface temperatures?”
The heat content of the Atlantic basin decreased greatly during the El Nino of 1997-1998, SST’s are not good predictors of overall ocean heat content, but better at predicting the direction of heat content changes as they indicate general trends of net heat flow out of the oceans…i.e. warmer than average SST’s indicate greater than average heat flow out of an ocean basin.
R.Gates says: “The heat content of the Atlantic basin decreased greatly during the El Nino of 1997-1998, SST’s are not good predictors of overall ocean heat content…”
Always keep in mind the topic of discussion, R. Gates. We’re discussing the SST and OHC anomalies of the tropical North Atlantic, not the North Atlantic basin. There’s about a 6- to 8-month lag between the rise in NINO3.4 SST anomalies and the rises in tropical North Atlantic SST Anomalies AND OHC anomalies (0-24N, 80W-20E) during the 1997/98 El Nino.
That’s a good point Bob. I’d love to see a chart comparing SST’s in various regions and globally against ocean heat content at various depths– 700m, 1500m, 2000m. You seem to be such a wizard with charts, and chance you could assist, or have you already done this?
R.Gates: Just this one about a year ago:
There’s no reason to look at anything below 700meters. The variability is at the top and the data is way too sparse at 1500meters and 2000meters, which is why the NODC presents it as 5-year average at 2000 meters.
Excellent job Bob. Lot’s a great data summarized there. I’ll be studying it for a while. Thanks!
A note: NOAA has furnished the Western Equatorial Pacific Trade Wind Index data for April. It’s about where we’d expect it for the current NINO3.4 SST anomalies:
While SSTs are a good metric of ocean/atmosphere heat flows. SSTs also measure relative heat gain/loss from solar insolation changes.
I am not aware of any systematic study differentiating these 2 processes.