The cause of a record warm El Niño year? Leftovers

From AGU:

Leftover warm water in Pacific Ocean fueled massive El Niño

This is a comparison of the 2015 and 1997 El Niños, two of the strongest on record, in October of each respective year. Observations of sea surface heights and temperatures, as well as wind patterns, show surface waters cooling off in the Western Pacific and warming significantly in the tropical Eastern Pacific. CREDIT NASA's Earth Observatory.

elnino-compare

This is a comparison of the 2015 and 1997 El Niños, two of the strongest on record, in each respective year. Observations of sea surface heights and temperatures, as well as wind patterns, show surface waters cooling off in the Western Pacific and warming significantly in the tropical Eastern Pacific. CREDIT NASA’s Earth Observatory.

WASHINGTON, DC — A new study provides insight into how the current El Niño, one of the strongest on record, formed in the Pacific Ocean. The new research finds easterly winds in the tropical Pacific Ocean stalled a potential El Niño in 2014 and left a swath of warm water in the central Pacific. The presence of that warm water stacked the deck for a monster El Niño to occur in 2015, according to the study’s authors.

El Niño and La Niña are the warm and cool phases of a recurring climate pattern across the tropical Pacific Ocean called the El Niño-Southern Oscillation, or ENSO. The warm and cool phases shift back and forth every two to seven years, and each phase triggers predictable disruptions in temperature, wind, and rain across the globe. During El Niño events, water temperatures at the sea surface are higher than normal. Low-level surface winds, which normally blow east to west along the equator, or easterly winds, start blowing the other direction, west to east, or westerly.

In the spring of 2014, strong westerly winds near the equator in the western and central Pacific Ocean created a buzz among scientists – they saw the winds as a sign of a large El Niño event to come in the winter of 2014, said Aaron Levine, a climate scientist at the NOAA Pacific Marine Environmental Laboratory in Seattle, Washington, and lead author of the new study accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.

But as the summer progressed, El Niño didn’t form the way scientists expected it to: sea surface temperatures in the eastern Pacific never warmed enough to truly be called an El Niño, and the buzz fizzled out.

But then, in the spring of 2015, episodes of very strong westerly wind bursts occurred and became more frequent throughout the summer. Following a pattern set by previous large El Niños, 2015 to 2016 became one of the three strongest El Niños on record, along with 1982 to 1983 and 1997 to 1998, Levine said.

Levine and others wondered whether the stalled El Niño from 2014 and the monster El Niño of 2015 were somehow related, he said.

In the new study, Levine and co-author Michael McPhaden, fellow climate scientist at the NOAA Pacific Marine Environmental Laboratory, examined changes in sea surface and sub-surface temperatures, winds, and volumes of warm water in the Pacific Ocean from 2014 to 2016. They also used a mathematical model to analyze how these factors were related.

“As an El Niño develops and matures into its peak phase, [warm water] gets discharged out of the equatorial regions to the polar regions,” Levine said. In 2014, easterly winds prevented that warm water from being transported poleward. The warm water stuck around through the winter and was available as a reservoir of heat that could be tapped into the following year. “Once we started to get some additional westerly winds – unusually strong westerly winds that occurred in the spring and summer of 2015 – an El Niño developed,” he said.

Looking further back into the climate record, Levine and McPhaden found a similar event occurred in 1990. That year, easterly winds counteracted a budding El Niño, and leftover warm water fueled El Niño conditions in 1991 to 1992.

“It’s nice to see that even in the 35-year record we have something similar that gives us confidence that this was the physical mechanism that was going on,” Levine said.

Predicting future El Niños

While Levine’s research shows what conditions can help to explain past El Niños, predicting future El Niños is much more difficult. For example, warm sea surface temperatures make it more likely for an El Niño to occur, but cannot be used to predict El Niños with absolute certainty, Levine said.

Sea surface temperatures and winds are closely coupled – meaning that they strongly influence each other, said Michelle L’Heureux, a climate scientist at NOAA’s Center for Weather and Climate Prediction in College Park, Maryland, who was not involved in the new study. According to L’Heureux, certain winds are predictable to a certain degree, but there are still elements of surprise.

“The wildcard in all of this – the reason this is very probabilistic and we can’t say anything with certainty – is that some part of the winds are essentially random,” L’Heureux said. “We can predict them five to seven days out, but that’s not going to give you much advance information on the growth of ENSO.”

These random wind elements are a major limitation to predicting El Niño events, she said. “There’s a chance that the winds could turn off in the summertime, and that’s what happened in 2014.”

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58 thoughts on “The cause of a record warm El Niño year? Leftovers

  1. Yet again, the science isn’t settled after all.
    Can’t someone get that into the thick heads of Gore, Hansen et al.

    • Who was it who said that you can’t convince somebody of something, when their livelihood depends on their not understanding it?

      • Upton Sinclair, but quoted by Al Gore in reference to the misinformation industry surrounding climate change, centred around the George C Marshall Institute that also produced public uncertainty in the science for the tobacco industry.

      • Perhaps Mr Gore should remove the mote in his own eye before attempting to remove the speck from a brother’s eye. Who was I loosely quoting there Seth?

    • Oldseadog wrote:Yet again, the science isn’t settled after all.

      I think that the claim that the science is settled over is the fact that the current warming is anthropogenic. Not that the mechanism of the ENSO is completely understood.

      Oldseadog wrote:Can’t someone get that into the thick heads of Gore, Hansen et al.

      I don’t think they made any claims that the mechanism of the El Nino requires no further research.

      • If you cannot account for the mechanism of ENSO which drives large scale changes in Earth’s observed temperatures and weather patterns then it ought to be pretty obvious that neither can you account for any particular episode of warming. That is the whole point. If you don’t know what the natural variation mechanisms are, how they operate in detail and what the magnitude of their respective effects are then it is clearly impossible to make any reliable statement whatsoever about anthropogenic mechanisms.

      • Seth, I would be most obliged if you could give me a link to your assertation that the current warming is anthropogenic and another to identify what warming you refer to.

        For clarity I was not suggesting that they make claims about research into El Nino, just that they keep saying that the science is settled regarding climate change when it is manifest that the science is not settled about almost every aspect of climate research.

      • “Oldseadog wrote:Yet again, the science isn’t settled after all.”
        Seth is correct. Nobody claims that the science behind El Nino is settled.

        Cephus0 wrote “If you don’t know what the natural variation mechanisms are, how they operate in detail and what the magnitude of their respective effects are then it is clearly impossible to make any reliable statement whatsoever about anthropogenic mechanisms.”

        This is wrong. It is quite possible to understand the overall direction without understanding how short term fluctuations operate in detail. We understand the reason behind seasonal changes in temperature, but we do not understand what all the natural variation mechanisms are in detail. Therefore we can predict it will be warmer next July than next December, yet we cannot predict there whether there will be a cold spell in March.

        Putting aside for a moment whether we actually do understand AGW, it is clearly not impossible for us to do so whilst not understanding all the details of El Nino.

      • Seaice1 wrote: “This is wrong. It is quite possible to understand the overall direction without understanding how short term fluctuations operate in detail.”. Nice logic there. So I guess the models show us the definitive long term trend? Or is it the ocean cycles? Or is it the GISS temperature record after adjustments to selected stations. This is nonsensical. The point is that the globe’s climate is vastly more complex than even an El Nino event, and we can’t even predict that. Not being able to predict less complex events doesn’t make your predictions of even more complex long term events valid, especially when the long term event uses the same variables as the shorter, non predictable event. That makes no sense whatsoever !!!

      • Seaice, if you don’t know what the drivers of natural variation are, then it is impossible to prove that the extremely mild warming of the last 150 years is anything other than natural.
        That you wish to believe that CO2 is the main cause of it, is little more than your delusion.

      • Chilemike. “Nice logic there. ” Thank you. I wasn’t sure it would be understood.

        “This is nonsensical. The point is that the globe’s climate is vastly more complex than even an El Nino event, and we can’t even predict that.”
        My post is about the logic of what we can and cannot know. We cannot predict next month’s weather yet we know that it will be warmer in the NH than this month. We can know the broad picture without knowing the details.

        We do not predict next month will be warmer than this by adding up all the tiny weather effects. We simply observe that the orbit of the Earth means that there will be much more sunlight.

        Next month’s weather is vastly more complex than a thunder storm, yet we can’t even predict that. You are saying something akin to that because we cannot predict when and where thunderstorms will occur, we cannot predict that summer will be warmer than winter, and hence bring more thunder storms.

        MarkW. “Seaice, if you don’t know what the drivers of natural variation are, then it is impossible to prove that the extremely mild warming of the last 150 years is anything other than natural.”

        Absolute proof is not possible, but we can do it (in principle) beyond reasonable doubt. We can reject the null hypothesis using only statistical means. Of course that is not proof. That is why I prefer physical reasoning to explain the events we observe. If we were totally ignorant of the drivers then we could say very little, but we are not totally ignorant.

      • Seaice1

        You are in essence claiming that long term climate warming resulting from a CO2 concentration increase is ‘knowable’ in advance because ‘it is understood’ without having to understand that there will or will not be storms of a certain magnitude resulting from it.

        I do not see how anyone can reasonably predict long term warming from an increase in CO2 concentration because the evidence is that such predictions, based on the science and mathematics built into the models so far, show no skill at all. Not including the tropical thunderstorm hypothesis into the models is a huge gap as the effect far exceeds any warming that might come from any viable claim for an increase in CO2 emissions. Denial of this lack of modelling skill is unbecoming. Gavin, particularly, has been selling the idea for years that ‘climate is knowable and predictable far in advance even if weather is not’. BS.

        Your example of the weather in the NH being warmer this summer than it is now is not a ‘prediction’, It is a forecast based on the past, not an understanding of how the climate system works. In fact the increase is not the result of climate functions at all. It is no more valid than claiming that your model for planetary rotation ‘predicts with skill’ that the sun will rise tomorrow in the East. There is no skill involved in that prediction. Two year old can do it based on experience.

        Predicting that the global temperature will rise to 8.5 degrees above its current value if emissions of CO2 continue at the present rate is forecast that requires skill. There are GCM’s (models) that forecast such a temperature rise. I believe they have no skill. Why? Comparing the temperature rise since 1996 and now, while comparing the predictions of a model that attains 8.5 deg rise by 2100, and also observing the magnitude of the increase in the concentration of CO2 since 1996 leads me to the conclusion that the modellers do not understand well enough how the climate works to be able to make an accurate prediction for the year 2100.

        My observation is they have not been able to make an accurate temperature prediction for 2005, or 2010, or 2015. I am sure they will fail again in 2020. Their understanding if the climate it not up to the task of predicting the temperature, based on the CO2 concentration, for even 1 year let alone 100.

      • Crispin “You are in essence claiming that long term climate warming resulting from a CO2 concentration increase is ‘knowable’ in advance because ‘it is understood’ without having to understand that there will or will not be storms of a certain magnitude resulting from it.”

        No, that is not quite correct. I am saying that the fact we do not know the detail of events like El Nino does not mean that the long term trend is unknowable. I have not even mentioned CO2. I said specifically “putting aside whether or not we actually understand AGW”. These distinctions are important.

        The argument presented by Cephus0 and others is that becasue we cannot predict an El Nino, we cannot predict a long term trend. This argument is wrong, as I have explained.

        Whether or not we actually do understand the long term trend is another question, but the inability to predict El Nino does not mean it is unknowable.

        After all, that would mean an inability to predict every bounce of a rock rolling down a hill would mean that we couldn’t predict the downhill trend. We do not analyse the trend by adding up every detailed movement.

      • “After all, that would mean an inability to predict every bounce of a rock rolling down a hill would mean that we couldn’t predict the downhill trend. We do not analyse the trend by adding up every detailed movement.”

        Your analogy doesn’t work. We know things go downhill because we understand exactly why – gravity. We don’t know that the Earth is warming in an “unnatural” way, that’s what we are trying to work out. If we don’t know what is natural, we can’t know what is not natural. Agai, this is the crux of the argument – what s natural?

        You can’t claim to know the warming is unnatural even though we don’t know what is natural just because you see a trend.

  2. is that some part of the winds are essentially random,” L’Heureux said. “We can predict them five to seven days out,
    ===
    certain winds are predictable to a certain degree
    ===

    But you wouldn’t know that until it actually happens….so you can’t predict winds at all

    • But… If I predict winds and I’m right, then I can predict winds. Sometimes my predictions are wrong. See?

      • if some winds are random and you dont know which ones, your “predictions” are just a bet, nothing more.
        If there is a random element then any accuracy is just luck, if you guess 4 when you throw a dice, and 4 comes out, you think your “prediction” useful? :D

  3. Nothing new here. This is what Joe Bastardi has been showing at Weaterhbell for the last 2 years.

    • The overall temperature of the ocean and its spatial pattern is what sets up the pressure differentials so that the Trade Winds become either weaker or stronger than normal. So the temperature of the water itself becomes its own self-reinforcing mechanism.

      The initial driver is the general temperature of the ocean itself and whether cold or warm water is surfacing at the Galapagos Islands from underneath in the Undercurrent.

      Last year, it was warm water surfacing from the Undercurrent which lead to an El Nino – now it is cold water surfacing which will lead to La Nina. And there is only 12,000 kms long, times 700 kms wide time 0.1 kms deep worth of ocean we are talking about here or 840,000 km3; 100 times as much as Lake Superior so no small amount.

    • And here is some proof of that.

      First, the Equatorial Upper Ocean Temperature Anomaly (180W to 100W; which is mainly the ocean temp at 100metres to 300metres, not the surface, ie the water temp in the Pacific Equatorial Undercurrent) versus the Pacific Trade Wind Index.

      Source data:

      http://www.cpc.ncep.noaa.gov/data/indices/

      http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt

      And this same Equatorial Upper Ocean Temperature Anomaly versus the Nino 3.4 Index itself. In both cases, the Equatorial Upper Ocean Temperature Anomaly (the anomaly of the water in the Undercurrent) is leading the Trade Winds and the ENSO index which matters the most by 1 – 2 months (almost ALL the time).

      Source Data:

      http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt

      http://www.cpc.ncep.noaa.gov/data/indices/sstoi.indices

      • Thank you Bill Illis

        “In both cases, the Equatorial Upper Ocean Temperature Anomaly (the anomaly of the water in the Undercurrent) is leading the Trade Winds and the ENSO index which matters the most by 1 – 2 months (almost ALL the time).”

        I have long held a suspicion that the model implying El Nino is driven by wind direction is too simplistic. I am also pleased to see that the mechanism of cooling by water being shifted to higher latitudes is being integrated. We can become too easily preoccupied with the equatorial region and migration running W-E. It is N-S that matters as this influences rates of cooling. The rafting of warm water eastwards is probably only a symptom of some other driving force

      • All that correlation shows is they correlate, it does not show a driver, something else can be driving both.

  4. I’ve windsurfed for almost 30 years. I can assure you that wind is a ficle beast. Pressure gradients can’t be predicted very far in advance and can change rapidly.

  5. Indigestion?

    The scientific philosophy is established on the logical premise that accuracy is inversely proportional to the product of time and space offsets from an established reference.

    The system can only be characterized as probabilistic in a limited frame of reference. It is chaotic outside of this “scientific domain” because the system is incompletely, and, in fact, insufficiently characterized, and unwieldy. Even with modern computing resources, simulations constrained to a limited frame of reference overlook a confluence of known minor processes, and poorly represents first-order processes.

  6. They’ll still hold “Climate Change” as the fall back position but if it is a warmer summer then we’ll start to hear the minions use “Global Warming” again.
    No need to provide evidence of a cause. They need only imply.
    I believe there’s a logical fallacy, “After the fact, therefore because of the fact.”
    Perhaps a political science fallacy twist should be added?
    “We’ve altered (chosen?) the facts, therefore we must act!”
    (Or words to that effect. 8-.)

    • Sick of reading this myth. The first person to actually promote this exact change of terminology was AGW skeptic, Republican party strategist Frank Luntz. And why do you think he was promoting it?
      Political spin at the behest of big business. http://www.motherjones.com/files/LuntzResearch_environment.pdf -see the conclusion.

      In recent times it has conveniently morphed into ‘they’ (leftist, liberal alarmists) are trying to trick us by changing stuff.
      The irony is breathtaking.

      • You don’t understand irony. All you are doing is assuming that if a Republican did a bad thing once, then all Republicans are bad.

        That’s not irony, it’s childish bigotry.

        If I tell you that a black man once committed a crime, does that mean they are all criminals?

  7. Yes and No.

    “The wildcard in all of this – the reason this is very probabilistic and we can’t say anything with certainty – is that some part of the winds are essentially random,” L’Heureux said. “We can predict them five to seven days out, but that’s not going to give you much advance information on the growth of ENSO.”
    ________________________

    Ongoing Probability. Yes.

    No Randomness at all -we know 4 years El Niño, one La Niña – from observations.

    What’s missing: quantification of observed mechanisms. Stuck on.

    Whenever it’s anthropology scientists regress to Cult.

    Whenever its physics scientists regress to Randomness.

  8. “The cause of a record el Nino year? Adjustments.

    The 2016 el Nino was an unexceptional Modoki which failed to engage the Bjerknes feedback. The only reason for claims of “record” is the adjustment of SST baselines for the Pacific in 2014. This lifted Pacific and global temperatures, as ordered for the Paris conference and Obama’s legacy posturing.

  9. If the air above the ocean is cooler than normal, won’t the oceans release more heat than normal? Hence – 18 years of cooling and larger than average El Nino’s?

    • PS – my point is that it is the difference in temperature that powers El Nino’s. That seems logical to me. One might say that the size of this present El Nino was caused by the 18 year pause.

      • That sounds plausible on the face of it, but where does the heat come from in the first place? Simplified, we have atmosphere and ocean, energy in from sun and energy radiated out to space.

        If we have a system that has no net energy input, it is in equilibrium. If the ocean stores energy it must get it from somewhere. Since there is no net energy input, it must get it from the atmosphere. We would expect a drop in atmospheric temperatures as energy moved into the ocean, followed by a sudden rise as El Nino returned the energy to the atmosphere. This would return the temperature back to the original.

        If the atmosphere does not cool down, as observed during the pause, yet the ocean is storing extra energy, then that energy must come from somewhere. It is likely that the system is not in equilibrium, and there is a net energy input. This goes into the ocean rather than the atmosphere. We see a steady atmpospheric temperature, but then the stored energy is returned in a big El Nino and we see a big jump. This puts the temperature higher than before the last El Nino.

      • @ seaice1, can you give a historical or paleoclimatological example of the system you describe being in equilibrium?

      • Equilibrium is a tricky subject. A lot depends on the time frame you are talking about.
        The earth routinely stores energy only to release it, sometimes weeks to months later other times years to decades later.

      • An example is the Moon. This is close to equilibrium, but not completely so.

        The Earth will never be perfectly at equilibrium, as MarkW says. There will always be some net imput or output, because energy is stored and moved about. That does not change the argument. Sloshing energy about will even out over time, sometimes gaining and sometomes losing energy. I do not think there is a sensible mechanism that matches the observations other than a net input of energy over recent decades.

        El Nino can only move energy around. Whatever mechanism you use to try to explain the observations must include this fact. EL Nino is not a source of energy, so cannot be responsible for warming of the system. It can be a source of warming of part of the system – i.e. the atmosphere, but only with equal loss of energy of another part – i.e. the oceans.

        If a series of Los Ninos were to be the source of the atmospheric warming, then the heat content of the oceans would have to be reducing. This does not match observations.

      • seaice1 says:

        The Earth will never be perfectly at equilibrium… There will always be some net imput or output, because energy is stored and moved about… Sloshing energy about will even out over time, sometimes gaining and sometomes losing energy.

        That sounds just like what scientific skeptic Prof Richard Lindzen says:

        The notion of a static, unchanging climate is foreign to the history of the earth or any other planet with a fluid envelope. The fact that the developed world went into hysterics over changes in global mean temperature anomaly of a few tenths of a degree will astound future generations… Climate is always changing. We have had ice ages, and warmer periods when alligators were found in Spitzbergen. Ice ages have occurred in hundred-thousand year cycles for the last 700 thousand years, and there have been previous periods that appear to have been warmer than the present, despite CO2 levels being lower than they are now. More recently, we have had the Medieval Warm Period, and the Little Ice Age. During the latter, alpine glaciers advanced, to the chagrin of overrun villages. Since the beginning of the 19th Century these glaciers have been retreating. Frankly, we don’t fully understand either the advance or the retreat.

        For small changes in climate associated with tenths of a degree, there is no need for any external cause. The earth is never exactly in equilibrium. The motions of the massive oceans where heat is moved between deep layers and the surface provides variability on time scales from years to centuries. Recent work (Tsonis et al, 2007), suggests that natural variability is enough to account for all climate change since the 19th Century.

        seaice1 and I disagree on a lot of things, but he can’t possibly be wrong about everything. ☺

        What’s being observed is entirely natural. There is no credible evidence that human CO2 emissions are the cause of any changes in global temperature, or Arctic ice, or anything else. Maybe seaice1 is finally beginning to see the light. Stanger things have happened. Not many. But it’s not impossible that the scales are falling from seaice1’s eyes.

      • Seems to me that the amount of sea surface insolation that makes it past the daily cloud formation in the lower and middle latitudes should be the variable that you are searching for as a net heat gain or loss regulator in the Pacific.

  10. Can someone tell me how a sea surface anomaly can be measured within an 8 centimeter range when there are 10 meter waves happening? How do they arrive at this?

    • Law of large numbers. The more measurements, the greater reduction to the mean. Satelites provide millions of measurements daily as they track swathes of the ocean surface. For a particular location at a given time the resolution is poor, but over a larger area/longer time the accuracy becomes better. Trends over time have even better accuracy – the longer the period, the narrower the uncertainty for the trend.

      Tide gauges are less accurate than satellites. They are measured a few times a day, so each day has some averaged result. Still, over time, these larger variances resolve to a more accurate mean.

      None of it is precise, of course, but more measurements do indeed resolve to better accuracy. The remaining uncertainty is usually expressed as +/- ‘x’: as in, trend 3.3 mm/yr (+/- 0.4mm). That’s the uncertainty for the satellite trend.

      Think of flipping a coin. If the coin is balanced you know beforehand there’s a 50/50 chance of it landing heads. But you could easily measure a 8/2 ratio over 10 flips. When you get to 10,000 flips, the ratio will be much closer to 50/50. Law of large numbers.

  11. We can talk in terms of basic equilibrium which accommodates short-term fluctuations and slower long term low-rate change. Most of Earth’s systems act in this manner. It is clearly displayed in the rock record: cycles within cycles within cycles of different time frames

    El Nino can be the result of short-duration pulses in energy input

    or/and

    Changes in rates of cooling

    I suspect the latter: During the build-up of an El Nino warm water that is usually transported to cooler latitudes gets trapped in the equatorial region due to the break down of the relevant water and air currents. If this hypothesis is correct we should see some cold anomalies in the higher latitudes during an El Nino

    The key question is: what triggers this? A trigger does not have to be significant in such a dynamic system. It could also just be a ‘tipping of a scale” – a steady build up that over-balances. The regularity of ENSO suggests this may be the case

  12. “As an El Niño develops and matures into its peak phase, warm water gets discharged out of the equatorial regions to the polar regions,” Levine said. In 2014, easterly winds prevented that warm water from being transported poleward. The warm water stuck around through the winter and was available as a reservoir of heat that could be tapped into the following year. “Once we started to get some additional westerly winds – unusually strong westerly winds that occurred in the spring and summer of 2015 – an El Niño developed,” he said.

    If this is true, we should see an increase in Arctic sea ice in the year preceding a strong El Nino due to less warm water being transported from equatorial to polar region. See chart below

    The biggest increases in Arctic sea ice occurred in 1996 and 2014, the years preceding the strongest El Nino’s in 1997-98 and 2015-16. It appears the ‘leftover theory’ is plausible. Perhaps sea ice could be a leading indicator of strong El Nino’s.

  13. It’d be nice if they could go back further. When we first had our out of season el Nino which fizzled, people were going on about “record hot year, and there isn’t even an el Nino”. We ended up with the warm blob, and records high temps in data sets that combined SST and surface atmosphere temps. A commenter at Judith Curry’s (capt dallas) pointed out that we had similar SSTs in northern pacific in the late 50s/early 60s, around the time of a hiatus in surface temp rise and just before a large increase in arctic sea ice, and the record 2013/14? temps were only few hundredths of a degree warmer.

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