More data fiddling – this time in NOAA's ENSO data

Plot below showing ONI -vs- Aqua Channel 5 Temperature from lukewarmplanet (not Tisdale) to illustrate what he is talking about in his upcoming book. – Anthony

Anomaly plot along with the “ONI” (Oceanic Nino Index). In this plot ONI leads the channel 5 data by three months.

Comments on NOAA’s Recent Changes to the Oceanic NINO Index (ONI)

Guest post by Bob Tisdale

As many of you are aware, I’m writing another book. The working title is The Ignored Driver of Global Climate: El Niño- Southern Oscillation. I’m about two-thirds of the way done, I believe. There’s lots of new illustrations (so far about 70% are new), and they should help those who are having trouble understanding the processes of El Niño-Southern Oscillation (ENSO).

I’ve just finished a discussion of NOAA’s recent changes to their Oceanic NINO Index, also known as ONI, in the chapter about ENSO Indices. I believe you’ll find it interesting. (I’ve left the illustration numbers as they presently exist in the book draft.)

NOAA’s Climate Prediction Center (CPC) recently modified their Oceanic NINO Index (ONI). Refer to their Description of Changes to Oceanic NINO Index webpage for a complete write-up. There they note in the opening paragraph:

Due to a significant warming trend in the Niño-3.4 region since 1950, El Niño and La Niña episodes that are defined by a single fixed 30-year base period (e.g. 1971-2000) are increasingly incorporating longer-term trends that do not reflect interannual ENSO variability. In order to remove this warming trend, CPC is adopting a new strategy to update the base period.

NOAA does not attribute the “significant warming trend” to anthropogenic greenhouse gases, but anytime that phrase is used it implies manmade warming to many persons. Unfortunately, what NOAA has actually done with their changes is minimize the impact of the 1976 Pacific Climate Shift on NINO3.4 sea surface temperature anomalies.

I cannot fathom why they would do that when the 1976 Climate Shift is the subject of numerous scientific studies. Google scholar has 176 returns for “1976 climate shift”, in quotes. It is an accepted, well-documented phenomenon.

The Oceanic NINO Index is based on the NOAA ERSST.v3b sea surface temperature dataset. Yup, that’s the dataset that NOAA introduced in 2008 with bias-corrected satellite data and then quickly modified, removing the satellite-based data, when “users” at NOAA discovered that the satellite data made global sea surface temperatures in 1998 warmer than 2003 by a couple hundredths of a deg C. Refer to the discussion of Figure 2-23 in Chapter 2.

Figure 4-21 illustrates the ERSST.v3b-based NINO3.4 sea surface temperature anomalies, on which the Oceanic NINO Index data is based. The data does in fact have a positive linear trend of slightly less than 0.06 Deg C per decade. Note that I’ve highlighted 1976 to point out the Climate Shift.

So let’s look at the data before and after the climate shift.

 

The ERSST.v3b-based period average sea surface temperature anomalies for the NINO3.4 region from January 1950 to December 1975 and from January 1977 to May 2012 are shown in Figure 4-22. The average sea surface temperature anomalies after the 1976 Pacific Climate Shift are about 0.3 deg C higher than they were before it. By the way, that shift impacted the entire Eastern Pacific Ocean, not just the eastern equatorial Pacific.

And of course the linear trends before and after the climate shift are negative, Figure 4-23, and that implies the climate shift is responsible for a good portion of the overall positive linear trend from 1950 to present.

To “remove” the “significant warming trend” caused in part by the 1976 climate shift in the sea surface temperatures of the NINO3.4 region, NOAA no longer uses a single set of base years (1971-2000) for the anomalies in their Oceanic NINO index. They now use a series of shifting base years. They explain:

ONI values during 1950-1955 will be based on the 1936-1965 base period, ONI values during 1956-1960 will be based on the 1941-1970 base period, and so on and so forth.

The result: NOAA has eliminated the positive trend in what used to be sea surface temperature anomalies of the NINO3.4 region. See Figure 4-24. One can’t even call them sea surface temperature anomalies anymore with the sliding base years. But for now, we’ll treat them as anomalies.

With the changes, NOAA has minimized the difference in the period-average NINO3.4 sea surface temperature “anomalies” before and after the 1976 shift. Based on the “raw” ERSST.v3b data, the climate shift caused NINO3.4 sea surface temperature anomalies to shift up 0.3 deg C, but the “corrections” dropped the shift to about 0.04 deg C, as shown in Figure 2-25.

And the changes to the way NOAA calculates sea surface temperature “anomalies” for the Oceanic NINO Index has resulted in more severe negative trends before and after the climate shift. See Figure 4-26.

I won’t speculate about why NOAA would want to minimize the effect of the 1976 Pacific Climate Shift. The reason given for the changes seems odd at best. Consider this though: There are scientific studies where the authors remove the linear effects of ENSO on global surface temperatures by simply scaling and subtracting an ENSO index from global surface temperatures. The authors then mistakenly claim the remaining trend in global surface temperatures is the result of anthropogenic global warming. This faulty method of determining the effects of ENSO on global surface temperature is discussed further in Section 6.  Now, because NOAA has flattened the Oceanic NINO index trend, if someone were to use it in one of those misleading scientific studies, the remaining trend in global surface temperature residuals would be a little bit higher than if they had used a sea surface temperature anomaly-based ENSO index.

In summary, because the Oceanic NINO index no longer represents the sea surface temperature anomalies of the NINO3.4 region using a single base period, and because NOAA has minimized the impact of the 1976 Pacific Climate Shift in it, and because that climate shift exists in all sea surface temperature datasets, I, personally, would not use Oceanic NINO index as an ENSO index. Then again, I don’t believe NOAA cares one way or the other if I use their Oceanic NINO index.

INTERESTED IN LEARNING MORE ABOUT THE EL NIÑO-SOUTHERN OSCILLATION AND DON’T WANT TO WAIT FOR MY NEW BOOK?

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.

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It has gotten to the point that “the data” is essentially meaningless, hasn’t it? With all the fiddling and diddling (I mean, c’mon, 0.02 of a degree???) where is this taking us?

You could also add the CMIP model mean run for the ENSO 3.4 region.
http://climexp.knmi.nl/data/icmip5_tas_Amon_modmean_rcp60_190-240E_-5-5N_n_++a.png

Richard Nelson

Emitting massive amount of CO2 into the atmosphere is bad. Point, who care what is does to climate. Big Oil is going down despite its effort to disinform.

rabbit

“The Ignored Driver of Global Climate: El Niño- Southern Oscillation”
That’s a little clunky even for a working title.

rabbit says: “That’s a little clunky even for a working title.”
I’m open to suggestions.

Slightly OT – but I really think everyone should check out these two threads on the Fortean Times message board, because they seem to me to personify *everything* that’s wrong and scary about the way this issue taps into the human capacity for bigotry and closed-thinking. So many intelligent people who haven’t studied this subject have such ludicrous misconceptions, a board like that is a good outreach place to try and get some real info in place
http://www.forteantimes.com/forum/viewtopic.php?t=48718&postdays=0&postorder=asc&start=0
http://www.forteantimes.com/forum/viewtopic.php?t=951&start=1695

“Richard Nelson says:
June 5, 2012 at 12:26 pm
Emitting massive amount of CO2 into the atmosphere is bad. Point, who care what is does to climate. Big Oil is going down despite its effort to disinform.”
So Mr Nelson, have you actually anything to contribute to this thread?

Ged

@Richard Nelson,
All the photosynthesizing plants on the planet, which require CO2 for sustenance, would tend to disagree with you.

ianrs

Richard
Wake up and give your head a shake.

Owen in GA

Richard Nelson: as this is an internationally read blog, I will give you the benefit of the doubt that English is not your first language, because your three sentence missive makes absolutely no sense. If I edit it to what I think you meant, it still shows that you drink copious quantities of Mannian Kool Aid. Either that or you REALLY need to use (/sarc) tags.

Gunga Din

Richard Nelson says:
June 5, 2012 at 12:26 pm
Emitting massive amount of CO2 into the atmosphere is bad.
=========================================================
Me: Just because you say so?
========================================================
Point, who care what is does to climate.
========================================================
Me: Point, we’ve been lied to about what it does to climate.
========================================================
Big Oil is going down despite its effort to disinform.
=========================================================
Me: You mean like the funding “Big Oil” has given to “The Team”? Maybe it’s Big Government that needs to go down?

graphicconception

“I’m open to suggestions.”
El Niño: Climate Driver?

davidmhoffer

OK, I read the article twice and I am confused.
The way the explanation reads, they are publishing anomaly data but they change the base period against which the anomaly is calculated every few years. Please, someone tell me that I read that wrong. Please.

Gunga Din

Bob Tisdale says:
June 5, 2012 at 12:56 pm
rabbit says: “That’s a little clunky even for a working title.”
I’m open to suggestions.
=======================================================
“El Nino: The Backseat Driver”?

Ian W

It is becoming more and more apparent that the agencies who have been tasked with maintaining data about the climate are not up to the task. There is apparently no quality control, no data management, no configuration management, no traceability of changes made. E. M. Smith – Chiefio has been doing a forensic examination of the changes between GHCN V1 and GHCN V3 ( http://chiefio.wordpress.com/2012/06/01/ghcn-v1-vs-v3-1990-to-date-anomalies/ and following posts) ) This examination shows the same (to be charitable) lack of quality control.
According to the AGW protagonists, we are hazarding the very future of the human race and therefore having to spend untold trillions allowing other minor emergencies like children dying of starvation every 5 seconds to be disregarded – as the changes in the world’s climate are of overwhelming importance! Yet maintenance of the data on the climate appears to have been left to bungling amateurs who would be summarily dismissed in any field except apparently climate science. I have seen better quality control and data management in undergraduate projects.
I know the rule is to “Never ascribe to malice that which can be explained by incompetence.” But such repeated and widespread ineptness stretches the bounds of credibility.

davidmhoffer

This is your Global Warming
This is your Global Warming on Drugs
Where is the FCC?

kadaka (KD Knoebel)

From Bob Tisdale on June 5, 2012 at 12:56 pm:

I’m open to suggestions.

ENSO: Global Climate Driver
How the El Niño- Southern Oscillation controls the climate and your weather

Although to properly establish the relationship, as ENSO works with whatever heat is provided by the Sun, and only what’s allowed through by the clouds, it’s as much of a “driver” as a GPS unit.
ENSO: Navigator of the Global Climate
How the El Niño- Southern Oscillation directs the climate and your weather

Bill Illis

8
We need to take this function away from the NOAA and the NCDC.
Basically, the Nino 3.4 region has no trend over the longest time-scales (even reconstructions going back hundreds of years). This is extremely important because it is one of the few places on the planet that has not increased over time and it tells you something important about what this phenonmenon is – the Pacific’s thermostat.
I’ve speculated before that the reason it does not have an increase is because the adjusters have not felt they could get away with adjusting it up (until now).
There are a long series of actual ship measurements going far back in time. There is the tie-in to the Southern Oscillation Index which is carefully measured atmospheric pressure. 1877-88 was clearly a Super El Nino with well-recognized impacts around the globe. You can’t go back and adjust a Super El Nino into a La Nina. So, they had to leave these numbers alone.
The fact that NOAA and the NCDC have been getting away with all these continual adjustments in the last decades just means they now feel “brave enough” to try it with the ENSO as well.
Leave the temperature records alone (or some politician will have to come in and reorganize how things are done – we need to elect one of those).

I seem to recall a proposal to for a different way to define the ONI for comparing with past climates was suggested by Mike Palecki at an AMS meeting around 2008 IIRC. I have the link at home to his talk (which was actually quite good!) and will post it later. However, his reasons for creating a “moving ONI” seemed justifiable in context: one must balance the number of events occuring over time if one is to compare the relationship to extreme events in either kind of ENSO event. I myself created a sort of “invariant ENSO index” that would help isolate events that were large compared to their contemporary period. My motivation was that, in generating ENSO composites based on exceptional years, the claim might be made that exceptional year’s timing is cofounding a long term trend signal. With my IEI, the twenty largest ENSO negative events and twenty largest ENSO positive events since 1895 (for comparison with the US Climate Division maps) were very evenly distributed throughout the period. No one could accuse me of confounding ENSO signals with anything else. The downside being I lose some of the long term ENSO signal, and can’t estimate it’s role in multidecadal trends in US temps.
Of course, one should always be able to generate the old ONI using the old techniques and raw data. That it won’t be officially reported and won’t be officially used is unfortunate.
BTW Bob, I realize you are mainly focused on the large scale climatic effects of ENSO, rather than the weather and smaller scale patterns associated with (but not necessarily caused by) the individual events, but would you have any guesses as to why ENSO events of either sign (and again the ENSO events are identified using a normalized index so I’m not capturing a warming signal-even if it wasn’t normalized, look at the years!) seem to be associated with warm anomalies over overlapping parts of the US?
El Nino composite:
http://i23.photobucket.com/albums/b370/gatemaster99/IEIElNinoTemp.png
La Nina composite:
http://i23.photobucket.com/albums/b370/gatemaster99/IEILaNinaTemp.png
You can generate your own composites like these here:
http://www.esrl.noaa.gov/psd/data/usclimdivs/

Lord Beaverbrook

A suggestion for the book
Massaging the Global Heartbeat: ENSO an Irregular Pulse

D. J. Hawkins

Bob Tisdale says:
June 5, 2012 at 12:56 pm
rabbit says: “That’s a little clunky even for a working title.”
I’m open to suggestions.

Global Climate’s Hidden Hand
The El Niño-Southern Oscillation

I am skeptical of any kind of an abrupt, basin wide shift of anything. Nature usually does not work that way. My major suspicion is interment calibration. That said I am not a fan of using linear trends or anomalies for much of anything either. In the attempt to simplify these things appear to create confusion and are simply more models of which we have to many now.

We need a new scientific definition for information that has been roundly filtered, pureed, adjusted, tweaked, and spiked until it no longer reflects actual reality. Some suggested terms: spooge, junk, garbage, slime….

Richard Nelson says:
June 5, 2012 at 12:26 pm
— — —
96 % of global emissions come from nature. The Earth needs at bare minimum about 180 ppm CO2 just to keep the plants alive, with 280 ppm being the pre-industrial level. Most of the “heat trapping” effect has taken place at this level and man’s contribution has an ever diminishing affect as per the inverse exponential (logarithmic) effect of increases concentrations. Humans are not causing catastrophic climate change / global warming.

Lorax

In 1976 I happened to be navigator on a Matson ship running between the West Coast US to Hawaiian Is. and NOAA paid each watch officer to launch their probe for sea temp at various depths… Info was closely guarded….Later in 1979 we read in Scientific American magazine about a New Ice Age approaching they also called it climate change….Only thing I see in this 33 year old scenario is a bunch of pseudoscientists trying to obtain grant money because they cannot get a job teaching… All the data they have is short term….Mother Earth has been around the block a very very long time…Every phenomena has cycles…These erstwhile scientists who expect us to believe it is a new ice age in 79 suddenly expect us to believe that lately we are going to roast our asses off, and the wheat in Kansas also the corn in Nebraska will no longer be sufficient??? Thank you doctor of phylosophy , but IMO you are full of shit…

Richard Nelson: Thanks for being the off-topic troll.

Richard Nelson: There are a multitude of grammatical and typing errors in your June 5, 2012 at 12:26 pm comment. The odd thing? You’re attempting to promote your freelance science writing business with the freelancesciencewriting.com link attached to your name. I don’t think you’re going to find many takers with your poor grammar and typing skills.
Ciao

Dennis Nikols, P. Geo says: “I am skeptical of any kind of an abrupt, basin wide shift of anything.”
There are volumes of data that show ENSO events exist.

As promised, the AMS talk I mentioned, which speaks of constructing a “moving ONI” much like what NOAA is now issuing:
http://ams.confex.com/ams/13MontMet17AP/techprogram/paper_141191.htm
It made sense in context. Also, the work he used it for is actually quite fascinating. It would be nice to see what the graphs look like with the most up to date data. Based on prior talks, his quality control work was on going (and may still be) on the Forts data, and this lead to substantial revisions.

kadaka (KD Knoebel) says: “Although to properly establish the relationship, as ENSO works with whatever heat is provided by the Sun, and only what’s allowed through by the clouds, it’s as much of a ‘driver’ as a GPS unit.”
ENSO also dictates tropical Pacific cloud cover, which in turn impacts the amount of downward shortwave radiation available to recharge the Pacific Warm Pool for the next El Niño. I’ll continue to use the word driver.

Matt G

We need government(s) to stop this data fiddling before all of it is ruined forever. I can think of nothing worse than changing data just because of an assumption. Climate science should be more appropriately be renamed climate assumption.

Andrew, regarding the start of your June 5, 2012 at 2:42 pm comment, ONI is intended as a means of identifying official El Niño and La Niña events. Does it really matter to most visitors to the ONI webpage that the 2005/06 La Niña did not exist in the old ONI but does in the new version? No. But NOAA has changed the surface temperature record in order to redefine ENSO, eliminating the impacts of a massive climate event in the process.
Also, thanks for the link.
You asked, “…would you have any guesses as to why ENSO events of either sign…seem to be associated with warm anomalies over overlapping parts of the US?”
Try separating East Pacific from Central Pacific El Niño events during the satellite era.
Also, La Niña events really aren’t the opposite of El Niño events. La Niña is, in many respects, simply an exaggerated ENSO-neutral state. Would we expect their impacts on regional temperatures to oppose one another?

Gail Combs

Richard Nelson says:
June 5, 2012 at 12:26 pm
Emitting massive amount of CO2 into the atmosphere is bad. Point, who care what is does to climate. Big Oil is going down despite its effort to disinform.
____________________________________
HUH???
Thanks to the increase in CO2 we have nearly doubled the production of food from one acre from 1/5 of a bushel of wheat to 1/3 of a bushel of wheat. So how the heck is that bad? As far as temperature goes, large parts of Canada and Russia and China can grow grain. If the season get too short/cold they can not.
Bye the Bye, Big oil is 100% behind CAGW and has been from the start. Maurice Strong, chair of the first Earth Summit, is BIG OIL and a senior advisor to the World Bank. Shell and BP funded CRU. Shell Oil exec Ged Davis is a big wig at IPCC. The former head of the IPCC, Robert Watson, works for the World Bank. The finger prints of Big Oil and the Big Banks are all over the Global Warming Scam because it is a HUGE money maker.
Do a bit of research instead of believing the propaganda you read in the Huff & Puff and Grauniad.

Gail Combs

D. J. Hawkins says: @ June 5, 2012 at 2:54 pm
Global Climate’s Hidden Hand
The El Niño-Southern Oscillation
________________________________
I like that suggestion.

Gail Combs

mikelorrey says:
June 5, 2012 at 3:20 pm
We need a new scientific definition for information that has been roundly filtered, pureed, adjusted, tweaked, and spiked until it no longer reflects actual reality. Some suggested terms: spooge, junk, garbage, slime….
________________________________
I think it has already been named as in Junk Science.

TG McCoy (Douglas DC)

How about: ”ENSO-commander of the oceans-and air..”

Bob Tisdale says: It would be interesting to see what different weather patterns are associated with the “different” El Niños. Is it possible to identify them before the satellite era? Because otherwise the population of total El Niños I’d be looking at would be reduced to one fifth and the associations with weather patterns would be on much weaker footing. Also there is the difficult of determining their normalized magnitudes. I’ll look into, anyway.
Also, with regards to whether one would expect ENSO anomalies of opposite sign to be associated with weather patterns opposite in sign, well, most areas of the US they do seem to. What I’m wonder is whether you know why the particular areas of the US that do experience warm anomalies during both types of events do so, not why any areas would. And perhaps why the anomalies in those areas happen to be warm during both types. Those areas have to have below average years also, but evidently no such years are represented among ENSO events that represent large deviations from their contemporary climate. Since ENSO evidently doesn’t cause the cool years, no matter the sign of the event, even (especially?) if it is a large negative anomaly, what does?
BTW, I recall trying, but not saving the results of a composite of minimal anomaly years in my IEI, which should be the “most neutral” years. I seem to recall the weather patterns associated with such were really odd.

kadaka (KD Knoebel)

From Bob Tisdale on June 5, 2012 at 4:40 pm:

ENSO also dictates tropical Pacific cloud cover, which in turn impacts the amount of downward shortwave radiation available to recharge the Pacific Warm Pool for the next El Niño. I’ll continue to use the word driver.

By the Willis Eschenbach Thunderstorm Thermostat Hypothesis, the amount of solar radiation received in the tropics is constrained by natural processes controlling cloud cover. ENSO works with the energy that gets through in the Pacific tropics. ENSO “dictates” tropical Pacific cloud cover in that where ENSO supplies warm water the additional energy needed for cumulus and cumulonimbus (thunderstorm) cloud formation is reduced, otherwise more energy is needed.
During the day, all of the available solar radiation is not accepted, the clouds will reject part of it. In the Pacific tropics, ENSO determines when in the day the cumulus and cumulonimbus (thunderstorm) clouds form, where ENSO operates. Thus ENSO does not appear to overly affect how much energy is received, including how much is available for storage in the Pacific Warm Pool. What’s affected is primarily when the daily maximum is received, not the amount.
What ENSO does do is direct climate and weather patterns by when, where, and how it releases the stored energy. In the El Niño discharge phase it can release extra energy that is transported outside the Pacific tropics. But ENSO’s primary effects, to me, are expressed as the steering of currents of wind and water, the shifting of circulation patterns.
Thus ENSO does not represent a motive force, a driver, but a navigator.

Kudos, D. J. Hawkins. Seriously literate.
Bob, IMHO, Nino is the horse and PDO holds the reigns.

ferdberple

Gail Combs says:
June 5, 2012 at 6:06 pm
Bye the Bye, Big oil is 100% behind CAGW and has been from the start. Maurice Strong, chair of the first Earth Summit, is BIG OIL and a senior advisor to the World Bank. Shell and BP funded CRU. Shell Oil exec Ged Davis is a big wig at IPCC. The former head of the IPCC, Robert Watson, works for the World Bank.
=========
A tax on CO2 is first and foremost a tax on coal. The cheapest, most readily available fuel source on the planet. The fuel that gave us the industrial revolution and is powering India and China out of poverty.
The CO2 tax is all about removing coal from the market. Pricing it out of existence so that oil will have a global monopoly. And once they have a monopoly, they will well and truly have us by the balls.

ferdberple

Richard Nelson says:
June 5, 2012 at 12:26 pm
Emitting massive amount of CO2 into the atmosphere is bad.
=========
Reality says otherwise. We are today feeding 7 billion people, where 60 years ago we had a whole lot more trouble feeding 3 billion. In that time we have emitted massive amounts of CO2.
This is only bad if you believe that people are the problem and thus feeding 7 billion is worse than starving the extra 4 billion we could never have fed 60 years ago, when crop failures and famine were common and global cooling was the fear.

davidmhoffer says:
June 5, 2012 at 2:07 pm
OK, I read the article twice and I am confused.
The way the explanation reads, they are publishing anomaly data but they change the base period against which the anomaly is calculated every few years. Please, someone tell me that I read that wrong. Please.
#############
Its pretty simple. It’s an index not a physical measure.

ancientmariner

If we take a stock market index and then periodically adjust the base periods from which we define the baseline we can in fact make any stock, even those that are slightly declining, appear to rise (outperform the index). This may well be the motive as suggested by Mr Tisdale.

steven mosher says: “Its pretty simple. It’s an index not a physical measure.”
Is an index useful, though, and if so, for what purposes, and what purposes not? Surely if ENSO has a physical relationship to weather patterns, it makes most sense to use a physical measure. So is shifting to an index an indication that they believe that the ENSO-weather associations are just that, associations, not physicals processes?
In some sense I welcome an admission that “teleconnections” are largely just associations of one kind of pattern with another one and don’t reflect physics in and of themselves. But is ENSO just a predictive tool when it comes to weather outside the ENSO region, or are some physical links actually valid? In my mind it makes sense that ENSO would legitimately be physically linked to some things that it is statistically associated with.

gopal panicker

yeah Mr Tisdale…i am with you…ENSO…which is a variation in an ocean current does seem to have far reaching effects…from the Asian monsoon to the Atlantic hurricane season…i would like to know why ENSO happens

gymnosperm says: “Bob, IMHO, Nino is the horse and PDO holds the reigns.”
Thanks. I’ve been wondering whether I needed to include a chapter about the PDO (It’s an aftereffect of ENSO and sea level pressure) in my book and you’ve confirmed that I do.
[When Queen Elizabeth dismounts from her horse, does she still hold the reigns in England? 8<) Robt]

Espen

steven mosher says:
Its pretty simple. It’s an index not a physical measure.
Now it is.

Andrew says: “Is it possible to identify them before the satellite era?”
I extended the El Nino Modoki Index from Ashok et al (2007) back to 1870 (the start of the HADISST dataset) and compared the results to NINO3.4 SST anomalies here:
http://bobtisdale.wordpress.com/2009/07/08/comparison-of-el-nino-modoki-index-and-nino3-4-sst-anomalies/
Andrew says: “What I’m wonder is whether you know why the particular areas of the US that do experience warm anomalies during both types of events do so, not why any areas would.”
I haven’t analyzed it.

kadaka (KD Knoebel): Willis’s Thunderstorm Thermostat Hypothesis does not contradict the known and data-supported coupled ocean-atmosphere ENSO processes. Monthly cloud amount data, downward shortwave radiation data, precipitation data, trade wind strength data, sea surface temperature data, ocean heat content data, etc all support and confirm my understanding of ENSO. Willis’s posts were about a daily cycle that limits tropical temperatures. Now introduce the variations in trade wind strength dictated by ENSO. Trade wind strength varies the evaporation rate which control Willis’s discussion. Willis’s discussion is about how and why thunderstorms occur daily. ENSO dictates where those thunderstorms occur in the tropical Pacific.