Talk:Atlantic multidecadal oscillation

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WP:LEAD. — jdorje (talk) 03:26, 8 March 2006 (UTC)

Most of the information is cut and pasted from various NOAA articles without being referenced.

Also, recent research showing the AMO circulation has been declining since the late 1990s has not been added. Lamenting that I have no time to work on this article at the moment. Margie 21:43, 2 June 2006 (UTC)


Much is needed. It reads like a copy/paste job of the AOML (PD) site...--Nilfanion (talk) 00:44, 8 January 2007 (UTC)

Wind Shear[edit]

No discussion regarding the importance of wind shear in regards to hurricane formation. —Preceding unsigned comment added by Bjunkit (talkcontribs) 04:03, 12 July 2008 (UTC)

Kerry Emanuel's postition[edit]

This article made numerous (almost POV) references to Kerry Emanuel's 2005 research into global warming and hurricane intensity. He has recently retracted these positions and now wonders if surface temperatures even matter as much as we thought for hurricanes, and he says he no longer sees much of a link at all between global warming and hurricanes.

Here is the citation from his personal article that we should probably work into this article to replace the obsolete text I removed.

<ref>{{cite web | url= |title=Hurricane expert reconsiders global warming's impact |author=Eric Berger |publisher=Houston | date=2008-04-12 |accessdate=2008-04-21}}</ref>.

Gigs (talk) 20:09, 4 August 2008 (UTC)

We shouldn't be using newspaper articles in preference to scientific papers. You seem to be over-interpreting it, and I'm not sure your removal was good. That said, we shouldn't rely on one researcher too much William M. Connolley (talk) 07:33, 5 August 2008 (UTC)
I agree I might have taken it too far, but Emanuel's 2005 work spurred a massive debate, which lead to him and others developing new models that no longer predict the same things at all. This is a rapidly evolving field, and one of the things that his 2005 work exposed was the unreliability of historical data prior to 1970. Here's Emanuel's bibliography, lots of good information here: Gigs (talk) 04:38, 5 March 2009 (UTC)

Weak or strong hurricanes influenced by AMO?[edit]

The article says:

The frequency of weak-category storms—tropical storms and weak hurricanes—is not strongly correlated with the AMO. However, during warm phases of the AMO, the numbers of tropical storms that mature into major hurricanes is significantly greater than during cool phases, at least twice as many.

What is the source for this claim added by User:Denfield almost 4 years ago? I'm asking because Chylek & Lesins (2008) basically claim the opposite:

Comparing the last 28 years (1980–2007) with the preceding 28 years (1953–1980), we find a modest increase in the number of minor hurricanes (category 1 and 2); however, we find no increase in the number of major hurricanes (category 3–5).

Could somebody help to clarify this? --bender235 (talk) 13:49, 2 September 2009 (UTC)

After no reply for three months, I'm going to change that statement now. --bender235 (talk) 10:30, 10 December 2009 (UTC)

Chylek & Lesins (2008) were investigating an increase in hurricane activity connected to a greenhouse gas induced global warming and controlled for quasi-periodic behavior (they used the AMM instead of AMO). This is the reason they used periods that overlap warm and cool phases of the AMO to examine changes in the number of minor and major hurricanes. I'm removing the statements referencing Chylek & Lesins (2008) observations on greenhouse gas induced global warming and replacing with their observation of quasi-periodic behavior. — Preceding unsigned comment added by (talk) 11:24, 5 June 2011 (UTC)

The AMO and its periodicity[edit]

Can we add a sentence like this: "Assuming that the AMO continues with its 70-year quasi-cycle, the peak of the current warm phase would be expected in c. 2020 (after peaks in c. 1880 and c. 1950)." This is basically Curry (2008), p. 35, and it's an "if-a-then-b" scheme as User:William M. Connolley requested. --bender235 (talk) 11:46, 11 October 2009 (UTC)

The trouble is, you are reduced to very little more than:"*if* something with a 70-year period continues to have a 70 year period *then* its next peak will be 70 years after its last peak". This is then completely vapid William M. Connolley (talk) 16:55, 11 October 2009 (UTC)
I agree, and specific uncertain predictions, which one might induce themselves from the graph, might better be left out. I will remove the last alinea in a few days or so, if nobody disagrees (with good arguments). --Hulten (talk) 12:38, 10 May 2010 (UTC)

(At least) two errors in [1][edit]

Bender235's edit [2] disagreed with his cited source (Enfield, Cid-Serrano) in at least the following two points (elaborated from the edit summary after request on ANI):

  • It adds "natural" to the description of AMO when E/CS explicitly come to "the conclusion that the AMO is probably comprised of both natural and anthropogenic forcing" (my emphasis) and in fact much of their paper is about that very topic.
  • It removes "approximately" from the 70 year period when E/CS explicitly list "roughly 50-90 years" - "approximately" seems even somewhat generous.

--Stephan Schulz (talk) 12:15, 11 October 2009 (UTC)

Okay, so how about: "Assuming that the AMO continues with its quasi-cycle of roughly 70 years, the peak of the current warm phase would be expected in c. 2020 (after peaks in c. 1880 and c. 1950)." --bender235 (talk) 12:39, 11 October 2009 (UTC)
  • In order to sort this out you need to use secondary sources. Wikipedia frowns on using primary sources, see WP:PSTS. Frequently articles on scientific topics contain references to primary sources, but if there is any controversy, the primary source causing the controversy should be removed, along with any text it was attempting to support. Abductive (reasoning) 13:19, 11 October 2009 (UTC)
Could you please tell us what source you are referring to? --bender235 (talk) 13:38, 11 October 2009 (UTC)
I was referring to any source that is giving you trouble. Primary scientific articles are not appropriate sources for Wikipedia if there is any controversy at all. I have no idea which of you two is correct at present, but I see what looks like attempts to analyze or extrapolate from primary sources. What you need to do is halt consideration of all primary sources from the paragraph under discussion. Ask yourself what you can say on the topic using review articles and perhaps books. Then say that and nothing more. Abductive (reasoning) 13:47, 11 October 2009 (UTC)
Well, I think Curry (2008) actually is a secondary source, isn't it? Also, I don't think User:William M. Connolley wasn't questioning the validity of my sources, but only claimed that I misinterpreted them. So instead of
The AMO assumedly runs through an 70-year cycle, and its current warm phase (after peaks in ≈1880 and ≈1950) is projected to peak in 2020.
I am now suggesting to phrase the sentence in question like this:
Assuming that the AMO continues with its quasi-cycle of roughly 70 years, the peak of the current warm phase would be expected in c. 2020 (after peaks in c. 1880 and c. 1950).
which would make it pretty similar to what Curry (2008), p. 35, says. --bender235 (talk) 14:57, 11 October 2009 (UTC)
Alright, so a book suggests that in 2020, this oscillation might be at its warmest. Why is it important that this be on Wikipedia? And for William M. Connolley, why is it important that this not be on Wikipedia? Abductive (reasoning) 20:29, 11 October 2009 (UTC)
See above; this has now reduced to "1950+70=2020" which is true but useless William M. Connolley (talk) 20:38, 11 October 2009 (UTC)
Why is it useless? Because people can add, or because it may not be accurate, or because it won't have any effect on climate? Abductive (reasoning) 20:41, 11 October 2009 (UTC)
Because people can add. In the original that B added it was "useful" but wrong, because it was called a prediction or somesuch. In the reduced version it is simply useless William M. Connolley (talk) 20:59, 11 October 2009 (UTC)
I'm unclear. What harm would be caused by the article adding, and Bender235, what harm would be caused by the article not adding? Abductive (reasoning) 23:04, 11 October 2009 (UTC)
I believe it is useful information, telling the reader that the AMO not only has an assumed 70-year periodicity, but also that its most recent peaks were in c. 1880 and c. 1950, and thus likely the next peak will be around 2020. That is valid information backed by multiple sources, and overall useful to the reader. --bender235 (talk) 23:27, 11 October 2009 (UTC)
I found this off AN/I. I'm with Bender - the information proposed is a scientifically demonstrated phenomenon, reported on in WP:RS, with a predictable cycle of occurrences. Explaining this and stating when the next one is predicted to occur seems reasonable information to include, and relying on the reader to instead scan over multiple paragraphs, as it seems WMC would prefer they do by not centralizing, or worse, not including at all, the information of the period of the cycle is ridiculous. WMC is right that both causes ought to be attributed, but that's irrelevant to the major focus of this discussion, inclusion of the period and the next peak. I support inclusion of both. ThuranX (talk) 06:10, 12 October 2009 (UTC)

(outdent) with a predictable cycle of occurrences. - no, it isn't, and even B has now admitted this William M. Connolley (talk) 07:49, 12 October 2009 (UTC)

What is your source? Or is it WP:OR again? --bender235 (talk) 11:47, 12 October 2009 (UTC)
Assuming the question is your change of mind, the source is your edit of 14:57, 11 October 2009 above William M. Connolley (talk) 12:55, 12 October 2009 (UTC)
Oh, B is short for bender235, I see. --bender235 (talk) 15:48, 12 October 2009 (UTC)

William M. Connolley, could you please reason your objection? As far as I can see you demanded an "if-then" phrasing, which there is now. --bender235 (talk) 16:04, 17 October 2009 (UTC)

See my comment of 20:38, 11 October 2009 above, which restates earlier comments. Why do I have to say this again? William M. Connolley (talk) 18:23, 17 October 2009 (UTC)
...which means you consider this information useless, but User:ThuranX and me do not. That's actually a majority for having this information in the article, but let's conduct a broader poll by adding it again with {{off-topic?}}. --bender235 (talk) 12:09, 18 October 2009 (UTC)
No, William is right. Extrapolation from published info is original research. Just stick to what the sources say. Dicklyon (talk) 15:39, 18 October 2009 (UTC)
Curry (2008), p. 35: "Assuming that the AMO continues with a 70-year periodicity, the peak of the next cycle would be expected in 2020 (70 years after the previous 1950 peak)."
My addition: "Assuming that the AMO continues with its quasi-cycle of roughly 70 years, the peak of the current warm phase would be expected in c. 2020 (after peaks in c. 1880 and c. 1950)."
Could you please show me the "extrapolation" and "original research"? --bender235 (talk) 22:31, 18 October 2009 (UTC)
This puts far too much weight on the 70-year figure, when (like most such oscillations) the actual period is not so regular. See e.g., Dijkstra et al. 2006[3], Gray et al. 2004[4] and other referencs where you will find the period variously stated as 50 to 70 years, 60 to 100 years, and so on. Short Brigade Harvester Boris (talk) 22:49, 18 October 2009 (UTC)
True, but that's why the sentence says "Assuming there is a 70-year cycle…". And at least two sources back that assumption. --bender235 (talk) 23:18, 18 October 2009 (UTC)

Now that there's at least one source that extrapolates it, we should find an appropriate place in the article for it. The lead is probably not the best place, given the marginal validity and relevance of the extrapolation, in light of other sources that would put the range of peak years overlapping the current time. Dicklyon (talk) 23:11, 18 October 2009 (UTC)

Okay, it does not have to be in the lead. But it should definitely be in this article somewhere. --bender235 (talk) 23:18, 18 October 2009 (UTC)
No. It places unjustifiable weight on the 70-year figure. Doing so neglects (indeed, misrepresents) one of the most important aspects of the AMO, which is that its variable nature presents a challenge in using it for predictive purposes. Short Brigade Harvester Boris (talk) 23:32, 18 October 2009 (UTC)
As long as it's done in a way the that doesn't put undue emphasis on 2020, and allows the prediction to span 2000–2040, I would think it would be OK; maybe the 2020 quote, followed by a tempering statement from the other source? Dicklyon (talk) 01:20, 19 October 2009 (UTC)

Article probation[edit]

Please note that, by a decision of the Wikipedia community, this article and others relating to climate change (broadly construed) has been placed under article probation. Editors making disruptive edits may be blocked temporarily from editing the encyclopedia, or subject to other administrative remedies, according to standards that may be higher than elsewhere on Wikipedia. Please see Wikipedia:General sanctions/Climate change probation for full information and to review the decision. -- ChrisO (talk) 15:58, 2 January 2010 (UTC)

What theories are there as to the length of the AMO[edit]

The article defines the AMO and its effects. Can we say anything about what causes the (noisy) cycle and why it should be about 70 years ? Rod57 (talk) 02:55, 15 January 2010 (UTC)

I don't think there's a single accepted mechanism yet. Knight et al (2005, GRL) argue based on AOGCM results that it results from an unforced oscillation of the Atlantic thermohaline circulation. Dima and Lohmann (2007, J. Cli.) propose that it is caused by an atmosphere-ocean-sea ice interaction. In their mechanism atmosphere-ocean coupling in the North Pacific amplifies a circulation anomaly that affects the export of Arctic ice through the Fram Strait (east of Greenland). Changes in sea ice export then affect North Atlantic salinity and thus the strength of the thermohaline circulation. The mechanisms in these two articles could be consistent with one another, though AOGCMs don't usually do a good enough job with sea ice to pick up on things like the coupling that Dima and Lohmann propose. Short Brigade Harvester Boris (talk) 03:15, 15 January 2010 (UTC)
Thanks. That would make a great addition to Atlantic multidecadal oscillation#Mechanisms. Rod57 (talk) 03:46, 15 January 2010 (UTC)

Same as Tropical Multidecadal Oscillation?[edit]

In the latest NOAA update there is a mention to "Tropical Multidecadal signs".

Anybody can confirm whether these the same as the AMO?

If so, given the importance of NOAA jargon, I believe a redirect should be created for Tropical Multidecadal Oscillation

MOUNTOLIVE fedeli alla linea 21:29, 22 August 2010 (UTC)


We say:

Their histogram of zero crossing intervals from a set of five re-sampled and smoothed version of Gray et al (2004) index together with the Maximum Likelihood Estimate gamma distribution fit to the histogram, showed that the largest frequency of regime interval was around 10–20 year... Assuming that the AMO continues with its quasi-cycle of roughly 70 years

which makes little sense. Is the period 10-20 years or 70? William M. Connolley (talk) 11:33, 14 November 2011 (UTC)