From ICECAP
AMO, The Key Global Climate Indicator By Matt Vooro
The AMO is an ongoing series of long-duration changes in the sea surface temperature of the North Atlantic Ocean, with cool and warm phases that may last for 20-40 years at a time and a difference of about 1F between extremes. These changes are natural and have been occurring for at least the last 1,000 years. [per NOAA].
The AMO index is calculated at NOAAPSD by using the Kaplan SST data set [5×5], determining the area weighted average over the North Atlantic over 0-70N and then detrending this data. The average AMO index or the Atlantic Multidecadal Oscillation index went negative or cool in January 2009 The average for the first 5 months this year is about [-0.06] . It has been cooling since 2003. In the past, the very cold seasons of North America and especially the East coast happened when the annual average AMO went cool [ as low as -0.405] in the 1970’s.
It seems that this level of cool AMO may be several years off as the AMO cooling rate appears to be still slow. Back in 1964 it took about 8 years before the AMO went to [-0.3] by 1971. Review of other periods for similar rates of decline of the AMO show a spread of about 2-8 years. However the solar activity was much higher during 1964-1972 and things may cool down faster currently with extended solar minimum and anticipated low future solar cycles. If AMO does drop faster, then the cold weather like 1964-1979 may be the norm here much sooner and the East Coast will cool down as well as will the globe. The most sustained number of low AMO levels was during the cold spell of 1902 -1925 and again the 1970’s.
The graph below shows how closely Annual Global Air Temperature Anomalies [Crutem3] follow the Atlantic Multidecadal Oscillation Index [AMO] below.
The last interval change was 1994 or about 15 years ago and according to Enfeld et.al (2005), the probability that AMO will switch to cool in 15 years is about 80%. Based on this analysis , there is a high probability that the current cooling phase of AMO which started in 2009 is real and likely sustainable for the next 20 years at least.
The graph below shows the decline of the AMO index from warm to cool between 2005 and 2009 below.
EL NINO 2009-2010
There has been an El Nino within about 12 months after each of the last four solar minimums. The same pattern seems to be developing again now. The El Nino may be a moderate or weak and short lived [about a year]. It may have a minor effect on global temperatures, like in the period 1965-1966 when US temperatures continued to drop despite the El Nino.
AMO appears to be like a thermostat or predictor of global temperatures. ENSO events if moderate or strong seem to modify, amplify or over-ride the AMO effects. This pattern will continue to bring cool yearly temperatures and colder and snowy winters like 2008 and 2009. My best guess is that the climate of the 1960’and 1970’s will be our climate for the next several decades [2-3] at least, and inter-dispersed with periodic warm years. PDO and AMO readings are of limited value for short term use but quite useful and accurate for decadal forecasts. Currently 2009 looks something like 1971 [cool PDO, low cool/ near neutral AMO] and the rest of this decade looks like the 1970’s if you had pick one decade from the past. The 1960’s and the 1950 are also close behind.
This latest period of cooler weather is not the start of some modern ice age or new grand cold minimum but just another cool cycle of the planet that happens about after every 20-30 years more recently when AMO and PDO are both in the cool mode simultaneously. The coldest last such cycle 1902-1925 when AMO hit a single month low of -0.563 and PDO went down to -1.72 and global air temperature anomalies plummeted to -0.581C [crutem3] in 1911. Other such cool periods occurred 1964-1976 and also much earlier during the Dalton and Maunder Minimums. Read more here.
AMO just neutral and UK experienced coldest winter in last 30 years. Imagine if it will go cold. It is very interesting that such tiny temperature anomalies (1F, compared to PDO in whole degrees C) affect the Atlantic area so much; maybe there are changes in air circulation, causing more arctic air to go south.
Oh, did I mention Arctic (ice)?
http://blog.sme.sk/blog/560/195013/arcticamo.jpg
Amo
Amas
Amat
I also think the AMO is one of the major natural climate drivers (along with the ENSO but the AMO seems to have a greater impact than the ENSO).
In June, the AMO increased somewhat to +0.176C after a period of decline where it was as low as -0.114C a few months ago. It appears to be in a long-term downward cycle, but you never know.
Just to see how potentially important the AMO is, have a look at the AMO versus RSS satellite temps – the correlation could just be a coincidence but if you look throughout the entire temperature record going back to the 1870s, there is a similar correlation.
http://img31.imageshack.us/img31/5769/rssvsamo.png
Why start off with a picture comparing July of one year with March of the current? It’s a bit misleading.
Matt Voroo,
Thanks for the article.
The relative warm AMO is what keeps the Europe coastal countries relative warm although last winter was a memorable one.
I have one question:
“This latest period of cooler weather is not the start of some modern ice age or new grand cold minimum but just another cool cycle of the planet that happens about after every 20-30 years more recently when AMO and PDO are both in the cool mode simultaneously”.
That said, what makes you conclude that the recent cooling weather is not a new grand cold minimum?
So is the AMO masking the warming?
hehe Couldn’t resist.
Matt Voroo,
You expect the return of the sixties – seventies weather for the next decades.
I sign for that although my gut tells me it will be colder.
The reason for this is the list of temperature minimum records, many topping cold records dating long before the sixties – seventies weather.
The recent British winter, the braking of century old minimum records in Northern
Europe and late start of summer.
We already observe weather patterns that normally are associated with autumn and winter although we are in the middle of the summer.
I know I am creating a head on collision with a long term observation and a single year of observed weather but I really think something more substantial is going on.
Wow now children in the UK may see a real winter! I remember many cold winters in the 60s and 70s, can’t say that I look forward to them as much now.
This is an outstanding test. If the AMO is heading negative (it certainly appears that way) and the PDO is already negative, that means if the oceans are driving teh climate train like we suspect they are, then we should see temps comparable to the 1960s and 1970s should the AMO/PDO reach similar values.
If yes, then that should absolutely aquit CO2 as a primary driver.
If no, then….hmmm…..
As you’ve said several times Anthony, we live in interesting times…..
Ron De Haan
The ocean temperatures are not quite as cold as they were back during the past cold spells . This can be seen from the difference in ocean temperatures during the cold spell of 1900 -1922, 1960- 1976 and today. The sun has had an extended minimum but I am in no position to say if there will be a substantially extended minimum. So in my judgement the oceans are the prime source of our weather at the moment.
By the way the more significant periods when AMO and PDO were both cold were:
These are approximate periods as the records prior to 1990 are not as good.
1856-1864
1880-1890
1916 -1922 [and also 1909-1911]
1964-1976
I live in the UK and have relatives in many parts of it, who confirm my thoughts; that although last winter was cold by recent standards I don’t think it was the coldest for thirty years – I would put it on a par with 1995-6. Has anyone got the actual figures?
The attached graph illustrates past and current ocean temperatures.
http://data.giss.nasa.gov/gistemp/graphs/Fig.A4.lrg.gif
Matt Vooro: You wrote, “There has been an El Nino within about 12 months after each of the last four solar minimums.”
Are you saying that solar minimums drive El Ninos? Because the coincidence falls apart when you go back further in time. Also, there has been an El Nino within a couple of years of the solar maximums too.
You wrote, “It may have a minor effect on global temperatures, like in the period 1965-1966 when US temperatures continued to drop despite the El Nino.”
I find that sentence confusing because you start with global temperatures and use US temperatures for a two year period to confirm your belief.
Your graph of the AMO versus Global Temperature is somewhat unusual. You’re comparing detrended SST anomalies for the North Atlantic (the AMO) to Global Temperature anomalies that haven’t been detrended.
“Amo
Amas
Amat”
Amamus
Amatis
Amant
Gotta “love it” . . . . 50 years since Father Latravrse pounded Latin into my thick skull and I can still recall the plurals.
Now if I could just remember the name of a person 30 seconds after being introduced.
matt v. (09:05:12) :
Don’t comfort yourself with any relative reassurances of the 1850’s to early 1900’s as being colder. We too can get there and beyond.
1856-1864 was very warm and brought torrential rains to the Western US.
1880-1890 was not so warm for the Western US, though precip was very good.
It’s not so much where we are right now, it’s where we are headed.
According to Unisys there’s currently a nice sized purple spot sitting in the middle of the Atlantic
http://weather.unisys.com/surface/sst_anom.html
It looks like the AMO right now may be close to 0 or a little below looking at that map.
Also on the ENSO front, El Nino is puttering along, but the SOI index has seen a sharp rise into positive territory, that and it seems like the winds shown on the TAO graph as arrows seem to be picking up.
Interesting post but have to agree with MADeluca, the latest SST shows the North Atlantic with much more in the way of warm anomolies comparerd to March. http://www.osdpd.noaa.gov/PSB/EPS/SST/data/anomnight.7.13.2009.gif
Checking out AMSU seems that temperatures are taking off, July’s figures will be very interesting http://discover.itsc.uah.edu/amsutemps/execute.csh?amsutemps+002
The exciting thing to me is that I think there really is an excellent opportunity for “the science to be settled” in the next 5-10 years, one way or the other. . . and maybe even in the next three years. There seems to be a lot of evidence piling up of the “natural variation” heading towards cold. If the AGW factors overwhelm that, then it is time to consider heading for the other camp. If they don’t, it is time for the AGWers to throw in their towels, if not in toto, then at least in serious reconsideration of the future trend line attributable to AGW.
Yes, I know the “return with a vengeance later” crowd will make a rear-guard stand if it comes to that, but I don’t think they’ll be able to make it stick broadly. That’s voodoo not science.
Bob Tisdale
I am not saying that solar events drive El Nino’s but merely making an observation that they did occur after the last four solar minimums. I will leave the why for those who are more knowledgeable about this. Yes I was aware that prior to 1964, the same pattern did not exist. I even posted this fact on a previous WTUT track . Of the last 10 solar minmums , 5 had an El Nino within about 12 months , 3 had it within 2-3 years and 2 had none .
With respect to the 1965-1966 El Nino and its effect on Global and US temperature anomalies , the GISS US ANNUAL SURFACE TEMPERATURE ANOMALY dropped from[ -0.11C] to [-0.25 C] and the ANNUAL GLOBAL CRUTEM3 TEMPERATURE ANOMALY changed only slightly from [-.216 C to [-0.147 C] , a minor warming only as I stated. I just wanted to note that both globally and in US, that particular El Nino, during a cool PDO and a partly cool AMO[1965 ] did not warm things a lot that time . Perhaps my words were not exactly clear.
To compare AMO trends and global temperature anomaly trends, I used the best data available to me. I did not have access to detrended Hadley global temperatures anomaly data. You are right about the difference between the two data sets. I still think there is a pattern here as even Bill Illis’s graph earlier shows.
Bob Tisdale (09:25:25) :
Matt Vooro: You wrote, “There has been an El Nino within about 12 months after each of the last four solar minimums.”
Are you saying that solar minimums drive El Ninos? Because the coincidence falls apart when you go back further in time. Also, there has been an El Nino within a couple of years of the solar maximums too.
If my hypothesis is correct, a lot of those el nino’s following close behind solar minimum will be modoki el ninos. Especially in the onset of oceanic cool phases. Can you spot them in the record Bob? OLR data won’t go any further back than your graph here http://i25.tinypic.com/2035ed.png I guess, but are there other signs they can be recognised by?
Rbateman
You could be right about where we are headed. Certainly the AMO is still nowhere near the past coldest annual levels of -0.4 as in 1974 and the PDO is not down to say -1.95 to -1.8 annually as in 1955-1956, but it was down to -1.29 annually in 2008. The two indices combined [added] were close to the 1970’s level during the past winter[ 5th lowest since the 1950’s] because we had peak monthly cool PDO’S of already -1.76 last year . In 1971 we had a -2.2 monthly peak.Annual PDO’s during the 1970’s reached -1.29 IN 1971, same as 2008
So we were near the cold PDO’s of the 1970’s already in 2008 and early 2009. That is why w have already had so much cool weather in 2008 and 2009.It is the AMO , if it cools like it did before that could cool things even more,plus the accumulative effect of cool weather of many years in a row. However the lows do not always peak at the same time , so there is still some uncertainty.
Matt Vooro,
The strength of the AMO is in a weakening state much like the tropical stratosphere is getting warmer…… A relationship I first touched base on about about four years ago in a lengthy discussion. Which many MET’s have read before.
As far as the El Nino and solar minimum. It’s almost a given but not always, like with 1954-55. But anyone who has been heavily relying upon the sun as a ENSO forecasting mechanism should have a clue as to what factors relate to the forcing of La Ninas or El Ninos.
OT, but: Fred, if you want a trick to remembering names use your existing skills. Conjugate their name as a latin verb, you will never be able to forget it. 🙂
OT. Large climb in tropospheric temperature. http://discover.itsc.uah.edu/amsutemps/execute.csh?amsutemps+002 Expect July UAH and RSS to bounce back up a bit.
It’s well established that regional SST follow weather. So the cooler SST off the east coast of N America probably reflect the recent cool weather.
However, on a global scale the oceans heat the atmosphere for the simple reason the oceans gain large amounts of heat from the sun and the only place it can go is into the atmosphere (and then out into space).
The rate at which this happens varies over years to decades which gives us el ninos, the PDO, etc.
It’s also important to note that almost all the heat in the Earth’s climate system is in the oceans, and cooler SST due to these cyclical variations means the oceans are losing less heat to the atmosphere. Which in turn means the Earth’s climate is getting warmer because less heat is lost to the atmosphere and then space.
Which means atmospheric temperatures to the extent they are driven by SST are negatively correlated with global warming. Warmer atmospheric temperatures mean the Earth’s climate is cooling and visa versa.
Pielke senior discusses climate heat gain below.
http://www.climatesci.org/publications/pdf/R-334.pdf