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I disagree that there is no cycle involved with the AMO as the graph below demonstrates, as for misleading with false information then attributing melt water from Greenland with nothing more than scant theories and no factual data is very misleading. Now if we were to agree on that being a possibility then I would agree otherwise its straw clutching at best.

 

2000px-Atlantic_Multidecadal_Oscillation

 

I'm not trying to claim there is no cycle or that it's not related, but that it's not regular enough to claim anything with confidence. While there are different versions of the AMO out there, that graph shows little pattern before 1930, a positive period roughly from 1930 to 1960, and -ve period then from 1960 to 2000. There just isn't enough data to establish a regular length of -ve or +ve phases. Even if we take the last 2 phases as being the reality of the AMO and ignore the rest, then we should expect this positive phase to last until about 2030. As it is, we can't even be sure if the cold pool and the AMO are related. Remember, the AMO is a measure of the entire North Atlantic SSTs, while the cold pool only occupies a small fraction of that.

 

Now, they may be related, it's silly to dismiss the idea, but it's equally silly to dismiss other factors on the basis that it's just the AMO doing what it does.

 

The proposed link between the melting ice on Greenland and the cold pool (and slow down in the AMOC) is based on published peer reviewed studies using decades of observational data and expert knowledge. The studies have been posted and discussed on this thread earlier. They may well be wrong, of course, but for now, it's worth considering all possibilities.

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So, have you ever wondered how exactly would N Atlantic look like if you would pump out all the water? Well, its one big mountain range (MAR - Mid Atlantic Ridge). It gives you a feeling and a differe

Yeah, I think that's quite a disingenuous chart (no reflection on yourself , of course!).   If we look at the months used in that chart, and the 9 months leading up to them, we get the following:  

The 13 hours later this arrived..   Many thanks for your enquiry regarding North Atlantic sea surface temperatures. I have spoken to the relevant scientists within the Met Office Hadley Centre who h

Posted Images

The graph is False?  I don't think so knocker,  a point of view may be right or wrong for sure, but the information of the graph isn't and could be relevant . If I'm guilty of anything it's not finding/posting the link you provided [which you do well on regular basis] of the same graph but the aim was the graph and its information.  I do however, believe that big variability displays a natural side more at play....my opinion again until concrete proof gets achieved either way.

 

I didn't say the graph was false just that you were posting false information based on the graph when you accompanied the graph with this.

 

 

Aiding or not.......doesn't seem to be down to excessive ice melt from Greenland

 

On it's own the graph isn't relevant to ice melt as it doesn't include the 200-300Gt/year due to calving. Of course everyone is entitled to a point of view but it needs to be on all of the facts not conveniently selected ones. That's why Felix posted it on it's own in the first place.

Edited by knocker
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I'm not trying to claim there is no cycle or that it's not related, but that it's not regular enough to claim anything with confidence. While there are different versions of the AMO out there, that graph shows little pattern before 1930, a positive period roughly from 1930 to 1960, and -ve period then from 1960 to 2000. There just isn't enough data to establish a regular length of -ve or +ve phases. Even if we take the last 2 phases as being the reality of the AMO and ignore the rest, then we should expect this positive phase to last until about 2030. As it is, we can't even be sure if the cold pool and the AMO are related. Remember, the AMO is a measure of the entire North Atlantic SSTs, while the cold pool only occupies a small fraction of that.

 

Now, they may be related, it's silly to dismiss the idea, but it's equally silly to dismiss other factors on the basis that it's just the AMO doing what it does.

 

The proposed link between the melting ice on Greenland and the cold pool (and slow down in the AMOC) is based on published peer reviewed studies using decades of observational data and expert knowledge. The studies have been posted and discussed on this thread earlier. They may well be wrong, of course, but for now, it's worth considering all possibilities.

I think we're got crossed wires as I'm not dismissing it as its still a possibility but on the little evidence we do have it appears to purely natural. I think we do need more data one way or the other to confirm this.
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Yep - agree with Knocker. I like to be as open minded as possible with regards to aspects of AGW... but I would also like to see your evidence that the Greenland ice melt is slowing down MIA. 

 

CH and Knocker

 

I said that the information was contained on the DMI site. (greenland section)

 

Link here

 

http://beta.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/

 

Basically it consists of a series of maps and graphs which show for the last melt season that the balance has increased a small amount.

 

It also shows maps that indicate that the re-freeze is going at the fastest rate they have seen. (seasons start Sept 1st on here)

 

I am not claiming it is critical one way or the other, but my point was 'is it coincidence that the greenland ice mass balance has stopped dropping at the same time as the Arctic sea ice is increasing at its fastest rate for at least 10 years and all this when we have an abnormal pool of cold water in the Atlantic'. The answer is that no one knows.

 

 

Separate subject, but I too feel BFTV's post above is a good summation of where we stand today.

 

I feel however that the graphs supplied by BFTP do show that following many years of uplifts that the AMO appears to be at its peak and for the last 5 years has been slowly declining. Is this the start of the major fall in Atlantic temperatures anomalies or, is it,  as occured in the 1940's a hiatus on its way to the final peak? The latter is possibly more likely if it is a genuine 30 - 35 year cycle as does appear to be the case from the data.

 

It certainly, to me,  appears that at  it has to be clear that  it is not going to be a driver of warmth for too much longer or at all for the next 50 years.!

 

MIA

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Looks like the cold pool, at least at the surface, is continuing to fade.

 

Below is a animation of weekly SST anomalies from mid July up to the week on Oct 12-19th.

 

hbGpLSm.gif

I  vaguely remember you saying something on the lines of this could happen as we approach November and then reappear during  the winter months?

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I  vaguely remember you saying something on the lines of this could happen as we approach November and then reappear during  the winter months?

 

I think that was the trend in the AMO, in recent years it tended to peak in the summer/early Autumn and then drop into the Winter and Spring.

 

bY3fPmI.png

 

We don't really know what the cold pool will do, but some suggested that the extra cold water in the sub surface means it could re-strengthen during the winter.

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CH and Knocker

 

I said that the information was contained on the DMI site. (greenland section)

 

 

As already stated that doesn't include calving so doesn't represent the total melt. Anyway a recent paper on the subject.

 

Elevation change of the Greenland ice sheet due to surface mass balance and firn processes, 1960–2013

 

Abstract. Observed changes in the surface elevation of the Greenland ice sheet are caused by ice dynamics, basal elevation change, surface mass balance (SMB) variability, and by compaction of the overlying firn. The latter two contributions are quantified here using a firn model that includes compaction, meltwater percolation, and refreezing. The model is forced with surface mass fluxes and temperature from a regional climate model for the period 1960–2013. The model results agree with observations of surface density, density profiles from 62 firn cores, and altimetric observations from regions where ice-dynamical surface height changes are likely small. We find that the firn layer in the high interior is generally thickening slowly (1–5 cm yr−1). In the percolation and ablation areas, firn and SMB processes account for a surface elevation lowering of up to 20–50 cm yr−1. Most of this firn-induced marginal thinning is caused by an increase in melt since the mid-1990s, and partly compensated by an increase in the accumulation of fresh snow around most of the ice sheet. The total firn and ice volume change between 1980 and 2013 is estimated at −3900 ± 1030 km3 due to firn and SMB, corresponding to an ice-sheet average thinning of 2.32 ± 0.61 m. Most of this volume decrease occurred after 1995. The computed changes in surface elevation can be used to partition altimetrically observed volume change into surface mass balance and ice-dynamically related mass changes.

 

http://www.the-cryosphere-discuss.net/9/3541/2015/tcd-9-3541-2015.html

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As already stated that doesn't include calving so doesn't represent the melt. Anyway a recent paper on the subject.

 

Elevation change of the Greenland ice sheet due to surface mass balance and firn processes, 1960–2013

 

http://www.the-cryosphere-discuss.net/9/3541/2015/tcd-9-3541-2015.html

 

How did I know you would come back with calving? Do you know how much has calved in the last 6 months? Where is the  data that shows calving has dominated the growth this year?

 

The data shown does represent the difference between snow fall and snow melt, which has been negative for many years. It is the first year on record that I have seen that it has happened.

 

How can we dismiss any data when we do not understand what  is currently happening?

 

Is the increased snow accumulation the result of the colder Atlantic waters and temperatures as I asked? Or - is it due to calving?

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............. (snipped).......

 

This has been a fascinating and informative thread so far. While it's highly unlikely that a bunch of amateurs on a weather site will solve this puzzle, I think we should be open to, and could benefit from, discussing all possibilities, ideally with evidence and sound reasoning.  :drinks:

 

Great post BFTV.

 

I  vaguely remember you saying something on the lines of this could happen as we approach November and then reappear during  the winter months?

 

I thought it might be worth me posting my graph again. It shows the Monthly Mean SST for the cold pool area (as identified earlier in this thread by BFTV) for the last few years. But this time I've added the long-term mean (1948 - 2015) to give a better idea of how recent years & months compare with the long-term 'average'.

 

You will see that for 2012 and 2013 nearly every month's SST was above the long-term. In 2014 nine months were below the long-term with the exceptions being Aug, Sep & Oct. However, so far in 2015, every month has been below the long-term, which is why the anomaly has remained 'colder than normal' all year.

 

post-20040-0-55890200-1445537048_thumb.j

 

I will update the graph again when October's data is available. Will it stay below the long-term or does BFTV's animated graphic above suggest otherwise?

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How did I know you would come back with calving? Do you know how much has calved in the last 6 months? Where is the  data that shows calving has dominated the growth this year?

 

The data shown does represent the difference between snow fall and snow melt, which has been negative for many years. It is the first year on record that I have seen that it has happened.

 

How can we dismiss any data when we do not understand what  is currently happening?

 

Is the increased snow accumulation the result of the colder Atlantic waters and temperatures as I asked? Or - is it due to calving?

 

Cold waters wouldn't result in increased snow as colder air holds less moisture. It is expected that more snow will fall over Greenland during winter half of the year, as warming air temperatures (while still well below 0C) will result in more moisture in the air and more snowfall, increasing the surface mass balance. Much of the waters around Greenland are warmer than average at the moment anyway as the cold pool has generally remained south of Iceland.

 

We see a similar thing in Antarctica, where East Antarctica (high elevation, very cold) is gaining ice due to increased snowfall, while Western Antarctica (lower elevation, more similar to Greenland) is losing ice overall due to melting and extra glacier calving. Both still gain mass during their winter season, but the melt season and calving help determine the overall mass change.

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I  vaguely remember you saying something on the lines of this could happen as we approach November and then reappear during  the winter months?

If you look at the cold pool during 2009 (I think the last time we had a tripole in the Atlantic ) it was very cold right up to October where it faded, then restablished in November, then we had the very cold start to winter

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If you look at the cold pool during 2009 (I think the last time we had a tripole in the Atlantic ) it was very cold right up to October where it faded, then restablished in November, then we had the very cold start to winter

 

Yes, a big difference between September and October of that year. Here's September, October and November on the IMO SST anomaly charts. One must regard every year as unique - no guarantee it will be the same this year.

 

Sep  era-i_nat_msl-mm_ci-mm_sst-anom_200909.p  Oct  era-i_nat_msl-mm_ci-mm_sst-anom_200910.p  Nov  era-i_nat_msl-mm_ci-mm_sst-anom_200911.p

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Yes, a big difference between September and October of that year. Here's September, October and November on the IMO SST anomaly charts. One must regard every year as unique - no guarantee it will be the same this year.

 

Sep  era-i_nat_msl-mm_ci-mm_sst-anom_200909.p  Oct  era-i_nat_msl-mm_ci-mm_sst-anom_200910.p  Nov  era-i_nat_msl-mm_ci-mm_sst-anom_200911.p

Yes and the cold pool became even colder in December that year. So a keen eye on the cold blob during November, I would bet on it coming colder again towards the end of the year

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I've said it before and I'll say it again...it's been relatively calm over the last few weeks,wouldn't that lack of mixing of the water column result in a natural increase in SST?

As the more mobile air starts to come through over the next week or two the warming on the surface may well dissipate. Maybe?

Edited by JeffC
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This thread has been highly informative and enjoyable to read with each one of us offering different theories on why the cold pool has developed, and the best thing it's been discussed in civilised manner. Great stuff everyone.

Edited by Hocus Pocus
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Well while the cold pool remains, it might be worth noting that the research overwhelmingly suggests that it encourages a positive winter NAO with a more northern and stronger storm track pushing further into Europe. Coldies could be backing the wrong horse.

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Well while the cold pool remains, it might be worth noting that the research overwhelmingly suggests that it encourages a positive winter NAO with a more northern and stronger storm track pushing further into Europe. Coldies could be backing the wrong horse.

I read that also but I would think that the strength of the Northern arm of the jet would be governed by events over the other side of the pond?
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Well while the cold pool remains, it might be worth noting that the research overwhelmingly suggests that it encourages a positive winter NAO with a more northern and stronger storm track pushing further into Europe. Coldies could be backing the wrong horse.

 

I guess, as with some of the conflicting research papers we've discussed in this thread, there are conflicting views about the impact of the cold pool. Here's a winter forecasts from theweatheroutlook.com that suggest other factors (ENSO, QBO, etc) could well drive a milder winter, but mention the cold N. Atlantic anomaly as one of the few factors that could support a colder winter.

 

2) Sea Surface Temperatures (SSTs) in the North Atlantic.

Temperatures to the west of the UK and south of Greenland are below average. This may reduce mobility across the Atlantic. Possibly favours a colder winter.

http://www.theweatheroutlook.com/twoother/twocontent.aspx?type=hpnews&id=2862&title=UK+winter+2015%2F16+outlook

 

And ukweatherforecast.co.uk have this comment in their winter forecast:

 

Another interesting variable is the continued negative sea temperature anomalies to the west of the UK, within the North Atlantic. The generally poor summer weather, especially regarding temperatures, was attributed, partially, to this cold pool of water. At the moment there is some confidence to suggest that this region of cold temperature anomalies within the North Atlantic will continue through the coming winter and importantly what this may do is make any westerly or north-westerly winds somewhat colder across the UK than normal. The reason for this is that usually cold arctic air that gets filtered out of Eastern Canada or Greenland, is often modified and ‘made warmer’ by the relatively warm North Atlantic sea temperatures by the time it reaches the UK. Clearly if the North Atlantic sea temperatures are colder than average and set to remain so through the coming winter, then, in theory, any west or north-westerly winds may well be colder than would normally be expected from a source over the North Atlantic. This may well aid in lowering the overall average temperature for the winter period and more particularly once we get into January and February.

 

Of course they could just mean colder rain from the W/NW!! But on a more positive note, a degree or two colder and some marginal events could mean snow rather than cold rain, particularly for folk up north!

 

(Footnote: Tried to post the second link and got this message: You have entered a link to a website that the administrator does not allow links to. Why??)

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Just a question to put out there. Does anyone know if we have had a snowy cold winter (not just the north uk) from a predomatley west/north west storm track with little in the way of blocking, due to a cold anomaly in the North Atlantic??Winter 1984/85 comes to mind, I'm sure I heard from somewhere that it was a cold, snowy winter predomatley from west/north west.post-17869-0-30235500-1445634795_thumb.j

And sure enough that year ended with a cold Atlantic

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Just a question to put out there. Does anyone know if we have had a snowy cold winter (not just the north uk) from a predomatley west/north west storm track with little in the way of blocking, due to a cold anomaly in the North Atlantic??Winter 1984/85 comes to mind, I'm sure I heard from somewhere that it was a cold, snowy winter predomatley from west/north west.attachicon.gifimage.jpg

And sure enough that year ended with a cold Atlantic

can't be absolutely certain on dates but I do remember in the late 70's early 80's there being snow showers from the NW country wide not sure about frontal snow though? I think it probably stands to reason that if the north atlantic is cooler than normal that there is a higher probability than normal of colder conditions affecting us from a more westerly quarter, lets wait and see.......................

Edited by Mark Parsons
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Just published this month, Competition between global warming and an abrupt collapse of the AMOC in Earth’s energy imbalancehttp://www.nature.com/articles/srep14877#f2 (open access) and reported here - Could ‘the Day After Tomorrow’ really happen?http://geographical.co.uk/nature/climate/item/1337-could-the-day-after-tomorrow-happen which links to the RAPID site.

 

Interesting stuff, a model simulation with ice melt freshwater hosing from 2000 onwards shows AMOC affecting pretty much all NH so reducing global mean temperature and cancelling AGW for a couple of decades after around 15 years (ie 2015 or about now) -

Abstract

A collapse of the Atlantic Meridional Overturning Circulation (AMOC) leads to global cooling through fast feedbacks that selectively amplify the response in the Northern Hemisphere (NH). How such cooling competes with global warming has long been a topic for speculation, but was never addressed using a climate model. Here it is shown that global cooling due to a collapsing AMOC obliterates global warming for a period of 15–20 years. Thereafter, the global mean temperature trend is reversed and becomes similar to a simulation without an AMOC collapse. The resulting surface warming hiatus lasts for 40–50 years. Global warming and AMOC-induced NH cooling are governed by similar feedbacks, giving rise to a global net radiative imbalance of similar sign, although the former is associated with surface warming, the latter with cooling. Their footprints in outgoing longwave and absorbed shortwave radiation are very distinct, making attribution possible.

 

Regionally however, including the UK the effect is greater -

 

It is evident from Fig. 7b that it takes several decades for the NH to recover, with areas over the ocean and northwest Europe where recovery takes more than a century. In an elongated band along the eastern North Atlantic a hiatus period may even exceed 200 years.

 

Maps show dramatic cooling - http://www.nature.com/articles/srep14877/figures/2

 

post-2779-0-67952100-1445758592_thumb.gi

 

But hold on a minute, the north Atlantic freshwater hosing is a permanent 1 SV per annum which is over 8.5 cm sea level rise per year compared to the current 3mm/yr or less from all sources and a steric warming expansion, and another look at the temperature chart shows drastic cooling over Greenland within 15 years from the start of hosing which would prevent melting at even today's levels. Unfortunately the public perception and zeitgeist is coloured by the headline abstract and theoretical potential, not the realistic likelihood, surely this research would be better including actual probable hosing?

 

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