Jump to content
Sign in to follow this  
Surrey

Cooler Atlantic

Recommended Posts

And another paper on the same topic, using actual in situ data rather than inferred satellite based estimates.

 

Observing the Atlantic Meridional Overturning Circulation yields a decade of inevitable surprises

 

over the period of the 26.5°N observations, the AMOC has been declining at a rate of about 0.5 Sv per year, 10 times as fast as predicted by climate models. Whether this is a trend that is a decline due to global warming or part of the so-called Atlantic Multidecadal Oscillation/Variability, inferred from sea surface temperature measurement, is also a subject of active research. There is no doubt that continuously observing the AMOC over a decade has considerably altered our view of the role of ocean variability in climate.

 

This article looks at the RAPID Array (the instruments used to measure the "Gulf Stream") and the results they've gotten so far.

http://www.carbonbrief.org/blog/2015/06/the-atlantic-conveyor-belt-and-climate-10-years-of-the-rapid-project/

 

screenshot-2015-06-19-181023_574x210.jpg

 

 

screenshot-2015-06-19-183221_575x469.jpg

Share this post


Link to post
Share on other sites

BFTV...

 

So the change is a real actual measurable fact in data and not just a 'modelled' one.

 

This is beginning to bring back my confidence in climate science!

 

Where will it take us?

 

The models suggest a cooling of 'Atlantic' based continents and continental shelves as a fairly quick consequence. Many may well be happy to hear this news?

 

The effects reported as a difference of 10 times for the transfer of heat difference in the actual RAPID array, whereas the reported changes according to the models quote figures as high as 100 times for the maximum effect that was possible compared to current climate models. The rapid array is pretty well south in the north Atlantic and may well still be recording the water trying to pump northwards from the south . I wonder what it is say at our latitude?

 

If this large amount of heat from the south/equatorial areas does not move northwards what will happen to it? Will it remain on the surface and create havoc in the southern hemisphere, or will it be driven deep into the very cold southern oceans below 2000 meters probably for thousands of years, or even undercut the cold North Atlantic at similar depths?

 

PS Note I recognize it is all still speculation as a 'changing' point may well be reached when the AMO decides its had enough and returns to its age old pattern of 'burning' up the Arctic ice.

 

I guess it will all depend upon whether what we are seeing is as a result of ongoing northern ice melt-waters  or as a one off natural blip. I am still convinced that the AMO is having an ongoing effect that is present in the historical data, with about a 60 yearish cycle. But does the additional melting ice effect described above mean we have entered into a 'tipping point' into a new climate, but with the aid of the natural cycle of the AMO?

 

Sure is an interesting time to be an oceanographer or even a speculator like me? :D :D :D

 

All from me for now as I am away for a  couple of days.

 

MIA

.

Share this post


Link to post
Share on other sites

The paper has been discussed at RC here (by the main author himself, I believe):

 

http://www.realclimate.org/index.php/archives/2015/03/whats-going-on-in-the-north-atlantic/

 

Thanks for that link. Interesting to read Prof. Stefan Rahmstorf himself discussing the paper and answering some of the questions in the 3 pages of Q&A that followed. There were several interesting comments/insights from him:

  • Most global climate models do not (yet) include continental ice sheet (meltwater impact) models. 

     

  • A 10% weakening of the AMOC has a 1,000 times larger effect on the heat budget of the N. Atlantic region than the impact of the cold meltwater from Greenland itself.

     

  • You can't put a figure on the atmospheric CO2 ppm limit for an AMOC shutdown, because this risk very much also depends on the speed at which atmospheric CO2 and temperature ramp up – the faster it happens, the more it affects the AMOC. 

 Slightly off topic, but there was also a link out to the blog of co-author Jason Box which contained this comment from him:

 

"There is evidence (two most recent of a growing list of citations) of Artic warming slowing the jet stream, causing it to meander more, creating sticky weather patterns. Welcome to the new abnormal."

Share this post


Link to post
Share on other sites

Might have to adjust those stormy autumn predictions!   http://www.weatherweb.net/wxwebtv2.php

 

Hi lassie. I do enjoy the Webweather TV forecasts. Always something of interest and with all the letters after his name I guess Dr. Keeling knows a thing or two! But nonetheless I think he might be wrong with his conclusions about the cold pool in the N. Atlantic (NA).

 

My reasoning is as follows. Looking back at the NA SST's there have always been notable variances from month to month, so it would suggest we can take waxing and waning of the anomaly as a frequent occurrence. Also notable is that it seems to be a regular occurrence that the negative anomaly weakens at this time of the year, before picking up again later. (So the longer term trend is the one to watch).

 

Here are some SST Anomaly charts from Unisys for the last two years that illustrate this point. I've shown the June anomaly to show the cold SST's that were in place, and then the August anomaly to show the late summer 'warm-up', and finally the Dec anomaly showing the colder SST's re-establishing. 

 

2013. June post-20040-0-76428200-1442065461_thumb.g Aug post-20040-0-04410500-1442065476_thumb.g Dec post-20040-0-14894300-1442065496_thumb.g

 

2014. June post-20040-0-26807700-1442065524_thumb.g Aug post-20040-0-37517700-1442065535_thumb.g Dec post-20040-0-63111200-1442065554_thumb.g

 

Time will tell whether the cold pool is indeed starting on the path to dissipating, but based on the last couple of years we should be very cautious about jumping to conclusions.

 

By the way, in the latest anomaly (11th Sept), not only is the cold pool showing signs of growing again, but there are notable cold SST's developing and moving down the Newfoundland and Labrador coast.

 

11th Sept 2015 post-20040-0-02698500-1442067939_thumb.g

Share this post


Link to post
Share on other sites

Hi lassie. I do enjoy the Webweather TV forecasts. Always something of interest and with all the letters after his name I guess Dr. Keeling knows a thing or two! But nonetheless I think he might be wrong with his conclusions about the cold pool in the N. Atlantic (NA).

 

My reasoning is as follows. Looking back at the NA SST's there have always been notable variances from month to month, so it would suggest we can take waxing and waning of the anomaly as a frequent occurrence. Also notable is that it seems to be a regular occurrence that the negative anomaly weakens at this time of the year, before picking up again later. (So the longer term trend is the one to watch).

 

Here are some SST Anomaly charts from Unisys for the last two years that illustrate this point. I've shown the June anomaly to show the cold SST's that were in place, and then the August anomaly to show the late summer 'warm-up', and finally the Dec anomaly showing the colder SST's re-establishing. 

 

2013. June attachicon.gifsst_anom-130623 23Jun13.gif Aug attachicon.gifsst_anom-130825 25Aug13.gif Dec attachicon.gifsst_anom-131229 29Dec13.gif

 

2014. June attachicon.gifsst_anom-140601 01Jun14.gif Aug attachicon.gifsst_anom-140831 31Aug14.gif Dec attachicon.gifsst_anom-141228 28Dec14.gif

 

Time will tell whether the cold pool is indeed starting on the path to dissipating, but based on the last couple of years we should be very cautious about jumping to conclusions.

 

By the way, in the latest anomaly (11th Sept), not only is the cold pool showing signs of growing again, but there are notable cold SST's developing and moving down the Newfoundland and Labrador coast.

 

11th Sept 2015 attachicon.gifsst_anom Sept11 2015.gif

He was at first thinking that the cold pool would stick around and was going to base his winter forecast around this, then he saw the change that took place recently. He is going to keep an eye on the situation. You could contact him, I think, he is quite open to discussions and comments.

Share this post


Link to post
Share on other sites

If I remember correctly there was high pressure to our west around the start of September, so I wonder if calmer conditions there enabled some slight surface warming before more unsettled weather mixed the water up again and the cold anomaly re-strengthened a bit.

 

Just an idea and I'm not sure if the sea would have become calm enough out there but I know such occurs in the seas around the UK during calm summer spells, with surface stratification enabling sea surface temperatures to exceed 20C locally in the open ocean off the SW in 2014.

Share this post


Link to post
Share on other sites

He was at first thinking that the cold pool would stick around and was going to base his winter forecast around this, then he saw the change that took place recently. He is going to keep an eye on the situation. You could contact him, I think, he is quite open to discussions and comments.

 

Thanks lassie. I've applied to join their forum and will try and contact him to discuss. 

Share this post


Link to post
Share on other sites

First half of the video is about sea temperatures, second half would be more  suited to the autumn thread. http://www.weatherweb.net/wxwebtv2.php

 

Interesting that he now talks about the cold pool without a mention of it dissipating. Also talks about the cold pooling in both North and South Atlantic as being indicative of the AMO turning negative, but is careful to stress that we can't be sure about that or the exact impact. Another enjoyable watch - far more thought provoking than watching a BBC/Met Office forecast!

 

I've submitted my thoughts (along the lines of my post #111 above) this morning. Hopefully I'll get get a response!  

Share this post


Link to post
Share on other sites

I have to say that some of these SST anomaly charts seem a little deceptive. The latest from the NOAA portal.

 

post-12275-0-75562600-1442310750_thumb.j

Share this post


Link to post
Share on other sites

I have to say that some of these SST anomaly charts seem a little deceptive. The latest from the NOAA portal.

 

Not sure what you mean by "deceptive" knocker. I don't think the graphics are particularly good on that NOAA chart, compared with the Unisys graphics. But that's a trivial point as we're talking visual impact and personal preference.

 

More relevant, the SST anomaly of -0.8C that the chart shows is the same as the latest value for 2015 shown on my cold pool graph, above. So no discrepancy there if you've input the Lat & Long coordinates for the cold pool to produce that chart? (On that point - I haven't stumbled across the page on the NOAA portal that allows you to produce a chart like that  - I'd be very grateful for the link please. Thks).

 

It's going to be an interesting period tracking the cold pool SST. It's currently lower than the previous 3 years 'low point' and even if it slackens somewhat during Sept/Oct, it would have to be an exceptional increase to stop the Nov/Dec decline reaching a new record low?

Share this post


Link to post
Share on other sites

The unisys SST anomaly chart is certainly much improved since they changed the colour scheme and legend last year. This can be seen from BW's post above:

 

post-20040-0-37517700-1442065535.gif

 

 

post-20040-0-02698500-1442067939.gif

 

 

The former bizarrely repeats the colour scale at regular intervals so you can't tell if the anomaly is cold, near average, or boiling hot. 

Share this post


Link to post
Share on other sites

It is not just visual impact, it is the thirty year period the climatology covers. Most of the NOAA charts are for a period where the AMO was predominately negative - not sure which range in the one posted as they seem to use different bases for different things.

 

The graph for AMO to identify cool periods     amo-english.png

 

I prefer to compare the recent cooling, set against recent climatology and like the Canadian map as it covers this.

 

QINTbYJ.png

 

In the grand scheme of things it is all about where it takes us, not where we have been.

 

Sources.  http://la.climatologie.free.fr/amo/amo-english.htm

                 http://weather.gc.ca/saisons/sea-snow_e.html

 

Share this post


Link to post
Share on other sites

A couple of recent tweets by Philip Klotzbach

 

Philip Klotzbach â€@philklotzbach Sep 11

Salinity values in the far N Atlantic have been dropping recently. Short-term blip or weakening thermohaline?

 

Coherent freshening in the far North Atlantic was associated with last switch from +AMO to -AMO around 1970.

 

Sorry don't know how to copy and paste the animation.

 

Philip Klotzbach â€@philklotzbach Sep 11

How have SSTs changed in the Atl during 2015? Animation shows cold trop Atl warming recently, N Atl remains cold.

post-12275-0-42053400-1442324395_thumb.p

post-12275-0-59518200-1442324407_thumb.p

Edited by knocker

Share this post


Link to post
Share on other sites

A couple of recent tweets by Philip Klotzbach

 

Philip Klotzbach â€@philklotzbach Sep 11

Salinity values in the far N Atlantic have been dropping recently. Short-term blip or weakening thermohaline?

 

Coherent freshening in the far North Atlantic was associated with last switch from +AMO to -AMO around 1970.

 

Sorry don't know how to copy and paste the animation.

 

Philip Klotzbach â€@philklotzbach Sep 11

How have SSTs changed in the Atl during 2015? Animation shows cold trop Atl warming recently, N Atl remains cold.

 

Can't embed either, but here's the link:

 

https://pbs.twimg.com/tweet_video/COoKwIXUwAAty0i.mp4

Share this post


Link to post
Share on other sites

I found an archive of monthly N Atlantic SST anomalies on the Icelandic Met site: gives a nicely detailed picture rather than the broad brush charts we have looked at so far.

 

Some have commented on the similarity between this year and 2009 - an August comparison for both years below.

 

2015  ecmwf_nat_msl-mm_ci-mm_sst-anom_201508.p   2009   era-i_nat_msl-mm_ci-mm_sst-anom_200908.p

Appreciably lower SST's between the UK and Iceland in 2015 than 2009. Also, SST's look lower overall almost everywhere this year.

Interesting.

Share this post


Link to post
Share on other sites

Appreciably lower SST's between the UK and Iceland in 2015 than 2009. Also, SST's look lower overall almost everywhere this year.

Interesting.

 

Quite a lot is being made of this at the moment (especially with respect to certain newspaper headlines for the UK winter), but the overall global pattern of SSTs is quite different. For instance, this year there's a huge warm anomaly on the west coast of Canada, whereas the opposite was true in 2009.

 

anomnight.9.17.2009.gif

 

anomnight.9.17.2015.gif

 

 

 

Also it's worth noting that by Dec 2009 the cold N Atlantic anomaly was much reduced. It remains to be seen what happens this year.

Share this post


Link to post
Share on other sites

Appreciably lower SST's between the UK and Iceland in 2015 than 2009. Also, SST's look lower overall almost everywhere this year.

Interesting.

 

The 2009 profile is a better fit for the Atlantic tripole anomaly that can lead to negative NAO (UKMO research). The question is ... at which point does the overall cooling override that signal?

 

 

Quite a lot is being made of this at the moment (especially with respect to certain newspaper headlines for the UK winter), but the overall global pattern of SSTs is quite different. For instance, this year there's a huge warm anomaly on the west coast of Canada, whereas the opposite was true in 2009.

 

<snipped>

 

Also it's worth noting that by Dec 2009 the cold N Atlantic anomaly was much reduced. It remains to be seen what happens this year.

 

The EUROSIP (amalgam of ensembles from ECM/UKMO/NCEP/MeteoFrance) has the cold pool of similar strength through winter 15/16 and only slightly weakening by March.

 

IMME_tmpsfc_lead4.png

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...