Flow of Deep Water South from Greenland More ‘Diffuse’ than Previously Thought
Posted by jennifer, May 17th, 2009 - under News, Opinion.
Tags: Climate & Climate Change
WE live on one planet and all its oceans are connected with meridional overturning circulation (MOC) facilitating the mixing of waters across the globe.
In the apocalyptic movie ‘The Day After Tomorrow’ the melting of the polar icecaps disrupts a component of this system, the North Atlantic current, and so North America freezes over with US citizens pouring into Mexico to escape the freezing conditions.
New findings, published late last week in the journal Nature don’t dispute MOC, but suggest that the southern flow of deep water from Greenland may not follow as neat a path as assumed – including by the scientist in the Hollywood blockbuster. In particular rather than the deep water moving as a conveyor belt – yes that is the term that had been used to describe the flow of water southwards – it may be more diffuse.
One of the authors of the new paper in Nature, Amy Bower, has described it as “A swath in the wide-open, turbulent interior of the North Atlantic” rather than a conveyor belt.
In the media release accompanying the publication of the findings, another author Susan Lozier, suggests this means it is going to be more difficult to measure climate signals in the deep ocean.
**********************
Notes and Links
Interior pathways of the North Atlantic meridional overturning circulation
Amy S. Bower, M. Susan Lozier, Stefan F. Gary & Claus W. Böning
Nature 459, 243-247 (14 May 2009) | doi:10.1038/nature07979; Received 24 April 2008; Accepted 5 March 2009
Abstract: To understand how our global climate will change in response to natural and anthropogenic forcing, it is essential to determine how quickly and by what pathways climate change signals are transported throughout the global ocean, a vast reservoir for heat and carbon dioxide. Labrador Sea Water (LSW), formed by open ocean convection in the subpolar North Atlantic, is a particularly sensitive indicator of climate change on interannual to decadal timescales1, 2, 3. Hydrographic observations made anywhere along the western boundary of the North Atlantic reveal a core of LSW at intermediate depths advected southward within the Deep Western Boundary Current (DWBC)4, 5, 6, 7, 8, 9. These observations have led to the widely held view that the DWBC is the dominant pathway for the export of LSW from its formation site in the northern North Atlantic towards the Equator10, 11. Here we show that most of the recently ventilated LSW entering the subtropics follows interior, not DWBC, pathways. The interior pathways are revealed by trajectories of subsurface RAFOS floats released during the period 2003–2005 that recorded once-daily temperature, pressure and acoustically determined position for two years, and by model-simulated ‘e-floats’ released in the subpolar DWBC. The evidence points to a few specific locations around the Grand Banks where LSW is most often injected into the interior. These results have implications for deep ocean ventilation and suggest that the interior subtropical gyre should not be ignored when considering the Atlantic meridional overturning circulation.
http://www.nature.com/nature/journal/v459/n7244/full/nature07979.html
Study finds surprising new pathway for North Atlantic circulation
http://www.eurekalert.org/pub_releases/2009-05/whoi-sfs051309.php
SJT wrote:
“It does note that the MOC has indeed shut down in the past, so we know it is not unknown for climate change to do just that.”
SJT, who are you trying to fool? They do say that MOC has shut down in the past but it is your clever way of twisting their words when you add: “so we know it is not unknown for climate change to do just that”
That doesn’t follow from what they said as they have no evidence that the MOC shut down AS A RESULT of climate change. They do speculate that the current climate change could affect the MOC but they have no evidence that this was the cause in the past. It is your deduction by making the causal relationship with your “so”. Sure, a shut down of the MOC will affect the N European weather but that climate change is the cause of past shut downs is not established, as far as I can ascertain. Please feel free to correct me by showing me the scientific evidence ( a peer reviewed paper on the subject will do).
“Are you talking about going for a picnic or putting yourself at the mercy of the elements?
Are you talking about correct barometric pressure, wind strength and direction, sea conditions etc or just that the sun is shining?
Because if you are depending on forecasts in serious situations and you don’t have plan B ready, you are a mug.”
You are not debating the point. The point is, does the quality of the weather forecasts we get indicate a good understanding of the how the weather works. It does, we get excellent quality compared to 30 years ago. If you want to meander off into some other debate, feel free.
“SJT, who are you trying to fool? They do say that MOC has shut down in the past but it is your clever way of twisting their words when you add: “so we know it is not unknown for climate change to do just that””
I’m not trying to fool anyone, if I have misunderstood what they were saying, so be it. The point is, the CSIRO did not want the current climate science to be associated with TDAT, they gave their reasons for saying so, and what they think the current understanding of the MOC is.
SJT: “They work on the basis that if you have this much CO2, this much sunlight, this much land here, this much water there, etc, what do I come up with? The weather will not match, but if the models are right, the climate, which is the averaged weather, will be right.”
SJT, you should read what Henk Tennekes wrote. That will teach you some humility with regards to your proclamations that the models “will be right”.
The next paragraphs by Henk Tennekes I copied from http://climatesci.org/2009/01/ to make it easy on you:
“A climate model, however, has to deal with the entire climate system, which does include the world’s oceans. The oceans constitute a crucial slow component of the climate system. Crucial, because this is where most of the accessible heat in the system is stored. Meteorologists tend to forget that just a few meters of water contain as much heat as the entire atmosphere. Also, the oceans are the main source of the water vapor that makes atmospheric dynamics on our planet both interesting and exceedingly complicated. For these and other reasons, an explicit representation of the oceans should be the core of any self-respecting climate model.
However, the observational systems for the oceans are primitive in comparison with their atmospheric counterparts. Satellites that can keep track of what happens below the surface of the ocean have limited spatial and temporalresolution. Also, the scale of synoptic motions in the ocean is much smaller than that of cyclones in the atmosphere, requiring a spatial resolution in numerical models and in the observation network beyond the capabilities of present observational systems and supercomputers. We cannot observe, for example, the vertical and horizontal structure of temperature, salinity and motion of eddies in the Gulf Stream in real time with sufficient detail, and cannot model them at the detail that is needed because of computer limitations. How, for goodness’ sake, can we then reliably compute their contribution to multi-decadal changes in the meridional transport of heat? Are the crude parameterizations used in practice up to the task of skillfully predicting the physical processes in the ocean several tens of years ahead? I submit they are not.”
“You are not debating the point. The point is, does the quality of the weather forecasts we get indicate a good understanding of the how the weather works. It does, we get excellent quality compared to 30 years ago. If you want to meander off into some other debate, feel free.”
SJT, You are unbelievable. This is precisely the point.
The quality of the forcast is what I am talking about.
Just because it is getting better doesn’t make it correct.
And the quality is often lacking and while it may sound generally correct to the average picnic goer wondering what clothes to wear, it often lacks the accuracy for serious pursuits.
When you apply that lack of accuracy to long range climate forecasting you would have to be naive to accept their predictions.
Climate forcasting does not work the way you say it does. It ignores the initial conditions, because it cannot take a chaotic system and go from the initial state to the final state. They don’t pretend to, they don’t claim to. It’s like baking a cake, take the ingredients, mix it up, see what the result is. It’s much more complex than that in practice, as they track the changes in albedo and other factors. But you are comparing weather forecasting to modeling the climate. As for Pielke’s blog, if I was Gavin I’d tell him to take a hike, too. They relentlessly abuse the scientists, then abuse them for not wanting to be part of the process of abuse.
sjt
are you a pastry cook by any chance?
you seem to have this hang up about cakes.
““A climate model, however, has to deal with the entire climate system, which does include the world’s oceans. The oceans constitute a crucial slow component of the climate system. Crucial, because this is where most of the accessible heat in the system is stored. Meteorologists tend to forget that just a few meters of water contain as much heat as the entire atmosphere. Also, the oceans are the main source of the water vapor that makes atmospheric dynamics on our planet both interesting and exceedingly complicated. For these and other reasons, an explicit representation of the oceans should be the core of any self-respecting climate model.”
The current generation of climate models do incorporate the oceans and their effect on climate.
“the excuses of Hadley Center executive John Mitchell for refusing to provide his Review Comments on IPCC AR4 chapter 6 are among the most colorful: first, Mitchell said that he had destroyed all his correspondence with IPCC; then he said that they were his personal property. David Holland then submitted FOI requests for Mitchell’s expenses for trips to IPCC destinations and information on whether he had done so on vacation time, while also confronting Hadley Center with their representations to the public on how Hadley Center scientists were doing the British public proud through their participation as Hadley Center employees in IPCC. So Hadley Center foraged around for a new excuse – this time arguing that releasing Mitchell’s review comments would compromise British relations with an international organization (IPCC), IPCC in the meantime having informed Hadley Center that it did not consent to the review comments being made public – ignoring provisions in the IPCC by-laws that require them to make such comments public. In administrative law terms, there is unfortunately no recourse against IPCC – an interesting legal question that we’ve pondered from time to time (also see Global Administrative Law blog here.)
“We’ve also tried unsuccessfully to obtain Caspar Ammann’s secret review comments on chapter 6, which IPCC failed to include in their compilation of Review Comments and which Ammann and Fortress CRU have refused to make public.”
SJT,
Just a bit of comment on the quality of the IPCC “science” from Climate Audit.
McIntyre isnt’ interested in science, he’s only interested in character assasination. I’d tell him to go jump, too.
“McIntyre isnt’ interested in science, he’s only interested in character assasination. I’d tell him to go jump, too.”
These are details that are supposed to be supplied so others can replicate the science.
How can any IPCC report ever be a credible document with this attitude towards any enquiry?
“These are details that are supposed to be supplied so others can replicate the science.”
No, the scientific method to date has been on the basis that if you think they are right and they are wrong, you do your own work and prove yourself right. McIntyre has reduced the practice of science to a bitching match, and he seems to enjoy the snide remarks he regularly directs towards scientists, with juvenile name calling a regular occurance.
It’s bad enough when the IPCC produce this sort of “science”.
It’s worse when they prevent scrutiny.
It’s worse still when fools support their villainy.
It’s ten times worse when these same fools vilify someone who spends his life trying to correct the problem.
Postmodernist science anyone?