Another “observations are not models” story is emerging. For more on the status quo of thermohaline circulation, see this Wiki article – Anthony
Deep Ocean Conveyor Belt Reconsidered
Science Daily is reporting that just because they teach you something in graduate school doesn’t make it right. A 50 year old model of global thermohaline circulation that predicts a deep Atlantic counter current below the Gulf Stream is now formally called into question by an armada of subsurface RAFOS floats drifting 700 – 1500m deep. Nearly 80% of the RAFOS floats escaped the Deep Western Boundary Current (DWBC), drifting into the open ocean.
This confirms suspicions that have been around since the 1990’s, and likely plays havoc with global models of climate change. The findings by Drs. Amy Bower of Wood’s Hole and Susan Lozier of Duke University et al. are published in a forthcoming issue of Nature.
The implications would be for more cold, oxygenated water along the Mid-Atlantic Ridge, but I’m just making that last part up. Best to read for yourself. As I recall, the DWBC was notoriously slow. You have to wonder whether a big yellow float responds to these currents the same as suspended matter, like plankton and particulates. Either way, the research represents a major paradigm shift in ocean circulation theory.
Citation:
Bower, A., Lozier, M., Gary, S., & Böning, C. (2009). Interior pathways of the North Atlantic meridional overturning circulation Nature, 459 (7244), 243-247 DOI: 10.1038/nature07979
Image above from Wikimedia Commons.
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Pofarmer says:
No, that’s not what they’re saying. They’re saying that the cold water flowing south is more dispersed than thought before. They’re not saying anything at all about whether or not the ocean’s cooling.
I provided a link to commentary by one of the author’s above. Please read it rather than jump to the conclusion that it says something it doesn’t.
Steve Huntwork (12:33:31) :
When the density is affected by both temperature and salinity, then you get a thermohaline circulation, which may not always follow the intuition from heat convection alone.
Wikipedia on Thermohaline circulation.
The heat convection in (or out) of your home isn’t driven by differing density between salty air masses.
George E. Smith (13:40:37) :
Depending on how much you believe Newton’s laws, the rotation of the earth doesn’t “drive” anything at all in a large-scale geophysical flow. The Coriolis force is normal to the velocity (and hence does no work).
More heresy!
The science is getting unsettled.
Quick, somebody get a respirator handy – Al Gore’s gonna need it soon.
Anthony, please change the tag in the Wiki link to if possible. Thanks!
REPLY: Sorry, but your request is very unclear. The link works, what is wrong with it? – Anthony
Mr. FB, “Oh it’s a stool alright”
As in consolidated fecal matter.
Most excellent, sir, most excellent!
Dear Anthony,
The link is meant to be closed with an /a; instead I had put a /quote tag so that the entire rest of the post appears as part of the link.
REPLY: I’m sorry but, you are making subzero sense here. The link is properly closed, the html IS CORRECT. Whatever problem you are having is likely local to whatever setup your are using, and that is not some I can control. Besides why are your reading the HTML anyway? The link works, end of problem from my end. – Anthony
“Could someone explain to me the difference between thermohaline circulation and simple convection?”
It is sort of like what happens with inversion layers in the atmosphere. Air warms, becomes less dense and rises but if it hits a layer of air less dense than it is, it can’t rise beyond it.
Temperature can impact density and there can be layers of water that have different temperature and salinity. So while a layer might be warmer and normally want to rise, it is also saltier and therefore more dense. So as you drop in depth, it is possible you might come to a warmer layer of deeper water but it is saltier than the water above. Or as you rise, you might experience a colder layer that is fresher and can’t sink through the saltier layer below it.
So thermohaline would imply changes in layers of water where both the temperature (thermo) and salt content (hal) play a role in stratification.
George E. Smith (13:40:37) :
Well I’m not a fan of the “thermohaline” circulation; despite its bloated name.
Oh I believe the oceans circulate all right; and I also believe that salinity can determine when and if and where water will decide to sink. But I also believe that the energy driving this is essentially the rotation of the earth.
Would cycles or perturbations in the earth’s rotation, reflected in LOD (length of day), then likely be reflected in ocean circulation? Makes sense to me.
Thermohalines be damned. George Moonbat has the REAL news from the World of the Grauniad.
http://www.guardian.co.uk/environment/georgemonbiot/2009/may/07/monbiot-climate-change-evacuation
They cut down the mangrove trees and now wonder why the sea is eroding their island. Can anyone help?
One thing I never quite understood about those thermohaline models… but never really asked about.
By what mechanism does deep “more saline” water become less saline and thus rise to the surface in the North Pacific, and yet become more saline and thus heavier to sink in the North Atlantic?
Oops – did someone’s karma run over someone’s dogma?
If the paper is in Nature (Green Peace East) it is biased as hell when it comes to AGW. You will never see a paper that shows the full picture with even a hint that there might be a problem to the AGW story. I have dropped my membership to Nature, guess I will miss this one.
“”” Basil (14:56:41) :
George E. Smith (13:40:37) :
Well I’m not a fan of the “thermohaline” circulation; despite its bloated name.
Oh I believe the oceans circulate all right; and I also believe that salinity can determine when and if and where water will decide to sink. But I also believe that the energy driving this is essentially the rotation of the earth.
Would cycles or perturbations in the earth’s rotation, reflected in LOD (length of day), then likely be reflected in ocean circulation? Makes sense to me. “””
Basil, while i believe the earth rotation provides the drive to keep this water flowing; be it coriolis effect or what have you; I think the actual nature of the circulations is way to complex to discern any behavioral linkage to changes in LOD. That would be some kind of spectacular if such an influence could be detected.
I’m not saying it doesn’t happen; but I think it is so far down in the noise mud; you’d never prove the linkage.
I remember when I was learning about the cosmos in college. We were taught that the rings on Saturn were of a specific composition and they even had names… zooom Saturn gets a drive by…. gee its just random rubble. My point is that sometime science gets ahead of itself. Theorys are not facts, they are educated guesses. At any time a theory can be proven false. That is supposed to be the beauty of science, so when someone says the science is settled you can count on it being disproved, improved or totally tossed. True science is observation. I hate that every scientist has a conclusion to their research now. What happened to observing and pushing the envelope of what we know now rather then figuring out where it all should end?
“”” oms (14:21:11) :
Steve Huntwork (12:33:31) :
Could someone explain to me the difference between thermohaline circulation and simple convection?
When the density is affected by both temperature and salinity, then you get a thermohaline circulation, which may not always follow the intuition from heat convection alone.
Wikipedia on Thermohaline circulation.
To my knowledge, nobody has suggested that I could insulate my home more efficiently, by reducing the salt content of the air.
The heat convection in (or out) of your home isn’t driven by differing density between salty air masses.
George E. Smith (13:40:37) :
Oh I believe the oceans circulate all right; and I also believe that salinity can determine when and if and where water will decide to sink. But I also believe that the energy driving this is essentially the rotation of the earth.
Depending on how much you believe Newton’s laws, the rotation of the earth doesn’t “drive” anything at all in a large-scale geophysical flow. The Coriolis force is normal to the velocity (and hence does no work). “””
So taking your word for it, that the rotation of the earth is not driving anything; I take it that the gulf stream, and the Japan current could one day decide to flow the opposite direction. By inference I might also expect the trade winds and other atmospheric flows to change direction since they are unrelated to the earth’s rotation.
Well that will be nice to one day get yeloowfin tuna running along our California coast, instead of salmon.
Jeremy (15:14:53) :
Nothing wrong with asking. Evaporation and other cooling as the Gulf Stream moves northward, plus ice formation, make cold, saline water in the North Atlantic. That water sinks. The water in the Pacific is by contrast much less saline, taking on more rainful and facing less intensive evaporation.
By what mechanism does the salty water rise back up? That is an open question in oceanography. It seems safe to say it has to happen somehow.
-oms
P.S. Apologies to Anthony about the earlier requests; apparently my browser wasn’t refreshing properly. I had no idea it would cause such a reaction, as no badgering was intended.
“By what mechanism does deep “more saline” water become less saline and thus rise to the surface in the North Pacific, and yet become more saline and thus heavier to sink in the North Atlantic?”
Water coming out of the Gulf of Mexico is VERY salty compared to the rest of the Atlantic but it rides on top because it is so much warmer. Once it gets up North, it finally cools to a point where it is finally denser (but still a bit warmer) than the water below it and it plunges under. The North Atlantic surface water is generally fresher than the rest of the ocean because it contains a lot of melt water and runoff from N. America / Eurasia.
Not up on what is going on with the Pacific side. The two oceans wouldn’t be expected to behave exactly the same because the surrounding geography is different.
Re: geo (11:45:51)
Well-said.
– – –
Re: Bill Illis (11:05:40)
I think I see your (perhaps subtle) point: too many “should”s.
– – –
Re: crosspatch (11:30:54)
Maybe you meant for that to be sarcastic & humorous; I want to convey that that is actually how it works (in my neck-of-the-woods, at least) — far from humorous, it is absolutely tragic. Thank you for drawing attention to this real plight.
– – –
dhogaza (11:47:38) “The difficulty isn’t to climate science, per se, but rather a whole lot more data gathering in the deep sea is going to be necessary when looking for climate signals. In other words a lot more $$$ and most likely time to both gather and analyze such data.”
Don’t forget the other problems:
1) No time-travel (to go back in time to get the samples needed).
2) No replication (i.e. only 1 Earth).
Can this even be settled..? Not within the lifetime of anyone living, I would venture (…but [clearly] many will continue in misguided-attempts to convince the innocent [assumed-naive] public otherwise).
So as I learn new things in my quest for understanding:
In 2009 “We know that a good fraction of the human caused carbon dioxide released since the Industrial revolution is now in the deep North Atlantic”
I am immediately perplexed by this from 2006:
“Dr. Peter Flynn, the Poole Chair in Management for Engineers in the U of A Department of Mechanical Engineering, has studied whether down-welling ocean currents can carry more dissolved carbon into the deep ocean. He learned they can’t, … http://www.sciencedaily.com/releases/2006/02/060206230019.htm
Clearly someone isn’t part of the “we know” or am I just “cherry picking”.
But at least there is hope for real practical science in these dark times:
“To learn more about how the cold deep waters spread, we will need to make more measurements …” (please send more money)
but you just can’t go past a good ole model:
“… also used a modeling program to simulate the launch and dispersal of more than 7,000 virtual “efloats” from the same starting point. ….. “The spread of the model and the RAFOS float trajectories after two years is very similar,” they reported.”
You would bloody well hope so! Isn’t that what models are meant to do? (Slap me – I forgot these are climate models)
As an aside, if floats escape, do e-floats e-escape ?
But if I understand this, 8% went down the conveyor, 75% followed some other “pathways” and no mention of the other 17%.
But oh how times have changed when you can actually challenge settled science:
“studies in the 1990s using submersible floats that followed underwater currents “showed little evidence of southbound export of Labrador sea water within the Deep Western Boundary Current (DWBC),” …. Scientists challenged those earlier studies, ….. data could have been “biased… etc etc
and if I understand it, come to exactly the same conclusion ????
I too am a bit unsettled …
Quote of the week:
Ira (10:24:11) :
Things are not what they used to be – and THEY NEVER WERE.
I look at the Earth with the oceans and air as a single entity obstructing the flow of energy from the sun.
Short wave solar energy hits the Earth, some gets absorbed by Earth, oceans and air and is then radiated out as long wave energy.
In the course of that process heat energy is released around the planet and radiated out with the rest of the electromagnetic energy received from the sun. The shift from short wave to long wave is just like the reduction in voltage as a current passes through a resistor thereby generating heat.
That entire process, taken as a whole, sets the so called equilibrium temperature of the planet.
The air is a contributor to the equilibrium temperature albeit miniscule as against the effect of the oceans.
CO2 is a contributor to the equilibrium temperature albeit miniscule as against the effect of the air.
Human CO2 is a contributor to the portion of the equilibrium temperature provided by CO2 albeit miniscule as against the effect of the rest of the CO2.
The climate scientist Tyndall and his successors upon whom so many now rely was concerned only about human produced CO2 which is but a tiny bit of the natural CO2 which is but a tiny bit of the air which is but a tiny bit of the entire effect. He ignored the oceans completely as do all climate change alarmists to this day.
He is 100% right about that tiny, tiny, tiny bit but 100% wrong about the significance of that tiny, tiny, tiny bit for the equilibrium temperature of the planet.
That is why all attempts to date at modelling the climate have failed and they will continue to fail for the foreseeable future until we know a great deal more about the oceans.
That’s the clearest and simplest way I can put it.
“By what mechanism does deep “more saline” water become less saline and thus rise to the surface in the North Pacific, and yet become more saline and thus heavier to sink in the North Atlantic?”
…become less saline…
There are in some places, apparently, fresh water springs that still emit beneath the oceans. Apparently these were in existence during the last glacial period and enabled man to survive (in terms of available fresh water) as the initial exodus of Homo sapiens from East Africa to the Asian continent via the Arabian Peninsula took place despite local desert conditions. (Disclaimer: Possibly total misrepresentation as it came from a recent BBC documentary on early human migrations.)
…become more saline…
When brine freezes each year,at the underside of the sea ice near the poles, salt in the brine becomes more concentrated in the water, and the ice formed ice contains a greater proportion of the fresh water.
Despite being warmer than less briny surrounding water, concentrated brine may have a higher density, and thus sink. “solar ponds” work on this principle- with hot concentrated brine at the bottom, and cooler, less salty water at the top.
Craigo, what’s being discussed there is whether or not enhancing downwelling is a practical geoengineering approach to pulling more CO2 into the ocean (thereby mitigating against increasing CO2 concentrations).
I think the major problem here has nothing to do with science or engineering, but rather a really badly written blurb in Science Daily.
Jeremy asked the correct question, and why I was teasing about insulating my home during the Minnesota winters.
I have a cartoon picture in my mind:
Warn water from the equator rushing to the poles along the gulf stream and gushing into space like a fountain, because there is no salt to make it sink!
The replies have been rather funny to read….
Thanks Jeremy.
Jeremy (15:14:53) :
One thing I never quite understood about those thermohaline models… but never really asked about.
By what mechanism does deep “more saline” water become less saline and thus rise to the surface in the North Pacific, and yet become more saline and thus heavier to sink in the North Atlantic?
Chris Knight:
As a scuba diver and cave explorer, I know all about how fresh water will float over salt water in a calm cave environment. The transition between the layers in a cave can be rather amazing. However, a cave is a very special environment and rather unique.
This model fails when you have any mixing of the water layers and they merge into each other.
That is what currents, convection and other motions will do to water layers. They all get mixed up!