Breaking deep-sea waves reveal a potential mechanism for global ocean mixing

From the “Trenberth’s hidden heat” department and the University of Washington comes this story about waves nobody ever sees in the sea that may mix water and transport heat.
screenshot_wave_graph[1]

The deep-sea waves are 800 feet tall, as high as a skyscraper. Image: Tom Peacock, MIT | Wide Eye Productions

Waves breaking over sandy beaches are captured in countless tourist photos. But enormous waves breaking deep in the ocean are seldom seen, although they play a crucial role in long-term climate cycles.

A University of Washington study for the first time recorded such a wave breaking in a key bottleneck for circulation in the world’s largest ocean. The study was published online this month in the journal Geophysical Research Letters.

The deep ocean is thought of as dark, cold and still. While this is mostly true, huge waves form between layers of water of different density. These skyscraper-tall waves transport heat, energy, carbon and nutrients around the globe. Where and how they break is important for the planet’s climate.

“Climate models are really sensitive not only to how much turbulence there is in the deep ocean, but to where it is,” said lead author Matthew Alford, an oceanographer in the UW Applied Physics Laboratory. He led the expedition to the Samoan Passage, a narrow channel in the South Pacific Ocean that funnels water flowing from Antarctica.

“The primary importance of understanding deep-ocean turbulence is to get the climate models right on long timescales,” Alford said.

Dense water in Antarctica sinks to the deep Pacific, where it eventually surges through a 25-mile gap in the submarine landscape northeast of Samoa.

“Basically the entire South Pacific flow is blocked by this huge submarine ridge,” Alford said. “The amount of water that’s trying to get northward through this gap is just tremendous – 6 million cubic meters of water per second, or about 35 Amazon Rivers.”

In the 1990s, a major expedition measured these currents through the Samoan Passage. The scientists inferred that a lot of mixing must also happen there, but couldn’t measure it.

In the summer of 2012 the UW team embarked on a seven-week cruise to track the 800-foot-high waves that form atop the flow, 3 miles below the ocean’s surface. Their measurements show these giant waves do break, producing mixing 1,000 to 10,000 times that of the surrounding slow-moving water.

“Oceanographers used to talk about the so-called ‘dark mixing’ problem, where they knew that there should be a certain amount of turbulence in the deep ocean, and yet every time they made a measurement they observed a tenth of that,” Alford said. “We found there’s loads and loads of turbulence in the Samoan Passage, and detailed measurements show it’s due to breaking waves.”

It turns out layers of water flowing over two consecutive ridges form a lee wave, like those in air that passes over mountains. These waves become unstable and turbulent, and break. Thus the deepest water, the densest in the world, mixes with upper layers and disappears.

This mixing helps explain why dense, cold water doesn’t permanently pool at the bottom of the ocean and instead rises as part of a global conveyor-belt circulation pattern.

The Samoan Passage is important because it mixes so much water, but similar processes happen in other places, Alford said. Better knowledge of deep-ocean mixing could help simulate global currents and place instruments to track any changes.

On a lighter note: Could an intrepid surfer ride these killer deep-sea waves?

“It would be really boring,” admitted Alford, who is a surfer. “The waves can take an hour to break, and I think most surfers are not going to wait that long for one wave.”

In fact, even making the measurements was painstaking work. Instruments took 1.5 hours to lower to the seafloor, and the ship traveled at only a half knot, slower than a person walking, during the 30-hour casts. New technology let the scientists measure turbulence directly and make measurements from instruments lowered more than 3 miles off the side of the ship.

The researchers left instruments recording long-term measurements. The team will do another 40-day cruise in January to collect those instruments and map currents flowing through various gaps in the intricate channel.

Co-authors of the paper are James Girton, Gunnar Voet and John Mickett at the UW Applied Physics Lab; Glenn Carter at the University of Hawaii; and Jody Klymak at the University of Victoria. The research was funded by the National Science Foundation.

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I understand. Global warming happens nowhere in particular and to nobody specifically, via invisible waves and a mechanism mostly impossible to follow that acts in regions of the globe with minimal or zero link to anything else.
Just like the fairies.

markx

Dang it! After all words telling us how well they understood all this, they come along and tell us about the previously unmentioned “so-called ‘dark mixing’ problem”, and then assure us they have now sorted it out.
Why don’t I feel re-assured?

Jeef

This is so underwhelming its untrue. In one very small part of one very large ocean there’s measurable turbulence?
Stick to that theory and it’s science. Anything further is pure conjecture.

Greg Goodman

I did some back of envelop figures some time back on the time scale of deep ocean tides.
This seems to be a similar thing.
There is a density difference between the surface mixed layer and the deeper, cooler and more saline waters. That is subject to the same lunar / solar gravity differential that is the main cause for surface tidal patterns, except that the density difference is about 1000 less than the air/water interface. Thus major tides will 1000 times slower.
The puts variations of the order of years. Is this not a likely explanation for the origin of El Nino cycles?

Greg Goodman

To above objections, this paper just deals with one local site but it does establish that this deep interface has waves analogous to those of the ocean surface. If there are wave there will also be tides. If the waves are 300 ft now high are the tides.
Deep, slow basin wide tidal movements right across that Pacific (and other major basins) could easily explain El Nino events and seems more convincing that all the usual talk about “sloshing” back and forth due to winds.
There is a NOAA (or NASA) animation of the thermocline in the Pacific and it does just this.

Greg Goodman

The mention of 12h tides above is just to get the timescale of how such an interface would respond. It will be far too slow to be affected by the classic 24h variations in tidal forces. However, longer cycles like the 4.43y passage of the lunar perigree precession across the equator may be able to create tidal patterns in this slow moving interface.
El Nino is decribed as 3 to 5 year pseudo cycles. Modulate 4.43 years with something like 28 years and you get just that.
And you can find exactly that happening in trade wind and other climate data.
http://climategrog.wordpress.com/?attachment_id=283

JDN

What are the chances that GRL doesn’t know how to define turbulent mixing from any other type of mixing? Why can’t it be stream instability?
In addition, for there to be an instability, there must be an energetic advantage to the unstable flow. What is it in this case? Also, if you run a large current through a small-ish channel, you are going to do mechanical work, at least on the boundaries. Is there any contribution from mechanical work here?

Greg Goodman

This is surface long period wave (simulated from 1988) in Pacific.
http://www.esrl.noaa.gov/psd/people/joseph.barsugli/anim.html
“The relatively small motions in sea level shown here (10 – 20 centimeters) are indicative of much larger motions in the opposite direction in the depth of the thermocline below the surface.”
Thermocline tide.
http://www.esrl.noaa.gov/psd/people/joseph.barsugli/enso_anim_jjb2.html
http://www.esrl.noaa.gov/psd/people/joseph.barsugli/mov_tao.gif

I’ve always wondered about the possibility of such deep-sea waves, for water seemingly would be injected into the thermohaline circulation in an irregular manner, almost like a heart-beat, and that might create waves.
During the summer phase, as ice melts, the melt-water is relatively fresh. It creates a “lens” of more brackish sea-water atop the Arctic Sea. (Some Alarmists speak of a “lens of fresh water,” but the water is still too salty to drink, and even at its least salty it still needs to get down to around -1.7 c to freeze.) This water seemingly does not go down deep and add to thermohaline circulation.
During the refreeze phase, as ice forms, salt is extracted. This process is interesting in and of itself, with little drops of brine melting their way down through the ice. Although “baby ice” retains a little more salt than “multi-year ice,” most salt is removed right at the start, and even “baby ice” is relatively fresh. The brine that is removed can be well below the freezing point of salt water, and is very dense. This water seemingly would sink down and add to the thermohaline circulation.
These injections ought occur in an alternating manner, matching the refreeze first in the Arctic, and then in the Antarctic. The question then becomes, would they create waves, or differences in pressure (even though water is non-compressible?) And, if such waves are created, what would happen when such a wave ran up against a continental shelf, such as the coast of Peru where we all watch for signs of cold up-welling that adds to a La Nina? (I’m not saying it would be a major effect, as great as trade winds, but….could it mess up delicate calculations, and trigger changes in the manner a pebble triggers an avalanche?)
I’m glad to see a little funding is doing some actual exploration of the mysterious deeps. Hansen wasted too much on mere models, and even more messing up past records with “adjustments.”
I ventured some thoughts about these ideas two Septembers ago, hoping to stimulate WUWT discussion. If you can overlook a dunderheaded mistake I made, (using the word “pneumatic” when I meant “hydraulic,”) it is a start to a discussion I think it would be interesting to continue.
http://wattsupwiththat.com/2011/09/18/a-laymans-paper-pneumatic-effects-on-thermohaline-flow/

WJohn

This raises the exciting prospect of submarine (adjective) submarine (noun) surfing.
If anybody knows anything about this it will be the world submarine (noun) operators, and they will tell you nothing.

H.R.

“…. or about 35 Amazon Rivers.”
How much is that in SI Units i.e. Olympic swimming pools?
What percent of the world’s ocean mixing does this area represent? They have found one spot where there are actual measurements of the mixing (yay! Observations!). How many more places do they need to find to add up to a global effect on climate?

Konrad

No, there is no “missing heat” hiding in the oceans, leaping out to cause “extreme weather” then running away and hiding again. Neither LWIR or heated air can significantly effect the cooling rate of liquid water let alone heat it. The gas/liquid interface at the ocean surface is a special condition. Calculating the effect of incident LWIR using the emissivity figures for liquid water is one of the critical mistakes in climate pseudo science. This can be demonstrated by the following simple experiment –
Experiment 1. Effect of incident LWIR on liquid water that is free to evaporatively cool.
Incident LWIR can slow the cooling rate of materials. Climate scientists claim that DWLWIR has the same effect over oceans as it does over land, and this is shown in many Trenberthian energy budget cartoons. Does the ocean respond to DWLWIR the same way as land?
– Build two water proof EPS foam cubes 150mm on a side and open at the top.
– Position a 100mm square aluminium water block as LWIR source 25mm above each cube.
– Position two small computer fans to blow a very light breeze between the foam cube and the water blocks.
– Insert a probe thermometer with 0.1C resolution through the side of each cube 25mm below the top.
– Continuously run 80C water through one water block and 1C water through the other.
– Fill both EPS foam cubes to the top with 40C water an allow to cool for 30 min while recording temperatures.
– Repeat the experiment with a thin LDPE film on the surface of the water in each cube to prevent evaporative cooling. Now incident LWIR can slow the cooling of the water sample under the 80C aluminium water block.
Here is an early variant of this experiment in which IR from cooling water samples was reflected back to the water surface – http://i47.tinypic.com/694203.jpg

Bloke down the pub

This type of wave has been suggested as a plausible explanation for many of the Loch Ness monster sightings. Loch Ness is long, and very deep, and waves traveling along the thermocline can travel up and down it’s length for a long time after the initial event that triggered them.

RE: Greg Goodman says:
September 11, 2013 at 2:25 am
Wow! What a terrific animation! True, it is a “model,” but it shows some thinking is going on. Thanks for sharing it.

johnmarshall

yeah, right so these waves mix the waters, including the missing heat and the ARGO buoys cannot detect it????
I do not doubt the undersea turbulence, but the rest?

Jimbo

The point about deep sea diving ‘missing heat’ is simple. What goes in must come out and has always been with us. Now let’s look back at the recent warming.

Alpo Martikainen

It must bumpy drive for submarine ,,,,

izen

@- Konrad
No, there is no “missing heat” hiding in the oceans, leaping out to cause “extreme weather” then running away and hiding again.
If there is no additional heat in the oceans that could have caused thermal expansion then ALL the sea level rise over the last 15 years would have to be explained by the melting of land based ice and the extraction of water from deep aquifers being fed back to the oceans.
Direct observations do not support enough melting or ocean drainage of aquifers to explain the observed rise in sea level. Thermal expansion, indicating deep heating of the oceans is an unavoidable deduction.

Greg Goodman

Caleb would the linkage between AO index and tropical atm CO2 help your WHADUP plan;
http://climategrog.wordpress.com/?attachment_id=259

MojoMojo

There is heat at the bottom of the ocean.From underwater volcanoes.

tty

WJohn says:
September 11, 2013 at 2:29 am
This raises the exciting prospect of submarine (adjective) submarine (noun) surfing.
If anybody knows anything about this it will be the world submarine (noun) operators, and they will tell you nothing.

Been there, done that. This technique was used by german U-boats transiting Gibraltar Sound in WW 2.

Greg Goodman

tty “Been there, done that. This technique was used by german U-boats transiting Gibraltar Sound in WW 2.”
Wouldn’t that be gliding out on the tide rather than surfing the thermocline?

MattN

This is all very convenient, isn’t it?

izen:
In your post at September 11, 2013 at 3:19 am
http://wattsupwiththat.com/2013/09/11/breaking-deep-sea-waves-reveal-a-potential-mechanism-for-global-ocean-mixing/#comment-1414056
you say

Direct observations do not support enough melting or ocean drainage of aquifers to explain the observed rise in sea level. Thermal expansion, indicating deep heating of the oceans is an unavoidable deduction.

NO! That is a falsehood.
The unavoidable reality is that there are no measurements with sufficient accuracy to support your assertion.
Richard

@Anthony
>The study was published online this month
>in the journal Geophysical Research Letters.
http://onlinelibrary.wiley.com/doi/10.1002/grl.50684/abstract
Yes, “online” but seems to be blocked by a paywall. Am I missing a public, free access link?
My question is: Did the UW team actually observe (and record) these 800 foot waves, or did they merely infer their existence by sampling the turbulent mixing products?
Don’t recall ever seeing anything approaching ‘monster waves’ like this in NOAA’s Pacific wave and wind forecasts, which I assume are based partly on extrapolations of observations:
http://www.opc.ncep.noaa.gov/shtml/P_48hrwind_wave.gif
So color me slightly confused/skeptical on what this report is really telling us.
😐

gopal panicker

of course the Oceans are the key to climate…monsoon…enso…etc… are driven by ocean currents…if cold salty water sinks…it must displace something…circulation…the submarine guys…who one would think are the best informed about this stuff…dont go very deep…maybe 300 meters max…average depth of the oceans is about 4500 meters

Geoff Sherrington

izen says: September 11, 2013 at 3:19 am Re: speculation on deep ocean heat.
1. Measure it.
2. Report back when you have finished.
3. Don’t speculate.

Gary Pearse

Such a mechanism would be easily experimented with in a flume. Why are climate scientists so afraid of experimentation – we have to stop the silly baloney even supported by skeptics that the climate is so chaotic and can’t be experimented with. Although chaotic systems are apparently real, I’m afraid the relief this too broad an idea gives to the unimaginative is an impediment to science. I’m sure most of the systems branded chaotic are of the throw-your-arms-up variety and the chaos would largely disappear with more ingenuity (and the knowledge that can be gleaned):
https://www.google.ca/search?q=laboratory+flume&client=firefox-a&hs=e4j&rls=org.mozilla:en-US:official&tbm=isch&tbo=u&source=univ&sa=X&ei=-FIwUrroEOqY2gWygYHAAg&ved=0CCwQsAQ&biw=853&bih=435
The flume: you could dye the high-salt water a different colour and you won’t have such arduous journeys as a 40 day trip to Samoa! You could even use a range of densities for the heavier fluid to see variations in the efficiency of the effect. I’m a little suspicious of the waves breaking dramatically in a slow moving pulse. They would most likely maintain a smooth profile. How much turbulence is there in a bulging pipe with slow movement of the fluid? Also, they measure this at a three mile depth. How thick is this layer? If you have to voyage all the way to Samoa to do this research and you need the precise conditions of two parallel ridges a certain distance apart for this to happen with 6 km^3 s^-1 of water, How representative of this condition is it for the other 99.99% of the cold salty water flow from both poles? Do the flume tests and get back to me on this.

izen

@- richardscourtney Re:- thermal expansion of the oceans.
“The unavoidable reality is that there are no measurements with sufficient accuracy to support your untrue assertion.”
The unavoidable reality is that the field of geology considers that it CAN measure the thermal expansion of the oceans quite adequately. While there are various aspects of science that are difficult or open to interpretation, the measurement of sea level rise is an objective physical measurement that can be determined by multiple methods, all of which give consistent results.
Claiming that geologists and oceanographers {not climate scientists} are incapable of making the measurements they report and must therefore be lying when they report the accelerating rise in sea levels would seem to put you in the position of rejecting another whole branch of the physical sciences.
Or perhaps you are implying that the scientists who report the rising sea level are acting in a fraudulent manner and are inventing the measurements to be consistent with the climate field?
http://sealevel.colorado.edu/

Janice Moore says:
September 11, 2013 at 2:39 am

Thanks for that remembrance. Still hard to look at those images, but great song by Alan Jackson.
/Mr Lynn

joshv

I don’t really understand why water needs to move to transport heat. Water is quite conductive to heat. Certainly mixing will accelerate the process, but the notion that heat could be “sequestered” under the ocean seems patently ludicrous.

Ian Wilson

The eighth figure in this post:
http://astroclimateconnection.blogspot.com.au/2011/11/el-ninos-and-extreme-proxigean-spring.html
gives some idea of the extent of world-wide cool deep water mixing that is caused by lunar tides.
Studies of this tidal dissipation have been made in the Hawaiian Islands showing that ocean-bottom lunar tidal dissipation plays an important role in the up welling of deep ocean waters.

Gary

Three miles down, what’s the temperature difference between two water parcels only 800 feet apart vertically? The miniscule difference is going to matter to the models? Grasping at straws…

Geoff Sherrington

In our understanding of oceans, we are still at a level of gaining confidence in data through data collection and analysis.
For analysis, here is a recent paper:
http://pluto.mscc.huji.ac.il/~msdfels/wpapers/Tide%20gauge%20location.pdf
………………………….
From abstract,
Mean Sea Level (PSMSL) during 1807 – 2010 without recourse to data reconstruction. Although mean sea levels are rising by 1mm/year, sea level rise is local rather than global, and is concentrated in the Baltic and Adriatic seas, South East Asia and the Atlantic coast of the United States. In these locations, covering 35 percent of tide gauges, sea levels rose on average by 3.8mm/year. Sea levels were stable in locations covered by 61 percent of tide gauges, and sea levels fell in locations covered by 4 percent of tide gauges. In these locations sea levels fell on average by almost 6mm/year.

@joshv
>Water is quite conductive to heat.
Compared to what? Water is less conductive thermally than concrete or glass …
Glass,ordinary 0.8
Concrete 0.8
Water at 20° C 0.6
… and way less conductive than diamonds, the most thermally conductive substance known (thus explaining the nickname ‘ice’ for diamonds)
Diamond 1000
(units: watts per meter-Kelvin)
http://hyperphysics.phy-astr.gsu.edu/hbase/tables/thrcn.html

Latitude

A perfect example of over thinking something you don’t know…

tim in vermont

I live on Lake Champlain and it has been known for years that there are waves in the thermocline that move the thermocline up and down by something like 30 ft over a matter of hours. Because of the long narrow nature of the lake, they bounce back and forth. Sometimes they “break” against one end of the lake or another exposing the cooler water to the surface.
Here is a paper on it.
http://onlinelibrary.wiley.com/doi/10.1029/98JC01450/abstract;jsessionid=21D2385959CA6288F0AF24C789351E26.d02t04?deniedAccessCustomisedMessage=&userIsAuthenticated=false

buck smith

The heat capacity of the oceans is 1000 times the heat capacity of the atmosphere. So if we would have warmed an additional 2C from GHG warming, but instead that heat went missing into the Oceans, then the Oceans are now 0.002C warmer. And guess what, the most warming that missing hear can now give back to the atmosphere is 0.002C So if the models

buck smith

Sorry My comment was just this:
The heat capacity of the oceans is 1000 times the heat capacity of the atmosphere. So if we would have warmed an additional 2C from GHG warming, but instead that heat went missing into the Oceans, then the Oceans are now 0.002C warmer. And guess what, the most warming that missing hear can now give back to the atmosphere is 0.002C

Bill Illis

I guess what is interesting about this is that by measuring this choke-point for deep ocean water flow, we can now say that the Antarctic Deep Ocean Water is actually flowing into the north Pacific.
Many of the Thermohaline Ocean Circulation models showed this to be occurring but there was no real evidence for it and no real place where they could say it eventually upwells/surfaces, hundreds of years later, after warming up from 0.0C to 12.0C for example. I always thought it was just theoretical because there was no real evidence for it while there was evidence for other Antarctic Deep Water upwelling areas.
Image of the region.
http://s21.postimg.org/bpif57con/Samoan_Passage.jpg
Google Maps link – just east of Tokelau. Choke point for deep ocean flow for thousands of kms to the west side of Australia.
https://www.google.ca/maps?ll=-15.834536,-177.84668&spn=31.668157,67.631836&t=h&dg=opt&z=5

Jeff Norman

There is a pattern appearing out of the noise again/still.
Official climate science comes up with a new hypothesis to explain some failure in the overall global warming hypothesis, in this case saying the missing heat is in the deep oceans.
Skeptics point out a weakness in the proposed hypothesis, in this case saying there is no mechanism for getting surface heat into the deep oceans.
Climate science apparatchik then pile in saving there is no weakness, in this case saying wave action, downwelling ocean currents take the heat down.
The discussion between skeptics and apparatchik devolves to name calling.
Official climate science comes up with a new hypothesis to explain some failure in the overall global warming hypothesis, in this case saying deep ocean mixing is carrying the heat into the deep oceans.
Etc.
This cycle continues in the discussions around UHI and the missing mid-troposphere heat.
At no point will anyone say, “Hey the skeptics were right!”

Berthold Klein

The most important thing this report presents is” That the science is not settled”!
There is no “credible experiment that proves that the hypothesis of the greenhouse gas effect exists”
There is an experiment that proves that the Greenhouse gas effect does not exist. This experiment which has been technologically reviewed by Ph.D physicists . Ph.D. Chemical engineers and others Ph. D’s in other fields The experiment is found on the web-site http:// http://www.slayingtheskydragon.com click on the blog tab then on page 3 of 12. . It is titled “The Experiment that failed which can save the world trillions-Proving the greenhouse gas effect does not exist”
The Greenhouse Effect Explored
Written by Carl Brehmer | 26 May 2012
Is “Water Vapor Feedback” Positive or Negative?
Exploiting the medium of Youtube Carl Brehmer is drawing wider attention to a fascinating experiment he performed to
test the climatic impacts of water in our atmosphere.
Carl explains, “An essential element of the “greenhouse effect” hypothesis is the positive “water vapor feedback” hypothesis. That is, if something causes an increase in the temperature this will cause an increase in the evaporation of water into water vapor.”
Another important website is www. The Great Climate Clash.com -G3 The Greenhouse gas effect does not exist.
Dr. Vincent Gray on historical carbon dioxide levels
Posted on June 4, 2013 by Anthony Watts
NZCLIMATE TRUTH NEWSLETTER NO 312 JUNE 4th 2013
CARBON DIOXIDE
There are two gases in the earth’s atmosphere without which living organisms could not exist.
Oxygen is the most abundant, 21% by volume, but without carbon dioxide, which is currently only about 0.04 percent (400ppm) by volume, both the oxygen itself, and most living organisms on earth could not exist at all.
This happened when the more complex of the two living cells (called “eukaryote”) evolved a process called a “chloroplast” some 3 billion years ago, which utilized a chemical called chlorophyll to capture energy from the sun and convert carbon dioxide and nitrogen into a range of chemical compounds and structural polymers by photosynthesis. These substances provide all the food required by the organisms not endowed with a chloroplast organelle in their cells.
This process also produced all of the oxygen in the atmosphere
The relative proportions of carbon dioxide and oxygen have varied very widely over the geological ages.
Oxygen_earths_atmosphere_historical
CO2_temperature_historical
It will be seen that there is no correlation whatsoever between carbon dioxide concentration and the temperature at the earth’s surface.
During the latter part of the Carboniferous, the Permian and the first half of the Triassic period, 250-320 million years ago, carbon dioxide concentration was half what it is today but the temperature was 10ºC higher than today . Oxygen in the atmosphere fluctuated from 15 to 35% during this period
From the Cretaceous to the Eocene 35 to 100 million years ago, a high temperature went with declining carbon dioxide.
The theory that carbon dioxide concentration is related to the temperature of the earth’s surface is therefore wrong.
Keep up the work to study what is really causing changes in the weather. Climate is the average pattern of thousands of weather events in one location.

Robertv

What transit time between sinking and surge are we talking about.? 1 year 10 years 100 years ?
Radioactive carbon-isotope dating of the deep waters indicates that from the time of sinking into the deep until its return to the surface, a period of several hundred or even up to 1000 years will pass.
http://worldoceanreview.com/en/wor-1/climate-system/great-ocean-currents/
So that should mean that the energy pumped into the systeem many centuries ago (MWP) influences today’s climate.

Pamela Gray

Yes. This supports data that shows the age of stable deep water to be less than modeled age. The overturning system in models is very simplified with primary action at the poles. Thus models predict that it takes a long time for deep water to rise to the surface. However, when the actual age of deep water is measured, its age is quite a bit younger than the models predict, indicating that mixing is happening more frequently than was thought.
So take a look at the globe with the water removed. draw in what we know about the general placement and direction of the deep water currents. Notice all the mountain ridges? If these ridges stand in the way of a deep water current, mixing of old deep water could be happening there.

Rick Bradford

Desperate to plug yet another hole in the AGW dyke, the Warmists make a wild guess and call it a ‘plausible mechanism’.

Tom J

800 foot tall subsurface waves that were not previously known to exist because there’s no physical representation whatsoever on the surface? Huh?

mkelly

The researchers left instruments recording long-term measurements. The team will do another 40-day cruise in January to collect those instruments and map currents flowing through various gaps in the intricate channel.
So they will be going from the cold, wet, cloudy state of Washington in January to the warm climes of 8 south latitude. Not a bad gig if you can get it.

Phil.

tty says:
September 11, 2013 at 3:50 am
WJohn says:
September 11, 2013 at 2:29 am
This raises the exciting prospect of submarine (adjective) submarine (noun) surfing.
If anybody knows anything about this it will be the world submarine (noun) operators, and they will tell you nothing.
Been there, done that. This technique was used by german U-boats transiting Gibraltar Sound in WW 2.

You beat me to it!
Here’s a good article on the u-boats and the Med., there’s an interesting piece near the end about a soviet submarine that was slipping in under a tanker when it got lifted up by one of those waves and hit the tanker. Had to surface, very embarrassing!
http://formontana.net/uboats.html

phlogiston

Surprise surprise! Fluid flow is turbulent. Hellooooo!

phlogiston

The massive pressure of water at the ocean floor forces it to adopt the temperature of lowest volume / highest density, i.e. close to zero. Its thermodynamically impossible for Trenberth to hide warm water at or near the ocean floor.