From the University of Utah and the “science is not settled” department comes this interesting bit of research.
Stratosphere targets deep sea to shape climate
North Atlantic ‘Achilles heel’ lets upper atmosphere affect the abyss
SALT LAKE CITY, Sept. 23, 2012 – A University of Utah study suggests something amazing: Periodic changes in winds 15 to 30 miles high in the stratosphere influence the seas by striking a vulnerable “Achilles heel” in the North Atlantic and changing mile-deep ocean circulation patterns, which in turn affect Earth’s climate.
“We found evidence that what happens in the stratosphere matters for the ocean circulation and therefore for climate,” says Thomas Reichler, senior author of the study published online Sunday, Sept. 23 in the journal Nature Geoscience.
Scientists already knew that events in the stratosphere, 6 miles to 30 miles above Earth, affect what happens below in the troposphere, the part of the atmosphere from Earth’s surface up to 6 miles or about 32,800 feet. Weather occurs in the troposphere.
Researchers also knew that global circulation patterns in the oceans – patterns caused mostly by variations in water temperature and saltiness – affect global climate.
“It is not new that the stratosphere impacts the troposphere,” says Reichler, an associate professor of atmospheric sciences at the University of Utah. “It also is not new that the troposphere impacts the ocean. But now we actually demonstrated an entire link between the stratosphere, the troposphere and the ocean.”
Funded by the University of Utah, Reichler conducted the study with University of Utah atmospheric sciences doctoral student Junsu Kim, and with atmospheric scientist Elisa Manzini and oceanographer Jürgen Kröger, both with the Max Planck Institute for Meteorology in Hamburg, Germany.
Stratospheric Winds and Sea Circulation Show Similar Rhythms
Reichler and colleagues used weather observations and 4,000 years worth of supercomputer simulations of weather to show a surprising association between decade-scale, periodic changes in stratospheric wind patterns known as the polar vortex, and similar rhythmic changes in deep-sea circulation patterns. The changes are:
— “Stratospheric sudden warming” events occur when temperatures rise and 80-mph “polar vortex” winds encircling the Artic suddenly weaken or even change direction. These winds extend from 15 miles elevation in the stratosphere up beyond the top of the stratosphere at 30 miles. The changes last for up to 60 days, allowing time for their effects to propagate down through the atmosphere to the ocean.
— Changes in the speed of the Atlantic circulation pattern – known as Atlantic Meridional Overturning Circulation – that influences the world’s oceans because it acts like a conveyor belt moving water around the planet.
Sometimes, both events happen several years in a row in one decade, and then none occur in the next decade. So incorporating this decade-scale effect of the stratosphere on the sea into supercomputer climate simulations or “models” is important in forecasting decade-to-decade climate changes that are distinct from global warming, Reichler says.
“If we as humans modify the stratosphere, it may – through the chain of events we demonstrate in this study – also impact the ocean circulation,” he says. “Good examples of how we modify the stratosphere are the ozone hole and also fossil-fuel burning that adds carbon dioxide to the stratosphere. These changes to the stratosphere can alter the ocean, and any change to the ocean is extremely important to global climate.”
A Vulnerable Soft Spot in the North Atlantic
“The North Atlantic is particularly important for global ocean circulation, and therefore for climate worldwide,” Reichler says. “In a region south of Greenland, which is called the downwelling region, water can get cold and salty enough – and thus dense enough – so the water starts sinking.”
It is Earth’s most important region of seawater downwelling, he adds. That sinking of cold, salty water “drives the three-dimensional oceanic conveyor belt circulation. What happens in the Atlantic also affects the other oceans.”
Reichler continues: “This area where downwelling occurs is quite susceptible to cooling or warming from the troposphere. If the water is close to becoming heavy enough to sink, then even small additional amounts of heating or cooling from the atmosphere may be imported to the ocean and either trigger downwelling events or delay them.”
Because of that sensitivity, Reichler calls the sea south of Greenland “the Achilles heel of the North Atlantic.”
From Stratosphere to the Sea
In winter, the stratospheric Arctic polar vortex whirls counterclockwise around the North Pole, with the strongest, 80-mph winds at about 60 degrees north latitude. They are stronger than jet stream winds, which are less than 70 mph in the troposphere below. But every two years on average, the stratospheric air suddenly is disrupted and the vortex gets warmer and weaker, and sometimes even shifts direction to clockwise.
“These are catastrophic rearrangements of circulation in the stratosphere,” and the weaker or reversed polar vortex persists up to two months, Reichler says. “Breakdown of the polar vortex can affect circulation in the troposphere all the way down to the surface.”
Reichler’s study ventured into new territory by asking if changes in stratospheric polar vortex winds impart heat or cold to the sea, and how that affects the sea.
It already was known that that these stratospheric wind changes affect the North Atlantic Oscillation – a pattern of low atmospheric pressure centered over Greenland and high pressure over the Azores to the south. The pattern can reverse or oscillate.
Because the oscillating pressure patterns are located above the ocean downwelling area near Greenland, the question is whether that pattern affects the downwelling and, in turn, the global oceanic circulation conveyor belt.
The study’s computer simulations show a decadal on-off pattern of correlated changes in the polar vortex, atmospheric pressure oscillations over the North Atlantic and changes in sea circulation more than one mile beneath the waves. Observations are consistent with the pattern revealed in computer simulations.
Observations and Simulations of the Stratosphere-to-Sea Link
In the 1980s and 2000s, a series of stratospheric sudden warming events weakened polar vortex winds. During the 1990s, the polar vortex remained strong.
Reichler and colleagues used published worldwide ocean observations from a dozen research groups to reconstruct behavior of the conveyor belt ocean circulation during the same 30-year period.
“The weakening and strengthening of the stratospheric circulation seems to correspond with changes in ocean circulation in the North Atlantic,” Reichler says.
To reduce uncertainties about the observations, the researchers used computers to simulate 4,000 years worth of atmosphere and ocean circulation.
“The computer model showed that when we have a series of these polar vortex changes, the ocean circulation is susceptible to those stratospheric events,” Reichler says.
To further verify the findings, the researchers combined 18 atmosphere and ocean models into one big simulation, and “we see very similar outcomes.”
The study suggests there is “a significant stratospheric impact on the ocean,” the researchers write. “Recurring stratospheric vortex events create long-lived perturbations at the ocean surface, which penetrate into the deeper ocean and trigger multidecadal variability in its circulation. This leads to the remarkable fact that signals that emanate from the stratosphere cross the entire atmosphere-ocean system.”
UPDATE: Although not listed in the official press release from the University of Utah here, I’ve located the title of the paper and abstract, reproduced below from Nature Geoscience
A stratospheric connection to Atlantic climate variability
- Nature Geoscience (2012) doi:10.1038/ngeo1586
The stratosphere is connected to tropospheric weather and climate. In particular, extreme stratospheric circulation events are known to exert a dynamical feedback on the troposphere1. However, it is unclear whether the state of the stratosphere also affects the ocean and its circulation. A co-variability of decadal stratospheric flow variations and conditions in the North Atlantic Ocean has been suggested, but such findings are based on short simulations with only one climate model2. Here we assess ocean reanalysis data and find that, over the previous 30 years, the stratosphere and the Atlantic thermohaline circulation experienced low-frequency variations that were similar to each other. Using climate models, we demonstrate that this similarity is consistent with the hypothesis that variations in the sequence of stratospheric circulation anomalies, combined with the persistence of individual anomalies, significantly affect the North Atlantic Ocean. Our analyses identify a previously unknown source for decadal climate variability and suggest that simulations of deep layers of the atmosphere and the ocean are needed for realistic predictions of climate.
Shown are composite anomalies averaged from day 0 to 60 following the strong vortex events of Fig. 2. Sea-level pressure anomalies are contoured at ±0.5, ±1, ±2, ±3, ±4 hPa; red and blue lines indicate positive and negative values, respectively.
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Looks interesting, but…
“To reduce uncertainties about the observations, the researchers used computers to simulate 4,000 years worth of atmosphere and ocean circulation.”
I would think that more physical measurements, not more computer simulations, would be the basis for reducing uncertainties. But hey, I’m just an engineer.
But overall, it sounds heretical, or ho hum; no direct support for AGW here. Move on, please.
If the study had finished with a sentence suggesting that added GHG were a catalyst for these sudden stratospheric wind events, then this might gain some traction in mainstream climate science.
Kurt in Switzerland
Very interesting, tho’ I note the care taken to disassociate from any possble undermining of global warming meme, and the reliance on models to prove the connection.
While agreeing with the general premise, there is some outstanding questions.
1. The study does not show any reasonable link between the vortex and affect on the Atlantic current?
2. The vortex can be influenced by low solar output, particularly UV which influences ozone distribution that can favor planetary waves traveling to the arctic vortex. Did they miss this bit?
Sorry, not impressed at all.Intuition or gut feeling, they have this totally reversed. By priming the models, they force the result they see. Again no physical observations, just models. added to which radiation warms the ocean not relatively slightly warmer air. The experts can nail.
Looks to me as complete nonsense. The bulk of the incoming heat is absorbed by the oceans, not the stratosphere. The mass in the stratosphere is tiny compared to the water masses of the currents redistribution the heat over the planet.
It’s like saying that you can heat a pan of water more efficiently by heating the air above it than by heating it’s bottom.
“The study’s computer simulations show a decadal on-off pattern of correlated changes in the polar vortex, atmospheric pressure oscillations over the North Atlantic and changes in sea circulation more than one mile beneath the waves”
Or vice versa?
Sounds like the new study has cause and effect backwards.
Schimanke et al (2011) found that it was the North Atlantic that caused the multidecadal variations in Stratospheric sudden warming events:
http://www.agu.org/pubs/crossref/2011/2010GL045756.shtml
Models again.
How do they determine that it is the Stratosphere that drives the oceans, not vice versa?
“Seems to correspond with” doesn’t sound very convincing.
Q: By what mechanism does CO2 cause the change in atmosphere & therefore what is the forcing factor used in the puter model?
Q: Hasn’t the conveyor belt theory already been thrown into chaos by not behaving as predicted, in a previous post either here or at Climate Realist?
I think the general findings seem reasonable, but why have they been linked to good old fashioned AGW & CO2?
“Good examples of how we modify the stratosphere are the ozone hole”
Do we????????
So.. there “might” be a correlation….
.
and as we all know, in climate science, this implies absolute “causation”,
even if it might be the wrong way around.
Also refer to the draft of Garfinkel et al (2012), which discusses ENSO’s influence on Stratospheric Sudden Warming events:
http://www.columbia.edu/~lmp/paps/garfinkel+etal-JGR-2012-inpress.pdf
This is yet another way that La Niña is not the opposite of El Niño. While Stratospheric Sudden Warming events were not discussed in my new book, they could be added to a list differing impacts of La Niña and El Niño.
It is an attempt to support AGW theory by getting around the ‘problem’ that the oceans control air temperatures and that CO2 warming of the air has little or no effect on the temperature of the ocean bulk.Their earlier ocean skin theory seems not to be sustainable.
Instead they suggest that somehow the stratosphere affects ocean temperatures by another route.
In that, they are getting close to my earlier propositions whereby changes in the temperature of the stratosphere (especially involving the polar vortices) can alter tropospheric climate zone positioning and thereby change global cloudiness and albedo to alter solar input to the oceans which would then affect ocean temperatures and circulation.
As usual it is then back to the issue of causation.
I propose that solar variations in the mix of wavelengths and particles (not TSI) naturally alter the ozone balance differentially at different heights to alter the vertical temperature profle of the atmosphere and thus the air ciculation patterns in the troposphere.
That is the main influence on cloudiness and albedo changes.
I have accepted that more CO2 in the air would have a similar effect on the air circulation but miniscule as compared to the solar effect combined with internal ocean cycles.
At least they have now figured out that a warmer stratosphere weakens the polar vortices and makes the jets more meridional.
Interestingly AGW theory previously said that human CO2 emissions were cooling the stratosphere thereby intensifying the polar vortices and leading to more zonal jets.
Now that the jets are more meridional despite still increasing CO2 they are here suggesting that somehow humans are warming the stratosphere over the poles.
They can’t have it both ways.
I think the truth is that an active sun cools the stratosphere naturally causing more intense polar vortices which contract and pull the jets and climate zones poleard allowing more solar energy into the oceans.
That extra solar energy into the oceans skews ENSO in favour of warmer El Ninos and that is what affects ocean circulations.
The opposite when the sun is quiet.
Teleconnection.
Could somebody please tell me why the immense Great Southern Ocean and the South Pacific Oceans and all of the Southern Hemisphere apparently has no influence on the global climate nor it seems has any connection with the global atmosphere and climate?
The one eyed concentration by most Northern Hemisphere based so called climate researchers on Northern Hemisphere phenomena and then claiming that those same Northern Hemisphere phenomena are the cause of all the changes in the Earth’s climate are a striking example of scientific ignorance and stupidity when the immense mass and heat content of the Great Southern Ocean and the Southern Pacific Ocean are looked at even by a layman.
The heat energy content of the global atmosphere is matched by the heart energy in the top 3.2 metres of the world’s oceans.
From this figure alone it would seem that the Oceans, most of which global Oceans are concentrated in the Southern Hemisphere and what happens via the medium of the Oceans are the true influences and controllers of the global climate.
Take one of those globes of the world on it’s stand.
Place the globe stand high enough so that the bottom of the globe is a little above eye level and Antarctica is pointing directly at you.
Rotate the globe until you have the entire Southern Pacific Ocean and the large part of the Southern Ocean facing directly at you.
Step back a couple of paces and take a look.
When the globe is rotated to the right position you will see Antarctica and New Zealand in their entirety and these will be the only complete land large masses you will see.
You will also see just the edge bit of eastern Australia and the west coast of South America and that’s it for major land masses in that sector of the planet.
And what you see is almost totally ignored by narrow tunnel visioned northern hemisphere based climate researchers who seem incapable of even considering that there may be other very major influences in other remote parts at world at work on the global climate other than those that that exist just outside of their own back door.
Isn’t the mind an amazing place to have an adventure.
This looks backasswards to me. Given the huge disparity in heat capacities and the very small surface-area-to-volume ratio, it seems highly improbable that a small change in air temp could have much effect on the massive water column.
Maybe I should try running a bath of cold water and letting the warm room air heat it up for me??!!
They have the tail wagging the dog as usual, do they have no common sense?
is known what happpend to Jo Nova’s account ?
Bob Tisdale says:
It seems everything is about your book theses days.
@ur momisugly Alan the Brit
”
I think the general findings seem reasonable, but why have they been linked to good old fashioned AGW & CO2?”
Because its from the Potsdam Institute. !!
Since when has a correlation between two processes implied that one is the cause?
Geoff Sharp:
“The vortex can be influenced by low solar output, particularly UV which influences ozone distribution that can favor planetary waves traveling to the arctic vortex. Did they miss this bit?”
Yes, – elsewhere, I have argued for several years now that the North Atlantic is a very important key area to the seasonal weather of the northern mid-latitude land masses – winter cold and summer warmth: and now explained probably, by the mechanism of the Hadley Cell, seemingly affected and re-orientating and connected to ozone distribution influenced by the changing UV output of the sun and whether the direction of the jet stream as it approaches Europe, is mostly from the south west or north west, (being essentially NW when the sun is inactive and SW when the sun is active).
The jet stream NW vector results in a tendency for earlier snow cover in autumn and later snow melt in spring in northern Eurasia, with resultant regional cooling.
My question is whether there is any/much agreement that the new research about ocean current, climate changes and stratospheric circulation changes, could indeed correlate and connect with the UV/ozone distribution research and “favor planetary waves travelling to the arctic vortex”, and which would perhaps be the reason for the multi-decadal but not exclusive variations between northern hemispheric meridional/zonal circulation patterns?
Put another way, the Azores high at times of low sun activity, stands as a big rock just to the south of the polar vortex jet stream and causes ripples by way of planetary waves that have influences to northern hemisphere weather that are not just regionally European.
As one who spent two years investigating all available data relating to the north Atlantic and managed to reproduce the Atlantic Multidecadal Oscillation, more accurately then Gray and Mann I can with a degree of confidence claim that they got this upside down.
Events that happen well below the ocean surface are one of the two key elements that change the North Hemisphere temperature. The other is the sun of course, but not the TSI, there is not much of it up there for 6 months of the year.
This is not a model of the past, but actual data from the past of the variables I just mentioned:
http://www.vukcevic.talktalk.net/GSC1.htm
What about the Mann claim?
http://www.vukcevic.talktalk.net/AMO-recon.htm
Some more research is probably warranted and it would be interesting to see if there was any comparable phenomenon at the South Pole. However, I’d be leaving the supercomputer at home and looking for empirical evidence.
Also, I think I can detect a faint smell of dinosaur farts.