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Earth Science

Ocean Circulation Doesn't Work As Expected 658

techno-vampire writes with word that a long-accepted model of deep ocean currents is inaccurate. Deep Sea News has a summary of the research, to be published in Nature. The Woods Hole press release has more details. "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 1990s, and likely plays havoc with global models of climate change."
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Ocean Circulation Doesn't Work As Expected

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  • by Anonymous Coward on Friday May 15, 2009 @11:00AM (#27966783)

    aren't accurate? For Gore's sake, what a surprise!

    • by N1ck0 ( 803359 ) on Friday May 15, 2009 @11:23AM (#27967217)

      Ocean current that might vary in flow and not exactly match models that are decades old...sheesh. Don't they teach kids how to do fluid dynamics calculations with billions upon billions of variables all of which change over with time and depend on a multitude of other models which themselves have varying levels of accuracy to their data these days.

      • by hey! ( 33014 ) on Friday May 15, 2009 @11:37AM (#27967533) Homepage Journal

        sheesh. Don't they teach kids how to do fluid dynamics calculations with billions upon billions of variables all of which change over with time and depend on a multitude of other models which themselves have varying levels of accuracy to their data these days.

        My wife went to grad school in physical oceanography (at WHOI, it turns out).

        One of my MIT buddies was this guy who pretty much finished up course 18 (Mathematics) undergrad requirements at the end of his sophomore year, and spent the next two years studying these really thin, expensive, and badly printed books of what looked like the output of a line printer on the wrong parity setting. I knew my then girlfriend was in trouble when I told this guy what she was studying and he was impressed.

      • Calculations! Huh! In my day, we solved Thermodynamic Navier-Stokes equations analytically or we didn't solve 'em at all. Yes sir, if you wanted something done right you had to solve it by hand! None of these razzle dazzle calumalators. We derived systems of diffeo-integral equations from first principles, solved them using power series with Bessel's Functions and we liked it!

        Boundary conditions!? Hah! We used elliptic integrals and n^th order polynomials to generate our boundaries. None of your hoi polloi "splines" and "fractals". What good's a function that's not 10^th order continuous, I ask yah?! Bunch of whippersnappers! Let's see how your spline deals with my 4^th order constraint! Hah!

        Floating point?! What luxury! In those times, if you wanted some numerical results, well sir, you had to generate an asymptotic series out to fifteen terms, and calculate your answer using surds and continued fractions, uphill both ways. In the snow. Course if you were lucky, you might get your 5 minute turn with the shared slide rule. That is, if it wasn't rusted up from the damp and cold. Great days.

        "Billions upon billions of variables". You youngsters and your numerical models. Nothing gained that couldn't have been got from one afternoon with a fluid dynamics problem set. No wonder the world's gettin' warmer with all the HOT AIR comin' out you an all your bippity-boppity, hankly-pankly, good for nothin' electromonic computers !!

    • Driving Blind (Score:5, Insightful)

      by StCredZero ( 169093 ) on Friday May 15, 2009 @11:27AM (#27967307)

      In other words, now we don't know what might happen and we're *still* mucking with our climate.

      • Re:Driving Blind (Score:5, Interesting)

        by commodore64_love ( 1445365 ) on Friday May 15, 2009 @11:39AM (#27967563) Journal

        Today's oil and coal was once carbon dioxide that floated in the atmosphere. What was life like back then? Pretty much the same as now, but more tropical. Giant reptiles roamed the planet, while smaller reptiles (proto-mammals) scurried underfoot. It was one of Earth's most-productive periods and a great time to live, not a tragedy.

        I think global warming, if it happens, will be great. No more frozen Canada or Siberia - we can settle those lands and grow more food than in the entire existence of humankind. It requires adaptation, not fear.

    • by geoffrobinson ( 109879 ) on Friday May 15, 2009 @11:43AM (#27967657) Homepage

      Being skeptical of scientists giving dogmatic claims of incredibly complex weather systems with billions of variables, known and unknown, sounds like Denier talk to me. Either that or you are obviously under the employ of oil companies, Dick Cheney or you are the guy who controls Karl Rove's weather machine. The one Bush used to destroy New Orleans.

    • by ksheff ( 2406 ) on Friday May 15, 2009 @12:05PM (#27968127) Homepage
      The place I used to work at 15 years ago created global land cover classification maps based on satellite data. When they started creating their 1km resolution maps, a few GC scientists got pissed since the data broke their climate models. It seems their assumptions of what the land cover was like for different areas of the planet were quite different from observed reality.
  • by Gothmolly ( 148874 ) on Friday May 15, 2009 @11:04AM (#27966849)

    Clearly this is a product of Western materialism. However, Al Gore will stop at nothing to demonstrate our danger:

    http://www.theonion.com/content/news/al_gore_caught_warming_globe_to [theonion.com]

  • by crypTeX ( 643412 ) on Friday May 15, 2009 @11:04AM (#27966855)
    Despite the fact that we didn't have accurate data about the pattern of ocean currents earlier, we can now welcome panicked decrees that we are changing the pattern of ocean currents!
  • "long accepted" (Score:4, Informative)

    by Anonymous Coward on Friday May 15, 2009 @11:05AM (#27966883)
    Something that everyone should keep in mind with nearly any theory regarding earth science -- "long accepted" doesn't go back very far. Most "modern" geologic (and oceanographic) theories only go back 40 or 50 years. When compared to the other major scientific fields, that's not very long at all. Hell, we've understood nuclear fusion and fission longer than we've understood the basic mechanics of the Earth.
  • what a suprise (Score:5, Insightful)

    by wjh31 ( 1372867 ) on Friday May 15, 2009 @11:08AM (#27966941) Homepage
    who would have ever guessed that we would have trouble forming an accurate model of a vast, complex, chaotic system
  • I love science (Score:5, Informative)

    by SoupGuru ( 723634 ) on Friday May 15, 2009 @11:20AM (#27967149)

    Damnit, I love science!

    This is how it's supposed to work.

  • These results don't say that global warming is occurring. In fact, they neither support nor oppose the idea at all. The Woods Hole press release [eurekalert.org] is fairly neutral:

    And since this cold southward-flowing water is thought to influence and perhaps moderate human-caused climate change, this finding may impact the work of global warming forecasters.

    "May impact the work of global warming forecasters" is true; it might also influence the thinking of UFO chasers but that won't help determine whether they're piloted by little green men. This research will complicate models designed to model the specific effects of global warming. Given how much is unknown yet, and how much has yet to be determined by human activities (to the extent that we choose to mitigate or fail to mitigate our impact on the biosphere) those models are already only potentially correct by marvelous coincidence anyway.

  • Um, not quite. (Score:5, Informative)

    by Anonymous Coward on Friday May 15, 2009 @11:22AM (#27967181)

    IAAPO (physical oceanographer).

    The quoted blog is being a little over-excited about this. There's nothing in WHOI's press release that suggests that this brings the thermohaline circulation tumbling down, and certainly nothing to play "havoc" with climate models. Quoth the press release:

    And since this cold southward-flowing water is thought to influence and perhaps moderate human-caused climate change, this finding may impact the work of global warming forecasters.

    "This finding means it is going to be more difficult to measure climate signals in the deep ocean," Lozier said. "We thought we could just measure them in the Deep Western Boundary Current, but we really can't."

    In other words, the circulation is there, but it's more diffuse that expected, and so you can measure it by looking at a well-defined path along the continental shelf as expected. That requires some revamping of theory, and will make circulation model validation and data assimilation more difficult, but that's all.

    The DWBC has an interesting scientific history -- it's one of the few ocean phenomena predicted by theory before it was observed, in part because its depth and slowness prevented observation.

    But, hey, never mind, Al Gore, manbearpig, lalala I can't hear you.

  • by idontgno ( 624372 ) on Friday May 15, 2009 @11:32AM (#27967419) Journal

    the one that heralds new discoveries, is not 'Eureka!' but 'That's funny...'"

    -- Isaac Asimov

  • by LordKaT ( 619540 ) on Friday May 15, 2009 @11:34AM (#27967477) Homepage Journal

    Science: "We've observed that the Earth's climate is getting warmer by nearly a full degree Celsius over a period of observation of around 200 years. We've noticed a correlating increase in CO2 emissions in that timespan."


    Science: "But the Earth is 4.54 billion years old, so our dataset is incomplete."


    Science: "Of course, we've seen in tests that increasing the level of CO2 in an environment can significantly increase the temperature of an environment."


    Science: "One of the leading theories we have as to the increase in global temperatures is this so-called 'blanket-effect'"


    Science: "On the other hand, it's still a possibility that we're in a natural cycle of global warming. We saw a similar pattern in history, which occurred right before we experienced a miniature ice age."


    Repeat until you either change the channel or become so psychotic from the endless political bashing that you go out and kill 50 or 60 people, just to relieve the stress.

  • Evaporation... (Score:4, Interesting)

    by dtjohnson ( 102237 ) on Friday May 15, 2009 @11:54AM (#27967889)

    Reading the news release makes it sound as if the problem was that the expected deep ocean return current was just in the wrong location. They put the floats in the areas where the current was supposed to be and only 8 percent of them actually even went in the 'right' direction. So...their 'conclusion' is that the current is just in the 'wrong' location but that it still exists, although they have never actually observed it. Without being any sort of climate 'expert' it seems obvious that evaporation of water in the northern latitudes is a far more important contributor to the gulf stream flow than the hypothesized deep ocean return current. It even seems probable that most of the evaporation of water on this planet occurs in the northern and southern latitudes. In that model, warm water flows north and south around the planet from the equatorial regions towards the poles and evaporates, thereby cooling the ocean waters and transferring heat and moisture into the atmosphere where it eventually falls as precipitation as it moves back towards the equator. Of course, this evaporation model cannot be correct because it allows the atmosphere to be a major conveyor of heat (as vapor phase water) which does not fit well with the 'greenhouse gas' idea in which the earth is surrounded by atmospheric gases which are blocking the radiation of long-wave infrared radiation into space, thereby warming the earth. I don't think there are any Eisteins in the atmospheric sciences field at the moment.

  • by bhima ( 46039 ) * <Bhima.Pandava@gmail. c o m> on Friday May 15, 2009 @12:03PM (#27968071) Journal

    I am a nature subscriber and I just read the letter which this crap is 'based on'. In what I find to be depressing regularity the content in Nature Magazine is misrepresented. Presumably because some of the content at Nature.com is only available to subscribers.

    So the title of Slashdot submission is wrong. The summary and free article at deepseanews it is based on mischaracterize the content of the letter. And naturally most of the comments here on Slashdot don't take into account the article, the letter, or anything that smells to much like reality.

    If anyone is particularly interested the study found additional new details about ocean currents which the suggest should be included in future model of global ocean currents. This isn't especially exciting but I suppose it's interesting from a point of view of making our understanding and models more complete.

    So nothing there about ocean circulation not working the way scientists have described (or a "a major paradigm shift in ocean circulation theory.") Nothing there about failure of models. Nothing there about climate change being either true / not true or stronger / weaker.

    This is just what most science is all about... making current understanding more complete or more correct. Below is the excerpt, which I believe to be publication available.

    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 2003â"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.

  • In Short... (Score:4, Insightful)

    by Nom du Keyboard ( 633989 ) on Friday May 15, 2009 @12:11PM (#27968261)

    ...and likely plays havoc with global models of climate change.

    In short, we don't know what's really happening, but our political leaders are making very expensive decisions based on the belief (of some) that we do.

    That's a great textbook definition of Stupidity!

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