Hexagon on Earth?

Most of us have heard about the hexagon pattern seen in polar jet flow on Saturn. In doing a lot of different views of the Earth on Nullschool, I’ve managed to catch a picture of a sort of a hexagon on Earth. Right now the same view looks more like a square, so it does change over time, at least for Earth.

IMHO, this is an artifact of the projection where curvature of the jet around cyclones gets made into straight lines in the projection. But that just suggests that perhaps the same thing could be happening with the Saturn polar projection and that “hexagon”. What does it look like when put into an equatorial projection, eh?

Polar view of Earth from Nullschool at 850 mb temperature data 10 Nov 2014

Polar view of Earth from Nullschool at 850 mb temperature data 10 Nov 2014

Unlike Saturn, this hexagon is showing up in the far polar pattern while the near polar jet looks very ‘loopy’. IMHO this is a clue as to the degree of ‘loopy’ and nature of the projection needed to make a hexagon out of curving flow. Also, the Earth pattern is more irregular, likely, IMHO, due to the effect of land forms and our more shallow atmosphere layer.

Unfortunately, I don’t have an equatorial projection from exactly that same day ( I thought I saved one, and it might be buried somewhere, but is not to hand at the moment). Here is one from a nearby date, and, as I recall, things were not that different between the two dates.

Sea Temps EQ 850 mb temps 7Nov2014 110pm

Sea Temps EQ 850 mb temps 7Nov2014 110pm

Note the tendency for similar sized cyclonic air patterns spacing at similar distances from each other around the South Pole. That in my opinion is what is happening on Saturn, but deep enough that it has regularized by the time it is above the cloud level and much more stable in a gas giant.

In summary, I don’t think this is an answer, but I think it points in the direction of one. When the various heat moving cyclones cozy up to a pole, they close pack into a set of six. These, then, curve the air flow around them. At some strength and distance from the pole, the polar projection straightens out those curves into a hexagon. But in the real world it’s wavy in a projection from the side. IMHO a natural consequence of heat flow leading to minimal energy systems dumping heat to the poles. Likely to show up whenever the heat balance is in a particular range that makes that many cyclones that close to the pole.

Or perhaps this was just a lucky catch of an optical illusion ;-) But a pretty one…

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About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
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11 Responses to Hexagon on Earth?

  1. craigm350 says:

    Chiefio did you mean like this?

    http://earth.nullschool.net/#2014/11/10/2100Z/wind/isobaric/850hPa/overlay=temp/equirectangular

    You can change YYYY/MM/DD in the link above.

    Saturn’s hexagon doesn’t half remind me of cymatics, so I look at the solar cycles as a change of ‘frequency’ changing the shape (zonal vs meridional jet) but complicated as you say by atmosphere and landmass*. I was in part struck with this when Gail Combs and Tony Heller were commenting on the on the similarity of the Laurentide sheet and the Polar Vortex.

    * Speaking of the Jetstream – and Saturn – Tim Cullen has a recent interesting series on Couette flow

    http://malagabay.wordpress.com/2015/01/29/couette-flow-3-turbulence/

    A subsequent piece looking at Taylor flow – or the tubes – reminded me of an images of the polar and subtropical jets.

  2. E.M.Smith says:

    @craigm350:

    Yeah, like that… Ya caught me being lazy ;-)

    ( I though there was a way to pick a date, but was being too lazy to figure it out. I’d already sat on the idea of this posting since last November and wanted to “get it out there” before it was ancient history… so moved ‘fast not deep’ on the actual posting…)

    On the topic of votex ubiquity… there is the Kasper wing… Here’s a video of a bird like robot:

    Birds use a vortex at low speed…

    A discussion of the ‘trapped vortex” here:
    http://www.secretprojects.co.uk/forum/index.php?topic=4935.0

    The book (no image at Amazon) http://www.amazon.com/The-kasper-wing-Witold-Kasper/dp/B00072AEKW

    Stable no-tail flying wing ultralights using it (video has strange music, IMHO)
    http://kasperwing.com/

    http://www.kasperwing.com/Kasperwing%20History.htm

    The Kasperwing Ultralight is a collaborative design between Polish sailplane pilot and aerodynamicist Witold Kasprzyk (pronounced Vee-told Kasper) and American hang glider designer / entrepreneur Steve Grossruck. Kasper had won Poland’s national sailplane championship on four occasions before World War II and had been working for several decades on a way to increase airplane safety and performance by developing a flying wing (tail-less) platform that utilized a type of high energy span-wise vortex to increase lift; in conjunction with a control system that functioned independent of forward airspeed (see patent #’s 3,438,597 and 3,831,885). The purpose of these improvements was to reduce drag, enable an ultra-slow landing speed and at the same time avoid some of the classical “stall-spin” problems of conventional tailed aircraft.

    The great distinction between the Kasper platform and other tail-less aircraft is in the way the control system functions. Kasper had analyzed the advantages and shortcomings of the earlier flying wings of the time, such as those developed by the Horton brothers or John Northrop, and decided improvements could be made in the areas of stability and control. To do this he utilized a reflex airfoil, low twist constant chord wing and employed adjustable upswept horizontal stabilizers at the wingtips for pitch damping and to prevent tip stalling. The vertical winglet surfaces are a two- piece system consisting of a moveable rudder with forward balance tab/spoiler and fixed vertical stabilizer. The combination is canted outboard and toed inward to provide exceptional yaw and roll stability. Due to the canted geometry, the rudder acts like an aileron, rudder and spoiler when deployed and automatically coordinates turns. The winglet provides additional lift by increasing the effective aspect ratio, cuts drag by reducing the wingtip vortices and gives control that does not depend on the aircraft’s forward speed in order to function, unlike conventional aircraft control systems. The pilot could raise the nose of the wing, gently pass below the normal stall speed and settle into a near vertical descent or “Mush” and still maintain complete yaw and roll control. Kasper felt the system more closely resembled the way birds control their flight and noted “birds rarely stall and crash”. An airplane with this type of control system would perform better and be safer as a bonus.

    with a lot more technical detail…

    The Vortex… it’s your friend…

  3. Jason Calley says:

    Years ago I was reading about an experimenter who was pulsing HUGE currents through circular wire rings. The currents were so large that the ring’s own magnetic field would fracture the wire into pieces. Six pieces. Almost every time…

    I wonder if there is some connection.

  4. Jason Calley says:

    Just a bit of hand waving regarding my post just above…

    If the tension generated by a magnetic field breaks a ring into six parts, here is a moderately plausible reason why a planetary vortex might also show some six-fold features. Consider a circular jet stream around either pole. This stream is also circulating around a magnetic pole. Homopolar induction within the stream will create an electric field at right angles to both the magnetic field lines and the direction of jet stream circulation. In other words there will be an electric field running roughly north-south and (for areas with a high magnetic field inclination) roughly parallel with the surface. Of course the jet stream does not have nearly the tensile strength of a piece of wire, so it will be less difficult to distort. Maybe the electric field across the stream is enough to give that six-fold symmetry — which still does not tell us why “six” and not “five” or “23”…

  5. p.g.sharrow says:

    @Jason; Emmmm…. you may be on to something. The EMF of the Earth field would tend to try to force the Jet into a straight line that would “break” at some point. Everything has inertia even electrons. This stuff would tend to move in a straight line until the turning force exceeded the inertia and forced the turn. A faster “wind” would exhibit straighter lines with sharper turns, a more pronounced “hex”. pg

  6. p.g.sharrow says:

    The 6 sides is the results of the twist caused by the 3 vectors of EMF . Think in 3 dimensions on a globe. pg

  7. R.de Haan says:

    Potential explosion of new temperature groundstation (weather stations) network at schools thanks to a Rasberry PI project: http://www.raspberrypi.org/school-weather-station-project/

    The Rasberry PI 2, FreeNas, OpenBTS, the tools of independence.

  8. E.M.Smith says:

    @R. de Haan:

    Nice use for a R.Pi…

    @Jason:

    Hmmm….

    Thinking of soccer balls with hexagons and pentagons and wondering ‘why?’…

    @P.G.:

    You expect me to think in 3 D with 3 EMF vectors and 6 segments on a spherical surface? And me out of wine? (Though other visually active ‘aids’ might be more helpful ;-)

    I think my brain hurts…

  9. p.g.sharrow says:

    @EMSmith; Sorry :-(

    My 17 year old grandson and I have just bought a bunch of R.Pi’s and needed add ons and he expects me to get up to speed on them as well as the Plan9 OS. To get up to speed on computer stuff one more time makes me cringe at the thought. :-p Wonder if there is enough room in this old brain for another LARGE box load of knowledge! pg

  10. E.M.Smith says:

    I have 2 R.Pi with me and Plan 9 on a chip somewhere… maybe I’ll try to install it and see what happens ;-)

    I do find it easy to have lots of knowledge when I leave it in a box, so a “LARGE box” is not the problem… it’s the amount I can swap into ‘stickyware’ that’s the problem ;-)

  11. Jason Calley says:

    I was watching a video of a guy’s experiments and theories about magnetic fields. He had two half spheres charged to a high potential voltage and ionizing gas in a chamber. When he pulled the hemispheres out of the chamber, the end had a nice hexagon… See the 11:45 mark.

    I have not watched the whole video yet, and so have no opinion on the correctness of it’s theory.

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