Friday, March 5, 2010

North Pole's polar vortex virtually non-existent in February 2010

This is not something that we want to see occur very often:

Vertical Cross section of Geopotential Height Anomalies Banner
The daily geopotential height anomalies at 17 pressure levels are shown for the previous 120 days as indicated, and they are normalized by standard deviation using 1979-2000 base period. The anomalies are calculated by subtracting 1979-2000 daily climatology, and then averaged over the polar cap poleward of 65° N.

The blue (red) colors represent a strong (weak) polar vortex. The black solid lines show the zero anomalies.
Link:  http://www.cpc.noaa.gov/products/precip/CWlink/daily_ao_index/hgt.shtml
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9 comments:

  1. susanMarch 5, 2010 at 8:55 PM

    but, sigh, what does it mean. I wish I could understand these things better!

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  2. Tenney NaumerMarch 5, 2010 at 9:17 PM

    I'm not sure either, but we pretty much saw what happened when it went negative for so long -- the effects were severe in many regions all over the Northern Hemisphere. I am thinking we need that polar vortex to be up there, most of the time.

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  3. jyyhMarch 5, 2010 at 11:54 PM

    I see it like this:polar vortex is part of the system that includes the arctic front (in the surface), in the absence of it the mixing of Arctic and midlatitude air is stronger than usual, means warmer temps in the arctic cooler in midlatitudes. As a result the Arctic sea ice is a tad warmer than previously and I'm expecting the ice to melt quite rapidly early in the season. Can't help but thinking this is somehow related to the methane releases on the sea bed, but couldn't figure out what the actual mechanism could be.

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  4. Tenney NaumerMarch 6, 2010 at 5:59 PM

    I have a strong tendency to look at these things in terms of the planetary water vapor streams. Heat is pumped out at the Equator and it is transported toward the poles.

    This warmer moist air is pushing the cold dry air out of the Arctic.

    It used to be that the cold air up there served as a sort of a protective cap, but over time, it too has warmed and weakened.

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  5. Tenney NaumerMarch 6, 2010 at 6:01 PM

    I have a strong tendency to look at these things in terms of the planetary water vapor streams. Heat is pumped out at the Equator and it is transported toward the poles.

    This warmer moist air is pushing the cold dry air out of the Arctic.

    It used to be that the cold air up there served as a sort of a protective cap, but over time, it too has warmed and weakened.

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  6. GarethMarch 8, 2010 at 5:44 PM

    Tenney, I don't think this is a measurement of the polar vortex. The graphics refer to the North Atlantic Oscillation (aka the Arctic Oscillation), which is a measure of the intensity of the pressure gradient between the Icelandic Low and the sub-tropical high pressure further south. What it shows is that the NAO has been in record-breaking negative territory twice this winter. Check out the graphic here and here.

    The polar vortex is an upper atmosphere feature, described here. I posted a great NASA visualisation of a polar vortex break-up last year. Note the NASA description - the two features can interact...

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  7. Tenney NaumerMarch 9, 2010 at 9:59 AM

    Dear Gareth,

    Thanks for this info.

    The thing is, I look at the world's weather with regard to the 3D, dynamic streams of water vapor that encircle the globe.

    Until recently, these things were only described in terms of pressure gradients.

    But they are streams of water vapor and they carry energy from the Equator to the poles.

    As they go closer and closer to the poles, the space they have to occupy becomes smaller and smaller.

    Something has to give.

    This winter, the warm moist air pushed out the cold air at the North Pole.

    Last February, there was apparently so much hot air up there that it blew out like an enormous belch, straight through the polar vortex.

    Recently, NASA has posted an animation of the planetary water vapor from something like 2002 through 2009.

    If you look at the North Pole during the animation, you can see that there is a yearly accumulation that seems largest in the winter, and then it goes away. Perhaps the polar vortex is often split in February. I suppose that we do not have enough years of satellite data to know.

    Have a look here where you can download the QuickTime animation:

    http://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MYDAL2_M_SKY_WV

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  8. GarethMarch 9, 2010 at 5:08 PM

    I asked meterologist/climatologist friends about the polar vortex last year: apparently break ups are not that uncommon - but they're usually a spring event. Last year's was rather early.

    What you're basically interested in is something that fascinates me - the way that the "pattern" of weather is changing as the planet accumulates heat. We know that in the past the system has been prone to rapid reorganisations (the Younger Dryas, for instance, probably started in one season) - it can flip into a new pattern. That could deliver dramatic climate change in some places, but not everywhere at the same time. Are there early warning signs? Possibly -- but we not recognise them until after the event.

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  9. Tenney NaumerMarch 10, 2010 at 10:06 AM

    Gareth, I think the signs are here. The forcing on the system is so great and so rapid that (based on the research that has been coming out over the past 12 months) it appears to me that we have pushed past the point of no return. If you look at the satellite temp data, you can see that the signal has clearly and in no uncertain manner risen above the noise.
    http://discover.itsc.uah.edu/amsutemps/

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