Thursday, December 13, 2012

Big Cooling

Just a quick post showing the dramatic cooling during the day Thursday in Fairbanks, with the 3am vs. the 3pm upper air soundings. That's a lot of cooling in the lowest 1000 meters in just 12 hours. Here on the hill, the high today was 26F, about 3am, and as of 5pm it was -1F.

4 comments:

  1. Here's a link to the recent cooling trend for Alaska noted by the authors during the last decade:

    http://www.benthamscience.com/open/toascj/articles/V006/111TOASCJ.pdf

    I wonder if an "s" will have to be added to "Decade" in future years.

    Gary

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    1. Gary,

      I've had a couple of conversations with Professor Wendler about this. My take, which is touched on in the paper, is that this reflects the 2007 shift in the PDO from positive to negative phase (so sea surface temps, on average, went from above normal to below normal along the northwest North American coast). However, as the graphics in the paper demonstrate, and you know from your long experience, temperatures have not returned to the pre-1976 levels.

      Also, this analysis, using first order stations, is biased (in a statistical sense) to locations that are close to the Gulf of Alaska/North Pacific and so are strongly impacted by near shore sea surface temperatures. Northern and Interior Alaska are unrepresented in this kind of analysis scheme. The effect is to amplify the PDO effect.

      Rick

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  2. The PDO driver, or whatever it was, has had a dramatic effect on our climate for several years. We are warming overall, the North Slope more than the Interior, despite this slight cooling trend over the last decade.

    I agree on the data bias. They chose to exclude for whatever reason. Maybe the correlation coefficients were adversely impacted. Not sure.

    Regardless, the PDO versus fisheries (my field) has been well documented. The question that lingers is what drives the PDO? Somewhere I've read that the cooling trend may reverse in a couple more years (Japanese projections). I hope so.

    Gary

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    Replies
    1. Gary,

      If you have not seen the PDO link from Alaska Climate Research Center (Gerd Wendler's shop), here it is:

      http://climate.gi.alaska.edu/ClimTrends/Change/TempChange.html

      I may have down a PDO post some time in the past but I'll put up one when I get a chance.

      Rick

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