Sunday, December 7, 2014

-40° Reached

The first measured -40° temperature of the season (as far as I'm aware) was observed in Alaska this morning, as the thermometer at Toolik Field Station registered -42 °F at 2am AKST.  A couple of sites came close to this benchmark of winter cold on November 28 (-36 °F at Arctic Village, -35 °F at Chicken).  Here's an infrared image from the Suomi-NPP satellite at 0516 AKST this morning, with the location of Toolik Lake indicated; it looks like many locations north of the Brooks Range were at least as cold.



It's late in the year to be observing the first -40° temperature, but there have been 7 years since 1950 in which it occurred even later; the 1950-2013 record latest was in 2002, when -40° was not reached until December 30.

The first -40° temperature of the season is most often observed at places such as Allakaket, Bettles, Umiat, Chandalar Lake, and Northway.  Historical data from Toolik Field Station began in 1988, and that year was the only other year in which Toolik was the first place to reach -40°.

Here's the Toolik webcam image looking south an hour before solar noon today.


14 comments:

  1. The Ivotuk CRN reached -40 just 20 hours later.

    A strengthening pressure gradient is pushing the cold air over the Brooks Range passes, with the now-infamous Howard Pass RAWS recording -31F with 51mph sustained wind this morning.

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  2. At 9:39am 12/8 Howard pass was reporting -31F, a -80 chill, with winds NNE 69G77.

    The 6AM NOAA-19 Sat IR shows NE flow through all the nearby passes:

    http://pafg.arh.noaa.gov/arhdata/sat/hrpt/14342145822/4f1f.jpg

    That area (the Noatak River Drainage) was occupied for thousands of years by early immigrants from Siberia. They established camps near Howard Pass at Burial, Feniak, and Desperation Lakes in pursuit of migratory Bison and Caribou. How they survived the elements is amazing.

    Some archaeology:

    http://www.nps.gov/archeology/sites/npsites/noatakVillages.htm

    Gary

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    Replies
    1. Gary, thanks for the link.

      "The people living at these sites were not simply surviving in this high arctic environment where the resource base is limited in quantity and breadth, but they were apparently flourishing."

      Although I'm sure they had the sense to head for the sheltered lowlands during winter.

      Winds now up to 75G82 at the pass. Wonder how many years it will be before NPS tires of replacing the anemometer each summer.

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    2. Here's a good MS Thesis read that describes the seasonal behavior of late Holocene/pre-contact Noatak River residents. Some apparently lived near the large lakes west of Howard Pass during the winter from choice. That's of course providing the food supply was available. After the contact period most moved to settlements near the coast. I've been to all three of the lake sites years ago doing fisheries studies in that area.

      http://www.academia.edu/4750398/

      The winds are formidable and the Thesis discusses wind scouring with pictures during winter.

      Gary

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    3. Unless there was a transmission glitch the anemometer quit after 2:39 pm AKST 12/8. Did it blow up? Hope not.

      The NPS may soon need to install an industrial unit capable of 100+ mph gusts. Or at least one designed to be capable of withstanding flying debris that could damage the unit or propeller.

      Gary

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    4. It does appear to have gone down, what a shame. Last year we made it until mid-February and survived slightly stronger winds.

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    5. I suggest it was damaged by flying debris. The sensor should tolerate that level of wind.

      The knoll it sits on is very likely scoured from the extreme winds, consequently is poorly vegetated, and any exposed surface material would be easily carried aloft via aeolian drift.

      To survive it may need to be installed higher to get above the majority of the blown surface particles, or a different design of anemometer installed.

      That spot would be a good candidate for a CRN setup given its unique climate providing the instruments could withstand the elements.

      Gary

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    6. To see the site and instruments go to this link:

      http://gmap3d.com/?d=1403570&s=AK&f=gap

      With your cursor set the Lat-Long coordinates at the bottom of the map's page to the following. The station is SE of the initial view the link provides:

      68 11' 34.00"N 156 50' 42.72W It's white with darker shadows behind. Note the scoured surface of the knoll it sits on.

      Gary

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    7. Gary, thank you for sharing the information about the site via your comments. I spoke with the NPS folks that manage the site back in August about obtaining the raw station data and they generously provided it to me (yesterday) along with pictures and some equipment metadata. As alluded to earlier, there have been a number of very extreme events at this location recently (and before that of course). In addition to the (in)famous -97°F wind chill, there is an even lower reading from the previous winter. I plan on a blog post about the earlier event in the next few days and I will be incorporating some of the information that you contributed through the comments; with attribution.

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    8. Gary, thanks for the link to this neat site. Very impressive technology.

      Brian, I look forward to the post!

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    9. Look at the amazing wind spillage through the Howard Pass area on this IR shot:

      http://pafg.arh.noaa.gov/arhdata/sat/hrpt/14343230253/4f1f.jpg

      That's a truly adverse location for wind chills. It's -31F at ~11:00 pm with undocumented winds and gusts.

      Gary

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    10. One more comment regarding the Noatak River weather. Here's a link to the NPS Arctic Network Inventory & Monitoring site. Select Climate to read weather summary reports regarding locations like Howard Pass.

      http://science.nature.nps.gov/im/units/arcn/

      Gary

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  3. With the state being warm this Fall and early winter, is it simply inertia from the tropical air injection? If so, how much does the climate regime in November effect the climate for the next few months? Or is this warmth not related to the remants of the cyclone? And either way, why doesn't the cold winter arctic air come rushing down from the north into the interior? I haven't plugged my car in yet this winter which is mind-blowing.

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    Replies
    1. Good questions, Eric. I would say the tropical airmass associated with the mega-ridge is long gone, but the circulation pattern has not allowed any significant cold to infiltrate central and southern Alaska. As for why - the PDO is now strongly positive, so this is a major factor. The recent post of Nov 27 showed that the positive PDO has a greater effect in December than in Jan or Feb.

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