Thursday, April 26, 2012


Here is a an updated plot of standardized daily temperature departures for Fairbanks thus far this year. Recall that standardized departures are simply a way of scaling the absolute departure from normal to reflect the typical variability for a given time of year Technically, it's the departure from normal divided by the standard deviation. In this case, the daily normal and the standard deviation are taken from the 1981-2010 NCDC normals. This month, the outstanding feature is the nearly unbroken persistence of the warm anomalies rather than any major daily extremes.


  1. Rick,
    I don't think the warm springs in Fairbanks has anything to do with increasing solar radiation like you said in one of your response. Places in the Eastern Canadian territories and Siberia are still below freezing at this time of the year. I'm talking about far inland locations like Yellowknife and Yakutsk, not coastal areas that are cooled by sea ice. I understand that western Alaska along the Bering Sea have delayed spring, being much colder now, due to the effects of sea ice. But how come inland places on the East side of the continent, North America and Asia, warm up less quickly than the counterpart.

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  3. Okay, I assume that you're being hyperbolic when you write that you don't think increasing solar radiation has anything to do with warm springs. It may still be below freezing at the places you mentioned, but it's still far warmer than it was in January.

    At subarctic latitudes, the rapidly increasing solar heating is strongly modulated by albedo. Boreal forest covered areas warm up much faster than tundra areas, even controlling for distance from ocean. Boreal forests are very dark and largely "hide" the snow covered ground, while tundra with snow is blazing white, reflecting back a much higher amount of incoming radiation. Then factor in topography: Interior Alaska has the Brooks Range as a barrier to cold air moving south: the southern Northwest Territories has a lot muskeg to the north.

    The short answer for why the east side of continents are colder in winter than that prevailing wind direction is west to east, so you've got a whole continent as a potential source of cold air. So Spokane, WA, International Falls, MN and Fort Kent, ME are about the same latitude (~47), all protected from marine influences. The average January temperature at Spokane is 29F, +4F at International Falls and +6 at Fort Kent. Same principle works in Europe.

    BTW, Yellowknife is not such a good example, located as it is on the north shore of Great Slave Lake. Compare the temperatures there with say, Fort Smith or Fort Simpson NWT: April temperatures at Yellowknife average almost 5C cooler due to the proximity of the frozen lake.

  4. Thank you for your explanation. Everything makes sense now