We are heading into the time of year when sub zero temperatures occur somewhere in Alaska every day. In 2013 the first occurrence of a subzero day in the databases that NCDC maintains was on October 10th. A couple of stations nearly reached zero the other day as Richard noted but it doesn't appear to have happened yet in Alaska. The following chart shows the statewide average high and low temperature (red colums) and the daily extremes (gray shaded area) between January 1, 2012, and September 24, 2013. It appears that June 18th was the warmest day in Alaska in 2013.
Note: You can zoom into the chart to see much shorter time periods. Click the Reset Zoom button to go back to the original view.
Speaking of zero temps, the potential effects and trends of the PDO on Alaskan temps have been discussed. Here's another perspective from a salmon's point of view. They occupy the north pacific gyre influenced by the PDO:
ReplyDeletehttp://www.nwfsc.noaa.gov/research/divisions/fe/estuarine/oeip/ca-pdo.cfm
Note that as NW US salmon prosper in a cold PDO, Alaskan stocks suffer. Studies are undergoing to determine the cause.
Gary
The Columbia River saw the larget run of Chinooks in 75 years (http://goo.gl/RwbdZv). Good for them.
DeleteTwo thoughts in a row and a question for this Blog. What's the inferred effect of cloud cover on temperature for the above period?
ReplyDeleteDuring 2013 was cloud cover associated with abnormal temps (both below and above normal?), or was it more likely associated with upper air flow patterns and systems?
Not a work assignment, just food for thought brought upon by a hypothesis from a recently read archaeological paper:
http://www.seas.harvard.edu/climate/seminars/pdfs/Guthrie_2001.pdf
Gary
I would guess that it is primarily due to synoptic-scale patterns and not so much cloud cover. The ESRL monthly composites show that 2013 had more northerly winds in the mid levels over the NE half of the state in 2013 compared to 2012 and therefore cooler temperatures. Rick would be a better source on this though.
DeleteIs it the chicken or the egg? Seems the lack of cloud cover (Ok, I'm guessing here, but still?) was associated with both a prolonged Winter/Spring (via radiational and advective cooling), and a warm, sunny, and comparatively dry summer until the end when we finally caught up with normal seasonal precip.
ReplyDeleteMaybe Rick will ring my chimes and bring me back to reality.
Gary
Gary,
DeleteThe Guthrie paper you linked to is extremely interesting. I like the idea that cloud cover in and of itself is a profound driver of climate variations, and I can't help but think of the Svensmark cosmic ray hypothesis. Cloud cover on a synoptic time/spatial scale obviously brings first-order effects to weather variations, but as you say it seems difficult to separate cloud effects from other highly correlated variables.
Richard
I took his Comparative Vertebrate Anatomy class in 1967...and still recall Dr. Guthrie and the excellence of his instruction. His interest in the linked paper was clearly focused upon the climatic conditions that may have led to floral and faunal changes in Beringia after the last cold spell 11-12K years ago.
DeleteEarlier I've mentioned solar input, as measured via a specific meter, or solar panel, as a driver of both weather and climate. Some have linked the PDO and Solar Cycles. And as you note, other factors like albedo, moisture, Skew-T values, wind at various levels, on and on likely all contribute.
Thanks for the new hypothesis. I'll crawl around in that tomorrow over coffee:
https://dl.dropboxusercontent.com/u/51188502/PLA22068.pdf
http://www.sott.net/article/265873-Svensmarks-cosmic-ray-theory-of-clouds-and-global-warming-looks-to-be-confirmed
Gary
Gary, perhaps I shouldn't "go there" but I would steer clear of article written by, or promoted by, Anthony Watts. He is decidedly one-sided in his views and because of that one should always assume that he intentionally omits important information.
DeleteDon't worry Brian, I take all non-peer reviewed personal opinion Gray Lit as strictly entertainment value. That's not to say it's without value, however. Opinions are like...etc. And yes, I've crossed Watts' Up? before.
DeleteWe also avoid speculative discussion regarding Global Anything as a matter of policy at home and elsewhere. It's one thing to ask questions, yet another to provide unsubstantiated answers.
Time for coffee and some reading.
Gary