I replicated Richard's technique of averaging the departure from normal for a 10-year period (I used 2004-2013) for each station in Alaska. Only stations with at least 80% coverage during the 10 years were used. Stations also had to have 1981-2010 normal daily temperature values published by NCDC. In addition, I smoothed the daily data for each station using a 15-day moving average just as Richard did. Without smoothing, the data really jump around a lot. Figure 1 shows the smoothed (red) versus unsmoothed (blue) 10-year daily temperature departure for Fairbanks.
Figure 1. Average daily temperature departure from the 1981-2010 normal at the Fairbanks International Airport during the 2004-2013 time period. The blue lines are the raw daily averages and the blue line represents a 15-day smoothing of the raw data.
Statewide Departure Lines
Using the example from Figure 1, we can repeat the procedure for all other stations in Alaska with sufficient data. Figure 2 shows the result of all 112 stations in Alaska that had at least 80% data coverage and published normal values from NCDC.
Figure 2. Average daily temperature departure from the 1981-2010 normal for 112 stations in Alaska during the 2004-2013 time period.
Even though Figure 2 clearly shows that the magnitude and direction of the anomaly vectors across the state are remarkably consistent, I thought it would be interesting to see how the trends vary across different regions. Figure 3 shows the average daily departure for all thirteen climate divisions (Bieniek et al.). Figure 4 shows the boundary of the regions. As with Figure 2, there is a remarkable consistency between climate divisions. The only notable exception is the North Slope region during November. Every other station showed strong negative anomalies during the 10-year period but the North Slope region was above normal. I would argue that if the statewide October anomaly is a result of the relativly ice-free Arctic Ocean, which is a reasonable assumption, that effect only lingers across the North Slope into November and the rest of the state no longer feels the influence of the uncovered water.
Figure 3. Average daily temperature departure from the 1981-2010 normal for 13 climate divisions in Alaska during the 2004-2013 time period.
Bieniek et al.). The yellow dots indicate the location of the 112 stations used in the analysis.
*** Update Section ***