Checking the Alaska Temperature Record

Dr. Richard Keen of the Department of Atmospheric and Oceanic Sciences of the University of Colorado - Boulder has looked into the temperature records of NOAA's NCDC for central Alaska.  There are 9 stations there with long-term temperature records, which he has used to set up a regional mean temperature record from 1900 to 2004.  The raw temperature results he gets are shown in the plot below:

The temperatures of Alaska are heavily influenced by the Pacific Decadal Oscillation (PDO).  The same raw temperature data is shown with the average temperature over the period of the PDO for each PDO period.  The periods plotted cover four alternating PDOs, starting with a cold PDO and ending with a warm PDO.  This guarantees a general upward slope in temperature, just as starting with a warm PDO and ending with a cold PDO will produce a negative temperature slope.

If you are wondering, there are about 23 years in the first cold PDO and 23 years in the first warm PDO.  Then the second cold PDO covers about 29 years, as does the second warm PDO.  Given these starting and ending points, the upward slope of the average linear trend line in the first figure is 0.69 C/century in the raw temperature data for central Alaska.  Now, let's examine the ever-trusty data from the NOAA GHCN adjusted temperature data set for the same region.

Our ever-reliable government NOAA NCDC has again adjusted the raw temperature record to produce an upward slope to the temperature data in support of a global warming catastrophe.  This slope indicates a temperature increase of a whopping 2.83 C/century!!!!  This is more than a 2 C per century higher rate of change than is found in the raw data!

Plotting Keen's calculated raw temperature data against that of the GHCN after averaging the years within a 10-year period to produce data directly comparable to the data as used in the UN IPCC AR4 report of 2007, one can compare the Keen raw temperature data in blue with the IPCC AR4 adjusted data in black in the figure below:

The early year adjusted data used in the UN IPCC AR4 report of 2007 has been adjusted downward and the data of the last couple of decades has been adjusted upward relative to the raw data reconstructed by Keen.  The net difference across the century is about 1 C, which is the amount of the global warming claimed by the UN IPCC AR4 report generally.  But, once again, there is no known scientific justification for the adjustments to the raw temperature data which have been made by the NOAA NCDC and used by the UN IPCC AR4 report.

What else could be going on here but an attempt to produce a man-made global warming catastrophe justifying drastic government action to control our individual and business use of fossil fuels?