Guest Post By Walter Dnes:
Image Credit and a special thanks to Josh
With GISS incorporating NOAA/NCEI “Pause-Buster” adjustments for their monthly anomalies as of June 2015 data, our friend Daft made another appearance. Also, I noticed that my temperature-tracking spreadsheet at home, and on Google Docs both needed to have their Y-axes extended, because the highest anomaly in the data (i.e., January 2007) was raised. This prodded me to check the progress of the GISS anomalies over time.
I only started downloading GISS data in 2008, plus I picked up a few older uploads back to 2005 from the “Wayback Machine”. This accounts for the limits on my comparisons. GISS data downloaded from here is given in hundredths of a Celsius degree; e.g. 15 ==> 0.15 C degree. This allows the numbers to be integers.
For those of you who wish to do their own analyses, the downloads are available in a zip file saved to WUWT here. The files are in 2 formats. The files named gissYYYYMM.txt (“YYYY” = year and “MM” = month) are in the original tabular download format, with 12 months of data per row. This is human-readable, but very difficult to import into a spreadsheet. For each such file, I’ve generated a file named gYYYYMM.txt, which is suitable for importing into a spreadsheet. The generated files contain date in decimal format, a comma, and the anomaly. As noted above, the anomaly is an integer equal to 100 times the actual anomaly. All files are in DOS/Windows format. Linux/Unix/BSD users, please run dos2unix on the files for use in a posix environment. Note that this data set uses the corrected data issued by GISS on July 19th. For details see the “News” section on GISS’s website where they acknowledge Nick Stokes for noticing a recent bug in the GISS data.
First, let’s look at the difference between GISS anomaly data from May 2015 and June 2015.
There were additional adjustments going back to 2005. Here is the graph of combined adjustments between August 2005 and June 2015.
As mentioned earlier, I had to extend the Y-axis in my graph, because the temperatures were adjusted upward. A quick analysis showed that the highest anomaly for almost every download (starting from 2007, obviously) was for the January 2007 anomaly. The only exception was the September 2012 download. It showed the March 2002 anomaly 1/100th of a Celsius degree higher than the January 2007 anomaly. The following graph shows the inexorable upward march of the March 2002 and January 2007 anomalies. Seven years ago in mid-2008, GISS told us that the January 2007 anomaly was +0.85. Today, they’re telling us that the January 2007 anomaly was +0.97. I wonder what they’ll be telling us seven years from now.
This encouraged me to look at the lowest anomalies for each download. From my earliest available download, August 2005, through May 2015 the lowest anomaly was always for the month of January 1893. But in the June 2015 download, the January 1893 anomaly jumped up +0.17 of a Celsius degree, giving up the lowest anomaly ranking to December 1916. Ten years ago, back in mid-2005, GISS was telling us that December 1916 was -0.56. Today they’re saying December 1916 was -0.77. Again, what will it be ten years from now?