NASA Data

NASA uses a process they call “homogenization” to calculate the values that they call global temperature anomalies and they publish those numbers in their Land Ocean Temperature Index (LOTI) each month. These values which are hundredth of a degree Celsius are deviations from a base they set as 14.0 degrees Celsius, which then becomes zero on their charts. This base represents, according to them, the global temperature average from 1951 to 1980 and you can see that the plots in the chart here for those years are very close to zero on the y axis.

The chart below contains 8 plots broken into two sets, one set of four 2011 and earlier (brown and orange) and the other set of four 2012 and later (blue and green). This chart was constructed after observing major shifts in the numbers sometime in early in 2012. Clearly there is a major difference between the two sets of plots which should just not be there; red ovals on the chart.

NASA publishes the LOTI table each month and it contains anomalies by month from January 1880 to the present month and that represents 1599 values as of March 2014. Because the values were placed in a column in a spreadsheet for analysis beginning in 2006 at some point the shift in numbers became noticeable and a review was made in 2012. Unfortunately most of the old tables were not saved and so the older set 2009-10 though 2011-10 is not complete containing only 4 out of 24 issued monthly tables. However when placed side by side and seeing how the larger set (not all shown) of more recent values were reasonably stable there is no reason to think that the missing months were any different than the sample available. Previous version of these observation were plotted but were not easy to interpret and so a new method was derived in April 2014 and that is what is shown here.

The process that NASA uses to determine the anomaly results in variability in the data table and so to remove that we looked at blocks of ten years which would then contain 120 values for each month in that set and an average was determined. From 2009 to the present the average was determined by using the actually number of values available for each of the monthly tables. That gave us 14 points to plot from 1880 through 2009 for each of the eight monthly NASA releases being reviewed. The Chart has the ten year time blocks on the X axis and the value of the anomaly on the Y axis. The anomalies are in hundredths of a degree so the total range in degrees Celsius on the chart is 1.6 degrees Celsius.

The values of the anomalies from the first set dropped significantly from 1900 to 1940 and again from 2000 to the present and it was not a gradual change but first one way and then the other way, indicating a programming change.

My take on what happened cannot be proved but it would make some sense with the management in place at NASA when the change was made sometime between November 2009 and October 2011. To those reviewing the data, at NASA, it would have been obvious by say 2005 that temperatures had stopped moving up and that was not possible according to the logic used in the anthropogenic climate change belief. The IPCC and their cohorts had stated many times that the science was settled and the debate was over.

If we look at the periods in the brown – orange set that are around 1920 to the present time the movement up appears to be about 100 (-20 to +80) or 1.0 degree Celsius; however the published values were not reflecting what people were seeing in the real world even though they were what should have been seen according to the IPCC reports. So somewhere a decision was make to reprogram the program that did the homogenization and what they did was lower the 1920 period and the present period about the same amount but set to give about the same upward movement in temperature as previously existed prior to the change. In other words they can say there was no change in the increase in global temperature “so what difference does it make.”

The result is that other set, blue – green shows an upward movement of about 95 (-35 to +60) which matches the older set but ends up at a much lower value that is closer to what the real temperature is even though they don’t like that. The difference between the sets is close to .25 degrees Celsius which is not inconsequential.

Whether this was the reason or not the change is major and that puts into question the process used by NASA to determine the global temperature. This process must be reviewed in detail so we can be sure of what is being published.