The 5 global land-ocean temperature anomaly (LOTA) series use different baseline periods, making direct comparisons between the series more difficult than it would be if each series had the same baseline period.
This post shows how to convert the 5 major LOTA series to a common baseline. Links to on-line source data file and RClimate script are provided. Here is long term LOTA trends using a 133 month moving average and 1979-2008 baseline.
Anomaly Series Baselines
Temperature anomaly series are developed to show differences between the observed values and the baseline period mean. Here is a list of the 5 series and their baseline periods.
This plot shows the GISS LOTA series for the GISS baseline period of 1951-1980 and a 2nd baseline period, 1979-1999.
Click to enlargeTo convert the 1951-1980 GISS series to the 1979-1999 baseline period, I simply calculated the GISS series mean for the 1979-1999 period (0.236) and subtracted this offset from each original GISS value. The 2 series have the exact same shape, they are simply offset by 0.236.
Pretty simple! Readers who would like to read more about creating common LOTA baselines can review these posts:
Common Baseline Trend Chart
Here is a plot of the 5 major monthly LOTA series all converted to a common baseline, 1979-2008.
Compare 2 Series
The 5 LOTA chart is very busy, showing monthly values for the 5 series. I have developed RClimate script to let me compare just 2 series as a trend chart or an XY scatter chart. Let’s compare NOAA and RSS series.
RClimate Script and Data File Links
Here are the links to the RClimate script and LOTA common baseline file.