RSS and UAH have differing 30 year trends which lie outside my calculated measurement error for the data. Subtraction of the two measures leaves a step located at about 1992. Since they both use the same dataset, the question becomes. Which series is right?
After reading several papers and some short emails to some smart people, I have come to understand the bulk of the trend difference to this single step point in the data which corresponds to the time when satellite NOAA-12 began adding data into the trend.
Below is a graph of the RSS-UAH data where the step is quite visible. The flatness of the slope on either side fo the step is a good indicator that most of the data is in good agreement between the satellite processing algorithms.
The graph below is a plot of the raw data and a filtered difference and the overall trends of the data. You can see the trends are crossed and divergent.
Continue reading “Satellite Temp. Homoginization Using GISS”