Tropospheric Amplification Using GISS
Posted by Jeff Id on January 31, 2009
This is a continuation of my previous post on temperature amplification.
Where I used a frequency sorting method to plot the amplification factor against time. The following graph was a result of that calculation as shown in the previous post. I put it here for comparison.
The next plot is exactly the same as above, using the GISS data.
Note the difference in Y axis, and the extension of the amplification into the negative Y axis. Another thing I see is that the GISS amplificatoin of 1.2 for the global signal looks pretty good while the tropcial amplification extends as high as 1.5. In the GISS version the 17 year trend even extends into the negative for the tropical UAHTMT curve. I plotted the negative point curves as generated in R and the graphs of the two lines look like they could be negative.
I did a quick arma check on the data with trend and found the Hadcrut data has an AR 1 value of 0.87 vs AR1 of 0.73 for GISS. I think this indicates Hadcrut employs an algorithm which generates an increased time dependence in the data. The filtering would make it less useful for this type of analysis since it suppresses the high frequency trends.
It makes me wonder what would happen if we balanced the AR coefficients between satellite and ground and redid the analysis. Even if my frequency weighting of my filter was different, we should get closer to the actual result.