Apr 14 2008
Comparable Global Climate Metrics
Since some people insist on comparing the monthly values of the GISS, Hadley, RSS, and UAH global tropospheric temperature anomalies without compensating for their use of different base periods, I’ve created a semi-automated process that does it. All it does is download 4 global temperature metrics mentioned above, remove any data before 1979, and then subtract the mean from each of the 4 time series. This means that they will all use the January 1979 to present as the base period.
Data file of 4 climate metrics
The format of the file has the decimal year in the first column, and the next four columns have the temperature from GISS, HAD, UAH, and RSS. The first row is a string describing each column, and can be ignored.
As a simple exercise, I’ve taken the data and plotted it all in the figure below.
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All 4 show good agreement in long-term trends, with the UAH temperatures being the furthest from the rest. The RSS satellite data has the highest trend value.
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6 Responses to “Comparable Global Climate Metrics”
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Why not just install a brain inside Watts’s head? Wouldn’t that be simpler? Maybe some PT outside at night in the mud would be good for him too. Grind him down hard.
Thanks Atomz. Childish and unproductive comments by phantoms aside, the point here is that it is about public perception.
There’s few outside of the tight circle of climate science or meteorology that would know to do this adjustment or even how to start.
While I may not have a “brain” according to some on this issue, 99% of the general population doesn’t either. And that’s the real problem. If you are putting these numbers out on a website for public consumption, getting them all to a common presentation baseline is the best thing you can do to promote public understanding.
Example - this graphic from GISS is one of the most widely circulated in the world:
http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.gif
Yet GISS doesn’t even bother to present the baseline period on their page for it:
http://data.giss.nasa.gov/gistemp/graphs/
Doubtful then, that the general public would pick up on that. Perhaps that is omission, perhaps it is design, perhaps they just don’t care because people like me are just “stupid” in their mind and aren’t worthy of the effort.
Another commonly referenced resource, Wikipedia, at least mentions it, though they use HadCRUT and don’t explain the base period relevance in the text:
http://en.wikipedia.org/wiki/Global_warming
So when the general public looks at other anomaly graphs, there are bound to be confusions since they none match due to the different baselines GISS, UAH, RSS, and HadCRUT use.
Call me “brainless” if you wish, but as a TV/radio meteorologist, I tend to see things they way my audience, the general public does.
The solution, as I’ve mentioned on my blog and as you’ve demonstrated, is to have them all report on a common adjusted baseline.
No fuss, no mess. Though I doubt GISS would change, we’ll see.
Atmoz, Just a note to clarify the above, since I realize this could be interpreted different than I intended.
“Yet GISS doesn’t even bother to present the baseline period on their page for it:”
I’m referring to the subsection of the page and for that graph itself. While there is a mention of the baseline period on the global maps, above it, there are separators between that and the time series anomaly graph, and it has no implicit reference between the graph and the base period.
It just seems to be good form to always put such references with the graphs, perhaps even embedded in them, since text and graphics often get disconnected during public consumption on the Internet.
For my part, I’m going to start doing that on my own plots of the data.
[...] I posted a file online that made it easy to compare the temperature anomalies from GISS, Hadley, RSS, and UAH. I’ve taken that one-half step further today and took the mean and standard deviation of the [...]
“Childish and unproductive,” a bit like your frequent attacks on Al Gore, hmm, Anthony? Pot, kettle, black.
[...] blog: Setting the various temp databases to a consistent baseline isn’t too tough. See here and here for an up-to-date comparison of four of them. The results are disappointing to denialists [...]