Tuesday, December 22, 2009

The Met Office source code

The Met Office has released the source code for analysis of the land surface temperature data.

It consists of two Perl scripts: station_gridder.perl and make_global_average_ts_ascii.perl.

The first one produces the gridded output for the temperature anomalies across the globe by year since 1850. The second takes the output of the first and produces a text file that can shows the global temperature anomaly since 1850.

I've run them both on the same data as my program (and produced an annual average version of the output of my script). Here's a graph that shows their trend (in red) and my trend (in green). Nice, I'm getting essentially the same results as they are.

Note. The output of station_gridder.perl is similar to the current CRUTEM3 file, but not the same. There are small differences.

Here's a graph that compares CRUTEM3 (in green) and the output of station_gridder.perl (in red) on the released data.

And finally a plot of all three data munches: CRUTEM3 (in green), station_gridder.perl (in red) and me (in blue):



OpenID Bishop Hill said...

The first link is to your own site? I'm assuming this is wrong.

9:22 PM  
Blogger John Graham-Cumming said...

@Bishop Hill

Thanks, I've fixed it.

9:27 PM  
OpenID Bishop Hill said...


I'm slightly confused. CRUTEM is prepared by CRU, right? I think this means that we don't have the code for CRU correcting the raw data, but instead the code for producing a land surface average from the adjusted data.

Also, your endpoints seem markedly different from CRU or the Met Office.

9:31 PM  
Blogger John Graham-Cumming said...

@Bishop Hill

You need to read my next post which is coming soon. I don't think this is the source code actually used to generate CRUTEM3. Looks to me like they wrote it specially for this release and it appears to contain a smallish bug to do with the use of suspect data.

9:34 PM  
Blogger steven said...

Of course they didnt release the code to do the adjustments, corrections, etc etc. They whipped up something so they could say they released "the code"
and "the data"

More obsfucation. Don't they know we won't go away.

Keep up the good work John

5:59 PM  

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