Making mistakes

200910261324.jpgby Johnny Jet
Plimer the plagiarist

[Via Deltoid]

Eli Rabett has been investigating Ian Plimer’s claim that climate scientists were coking the books on the CO2 record. Plimer wrote:

The raw data from Mauna Loa is ‘edited’ by an operator who deletes what is considered poor data. Some 82% of the raw data is “edited” leaving just 18% of the raw data measurements for statistical analysis [2902,2903]. With such savage editing of raw data, whatever trend one wants can be shown. [p 416 of Heaven and Earth]

The raw data is an average of 4 samples from hour to hour. In 2004 there were a possible 8784 measurements. Due to instrumental error 1102 samples had no data, 1085 were not used due to up slope winds, 655 had large variability within 1 hour but were used in the official figures and 866 had large hour by hour variability and were not used.[2102] [p 418]

This drew a correction from NOAA’s Pieter Tans:

To illustrate how misleading Plimer is I made a plot of 3 years of all hourly data, with 2004 in the middle because Plimer discussed 2004. … In the plot, “selected” data means that we have used it in constructing the published monthly mean because those hours satisfy the conditions for “background” measurements. The red stripes are extremely close to the published monthly means. … Also plotted in purple-blue are all non-background data. If one constructs monthly means from ALL data, incl. non-background, one obtains the purple-blue stripes. The differences are only slight, with the seasonal cycle becoming a bit larger due to upslope winds, esp. during the summer.

Tans concludes that Plimer is a con man, but the story doesn’t end there. Plimer’s reference 2102 is ftp://ftp.cmdl.noaa.gov/ccg/co2/in-situ/. I analyzed the 2004 Mauna Loa data from there and found there were some minor errors in Plimer’s numbers: In fact, due to instrumental error 1103 samples had no data, 1097 were not used due to up slope winds, 655 had large variability within 1 hour and were not used and 881 had large hour by hour variability and were not used.

[More]

One of the easiest way to tell plagiarism is when mistakes are carried forward by the plagiarist. In fact, some people actually put errors into such things as the Index or other sorts of databases. Then is the error is copied, they know that their database was copied also.
In this case, the error appears to come from a paper that directly refutes the exact point Plimer is trying to make. Awkward.
When people try to accuse researchers of manipulating data, data that others have been able to examine for years, they had better make sure they know what they are doing. There is no grand conspiracy of scientists because if these data had been manipulated to get certain results, other researchers would have gone “Great. Now I can get a paper demonstrating that they did it wrong.” We live for publications and being able to demonstrate where someone else went wrong is a great way to make a career.
The fact that this data has been vetted by others and found to hold up makes Plimer reasoning even more off kilter.

[Listening to: She Said She Said from the album “Revolver [2009 Stereo Remaster]” by The Beatles]