What exactly is meant by “corrected” MXD, you ask? Outstanding question — and the answer appears amorphous from program to program. Indeed, while some employ one or two of the aforementioned “corrections,” others throw everything but the kitchen sink at the raw data prior to output.
For instance, in subfolder “osborn-tree6\mann\oldprog” there’s a program (Calibrate_mxd.pro) that calibrates the MXD data against available local instrumental summer (growing season) temperatures between 1911-1990, then merges that data into a new file. That file is then digested and further modified by another program (Pl_calibmxd1.pro) which creates calibration statistics for the MXD against the stored temperature and “estimates” (infills) figures where such temperature readings were not available. The file created by that program is modified once again by Pl_Decline.pro, which “corrects it” – as described by the author — by “identifying and “artificially” removing “the decline.”
Thursday, November 26, 2009
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7 comments:
In 2 other programs, briffa_Sep98_d.pro and briffa_Sep98_e.pro, the “correction” is bolder by far. The programmer (Keith Briffa?) entitled the “adjustment” routine “Apply a VERY ARTIFICAL correction for decline!!” And he/she wasn’t kidding. Now, IDL is not a native language of mine, but its syntax is similar enough to others I’m familiar with, so please bear with me while I get a tad techie on you.
Here’s the “fudge factor” (notice the brash SOB actually called it that in his REM statement):
yrloc=[1400,findgen(19)*5.+1904]
valadj=[0.,0.,0.,0.,0.,-0.1,-0.25,-0.3,0.,-0.1,0.3,0.8,1.2,1.7,2.5,2.6,2.6,2.6,2.6,2.6]*0.75 ; fudge factor
These 2 lines of code establish a 20 element array (yrloc) comprised of the year 1400 (base year but not sure why needed here) and 19 years between 1904 and 1994 in half-decade increments. Then the corresponding “fudge factor” (from the valadj matrix) is applied to each interval. As you can see, not only are temperatures biased to the upside later in the century (though certainly prior to 1960) but a few mid-century intervals are being biased slightly lower.
Ain't pinko logic a beaut?
Maybe they were just testing their code, Tecs!
Pretty stoopid code. Does he simply add the valadj vector to the data? E.g., add -0.3*0.75 to old temps and +2.6*0.75 to new ones. I mean, duhhh -- these guys get zillions of dollars in grants for something as retarded as that?
I could do that kind of thing for zillions in grants. Where do I sign up?
Oh, now looking at the subsnippet, I get the idea. There's no reason to fucking test code this way. Like you say (and they said) they're just adding in hard-coded goddam numbers, the validj var.
But maybe validj came from something?
What I read was that their code has instructions to ignore errors (like Quiet[] in Mathca,, but you don't know much of that, do you?).
That's pretty serious shit. You can't even tell if the code works!
I still am not sure enough of what the code's doing to call anyone a brash SOB. Briffa or whoever still could've been testing how dicking around with data affected the output.
Or maybe he was playing with himself. Whatever. Bottom line is, this is not the sort of thing you stop the world economy cold in its tracks, so as to please AlGore & Co.
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