Erratum: A Test of Corrections for Extraneous Signals in Gridded Surface Temperature Data. McKitrick, R. & Michaels, P. J. 26:159–173.
Erratum: A Test of Corrections for Extraneous Signals in Gridded Surface Temperature Data [pdf]Paper  abstract   bibtex   
There was a mistake in the command file used to compute the results in our paper (McKitrick & Michaels 2004). The formula for computing cosine of absolute latitude (COSABLAT) takes the angle in radians, but our data were entered in degrees. We have corrected this and produced new versions of the affected tables. Table 4 below, showing the central results of the paper, displays the original and corrected columns side-by-side for ease of comparison. Tables 5 to 8 are presented in corrected versions only. As is evident in Table 4, except for the impacts on the COSABLAT variable itself, the changes are very small. The principal effect of the correction is a reduced weight on the constant term and an increased weight on the COSABLAT variable itself. Indeed, the correction improves the overall fit and removes the anomalously small cosine-latitude effect. The socioeconomic variables remain significant and the effects carry over from the station data to the gridded data as before. Because the main patterns of results persist across the revised tables, the original discussions as worded in our paper need only minor modification, and our overall conclusion, re-stated here, is unaffected: Overall, the results of this study support the hypothesis that published temperature data are contaminated with nonclimatic influences that add up to a net warming bias, and that efforts should be made to properly quantify these effects. Except as noted below, readers should rely on the original discussion in McKitrick & Michaels (2004), substituting corrected coefficient values as necessary.

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