03 December 2009

Corrigendum to Klotzbach et al. 2009: Conclusions Unchanged

For those who followed the blog kerfuffle over Klotzbach et al. (PDF), a corrigendum has been submitted in response to comments that we received from Gavin Schmidt, James Annan, Phil Jones and Ben Santer. My father has posted up the corrigendum in full at his site, which corrects several referencing mistakes. We regret the errors. We also recalculate a tropospheric amplification factor based on comments from Gavin Schmidt (and what we report is consistent with that reported by Ross McKitrick) and perform a sensitivity test at the request of Phil Jones. Both calculations show our paper's analysis and conclusion to be robust. Consequently, I do want to emphasize the bottom line of the corrigendum:
. . . no changes are needed in our paper’s conclusions.
And if you are interested, below are those conclusions from Klotzbach et al., which seem so utterly noncontroversial that they should makes one wonder why the orchestrated attack took place on our paper. I do have my own theories.
We find that there have, in general, been larger linear trends in surface temperature data sets such as the NCDC and HadCRUTv3 surface data sets when compared with the UAH and RSS lower-tropospheric data sets, especially over land areas. This variation in trends is also confirmed by the larger temperature anomalies that have been reported for near surface air temperatures [e.g., Zorita et al., 2008; Chase et al., 2006, 2008; Connolley, 2008]. The differences between surface and satellite data sets tend to be largest over land areas, indicating that there may still be some contamination because of various aspects of land surface change, atmospheric aerosols and the tendency of shallow boundary layers to warm at a greater rate [Esau, 2008; Christy et al., 2009]. Trends in minimum temperatures in northern polar areas are statistically significantly greater than the trends in maximum temperatures over northern polar areas during the boreal winter months.

We conclude that the fact that trends in thermometer estimated surface warming over land areas have been larger than trends in the lower troposphere estimated from satellites and radiosondes is most parsimoniously explained by the first possible explanation offered by Santer et al. [2005]. Specifically, the characteristics of the divergence across the data sets are strongly suggestive that it is an artifact resulting from the data quality of the surface, satellite and/or radiosonde observations. These findings indicate that the reconciliation of differences between surface and satellite data sets [Karl et al., 2006] has not yet occurred, and we have offered a suggested reason for the continuing lack of reconciliation.

No paper in the literature is the last word on anything, so we welcome and look forward to a further discussion of the paper in the peer reviewed literature. We hope that those scientists who have taken such strong exception to the paper in the blogosphere will follow up their strong public criticisms with formal comments in the literature.