The National Climate Data Center (NCDC)
WANTS
Urban Heat Islands in the USHCN record
Many climate researchers are familiar with the claim by climate scientists that Urban Heat Island Effect does not
contaminate the surface temperature record. This, they say, gives scientists the ability to detect a greenhouse signal in
the temperature record. On NCDC’s webpage, a description of how Urbanization is “accounted for “ in the
new USHCN version 2 data set, is clearly stated:
“In the original HCN, the regression-based approach of Karl et al. (1988) was employed to account for
urban heat islands. In contrast, no specific urban correction is applied in HCN version 2 because the change-point detection
algorithm effectively accounts for any "local" trend at any individual station. In other words, the impact of urbanization
and other changes in land use is likely small in HCN version 2.”
http://www.ncdc.noaa.gov/oa/climate/research/ushcn/
Fast forward to January 2006, as recorded by the American Meteorological Society,
Claude Williams of the NCDC presents how urbanization effects are really "accounted for" in USHCN version 2:
“Retain the low frequency temperature variations like the Urban Heat Island”
“And that’s not necessarily a bad thing,” he says.
At the end of his presentation he proclaims that one of the problems remaining in the USHCN version 2 is that it is
still “inadvertently removing some low frequency variation” (UHI).
Don’t take our word for it, hear and see for yourself:
Go to:
http://ams.confex.com/ams/Annual2006/techprogram/paper_100746.htm
then click the “recorded presentation” link.
