by Vincent Gray

JULY 30th 2012

Image: WUWT

Anthony Watts, Evan Jones, Stephen McIntyre and John R Christy have published in draft form a new study on US weather stations at

They apply a new methodology which makes allowances for every possible interfering factor such as proximity to heat sources or concrete,  asphalt, runways, tarmac and buildings, area weighted and distance weighted, and quality of equipment and maitenance. They apply these to thirty years of US temperature records from 1979 to 2008.

Using the new Leroy 2010 classification system on the older siting metadata used by Fall et al. (2011), Menne et al. (2010), and Muller et al. (2012), yields dramatically different results.

Using Leroy 2010 methods, the Watts et al 2012 paper, which studies several aspects of USHCN siting issues and data adjustments, concludes that:
These factors, combined with station siting issues, have led to a spurious doubling of U.S. mean temperature trends in the 30 year data period covered by the study from 1979 – 2008.
Other findings include, but are not limited to:

  • Statistically significant differences between compliant and non-compliant stations exist, as well as urban and rural stations.
  • Poorly sited station trends are adjusted sharply upward, and well sited stations are adjusted upward to match the already-adjusted poor stations.
  • Well sited rural stations show a warming nearly three times greater after NOAA adjustment is applied.
  • Urban sites warm more rapidly than semi-urban sites, which in turn warm more rapidly than rural sites.
  • The raw data Tmean trend for well sited stations is 0.15°C per decade lower than adjusted Tmean trend for poorly sited stations.
  • Airport USHCN stations show a significant differences in trends than other USHCN stations, and due to equipment issues and other problems, may not be representative stations for monitoring climate.

Also see a lecture that was presented at the recent Heartland Sceptyics conference

Professor Illaniaov shows that the current method  of assessing Russian weather stations exaggerates the few (only 4) stations with records before 1859 and impose the urban heating from these stations on the whole set, however large. Since Russia has 11.5% of the total land area of the has a large influence on global figures, which are themselves affected by a similar error..

Vincent Gray
Wellington 6035

"It's not what you don't know that fools you. It's what you do know that ain't so." ~Josh Billings

Sustainability is impossible. There are only two directions; forward and backward.