We’re a little late to the rodeo, but you should go see the big news from Anthony Watt and his team at Watts Up With That?
Watt released a new paper that is the culmination of knowledge gleaned from five years of work by many volunteers and contributors to the SurfaceStations project started that he started in 2007.
The USHCN is one of the main metrics used to gauge the temperature changes in the United States. The first wide scale effort to address siting issues, Watts, (2009), a collated photographic survey, showed that approximately 90% of USHCN stations were compromised by encroachment of urbanity in the form of heat sinks and sources, such as concrete, asphalt, air conditioning system heat exchangers, roadways, airport tarmac, and other issues. This finding was backed up by an August 2011 U.S. General Accounting Office investigation and report titled: Climate Monitoring: NOAA Can Improve Management of the U.S. Historical Climatology Network.
Watts et al 2012 has employed a new methodology for station siting, pioneered by Michel Leroy of METEOFrance in 2010, in the paper Leroy 2010, and endorsed by the World Meteorological Organization (WMO) Commission for Instruments and Methods of Observation (CIMO-XV, 2010) Fifteenth session, in September 2010 as a WMO-ISO standard, making it suitable for reevaluating previous studies on the issue of station siting.
The new rating method employed finds that station siting does indeed have a significant effect on temperature trends.
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.
Congratulations to Anthony and his team!