The latest from our crack scientists is that UHI has huge effects which extend thousands of miles, but they are too small to be adjusted for in the local temperature record.
Those who wonder why large parts of North America seem to be skipping winter have a new answer in addition to climate change: big city life.
A study, published in the journal Nature Climate Change, found that the heat thrown off by major metropolitan areas on America’s east coast caused winter warming across large areas of North America, thousands of miles away from those cities.
Winter warming was detected as far away as the Canadian prairies. In some remote areas, temperature rose by as much as 1 degree C (1.8F) under the influence of big cities, which produced changes in the jet stream and other atmospheric systems, the study found.
Heat from North American cities causing warmer winters, study finds | Environment | guardian.co.uk
So the UHI effect is huge and massively alters the temperature record. At the same time, USHCN makes no correction for it – because it is unimportant.
no specific urban correction is applied in HCN version 2
ftp://ftp.ncdc.noaa.gov/pub/data/ushcn/v2/monthly/menne-etal2009.pdf
USHCN only makes “corrections” which warm the present and cool the past. Corrections which go the other way are politically incorrect(ions)
But TOBS is critical.
And our predecessors routinely rounded up when gathering data.
This article seems to be a mass of contradictions (not surprising from the Grauniad). For example:
“The extra heat generated by big cities was just a fraction of the warming caused by climate change or urbanisation, the researchers said. But the study did help scientists account for additional warming that was not explained by existing climate models.”
Apart from the use of the term “just a fraction”, to mean “much smaller than”, when it doesn’t necessarily mean that, isn’t the heat from cities part of the heat caused by “urbanisation”?
Also, how can this “account for additional warming that was not explained by existing climate models”, when temperatures are actually lower than most of the models? If some, any part of the warming is caused by UHI, then surely that makes the models even less accurate.
Also, how can cities have “a noticeable impact on regional temperatures almost on a continental scale”, yet “barely affect global temperatures”?
I hate it when “a fraction” is used as a description. It could mean one-billionth, or ninety-nine one-hundredths.
Could one be less specific?
Climatologists are normally less “Specific”! 😉
Being more specific is a disqualification for membership in the “CLUB!
Look at the bright this should make the agenda 21. There goal is larger and larger cities.
We have a huge and increasing UHI effect, but 99% of adjustments have a warm bias. Does that make any scientific sense?