Since BEST claims they will work to take UHI into consideration, it seems worthwhile to highlight this new paper. Guess who’s a co-author? Phil Jones of UEA’s CRU.
From Dr. Roger Pielke Sr.:
New Paper “Decadal Variations In The Nocturnal Heat Island Of London” By Wilby Et Al 2011
There is a new paper that adds significantly to our understanding of the urban heat island, and thus its role on long-term surface temperature records. The new paper is
Robert L. Wilby,Philip D. Jones and David H. Lister: Decadal Variations In The Nocturnal Heat Island Of London. Weather March 2011. DOI: 10.1002/wea.679
The abstract reads
“Our review of the long-term behaviour of London’s UHI provides a salutary reminder that the appearance and disappearance of trends in environmental data can depend very much on the segment of data analysed. Nonetheless, we can confirm – using both daily and monthly temperature records – that the summer nUHI did intensify between the late 1950s/early 1960s and the 1980s. This period coincided with an abrupt increase in the frequency of summer anticyclonic weather. There is also evidence of a slight rise in the annual number of intense heat-island events that can be linked to more persistent anticylonic weather systems at that time. A weak decline in summer nUHI since the 1980s coincides with a rise in the frequency of cyclonic weather. Since 1931, the summer nUHI has risen slightly, but not significantly. The overall annual mean nUHI does, however, show a weak but significant (p<0.05) rise when the monthly SJP record is compared to that of WIS.”
Their concluding remarks read
Our review of the long-term behaviour of London’s UHI provides a salutary reminder that the appearance and disappearance of trends in environmental data can depend very much on the segment of data analysed.
Nonetheless, we can confirm – using both daily and monthly temperature records – that the summer nUHI did intensify between the late 1950s/early 1960s and the 1980s. This period coincided with an abrupt increase in the frequency of summer anticyclonic weather. There is also evidence of a slight rise in the annual number of intense heat-island events that can be linked to more persistent anticylonic weather systems at that time. A weak decline in summer nUHI since the 1980s coincides with a rise in the frequency of cyclonic weather. Since 1931, the summer nUHI has risen slightly, but not significantly. The overall annual mean nUHI does, however, show a weak but significant (p<0.05) rise when the monthly SJP record is compared to that of WIS.
Over the 50-year daily record, less than half of the variance in the summer-mean nUHI signal is explained by synoptic weather patterns. This could be due to a number of factors. The weather types describe conditions across the British Isles generally, rather than for southeast England specifically. The conditions experienced within a given weather class are known to vary from day to day. There have also been marked changes in regional air quality in the wake of the notorious winter ‘smogs’ of the 1950s and the summer stubble burning
of the 1970s and 1980s. Other time-dependent factors (such as artificial heat sources, building albedo, thermal mass, sky-view factors, surface roughness, and vegetated area) may be locally important (McGregor et al., 2006). Furthermore, censuses show that the population of Greater London peaked in 1939 then fell until 1991 and has since risen again.”
This paper is an important new addition to the literature on multi-decadal surface temperature trends.
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Here’s the first page of the article from Wiley publishing:
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LazyTeenager says: “…And you did this in a car that had been standing in the sun all day AND at the time of day when the temperature is falling fast. I am the only person who sees something wrong with this?”
Yes. You are ignoring sensor placement relative to the vehicle and the fact that the vehicle was moving at speed limit. The car was moving fast enough that your other worries are of no consequence.
BillD says:
April 3, 2011 at 3:14 pm
BillD, I suggest you look up the definition of the logical fallacy known as a red herring…which is what your above discussion is. We aren’t arguing the sea ice and tundra melt here, and there are possibilities that these could happen without global warming, much less AGW or CAGW.
I was unaware that the land-based temperature records agreed so well for the Arctic (I’d also argue that the more important factor is the temp at both poles, considering that both poles were the prediction of the climate models which you’re pointing to, but we’ll ignore that for now). Do you have data to back up the claim of good agreement in the Arctic?…I’d be curious to see it if you do. No, overall agreement for a global anomaly is not the same…and considering how different GISS has been this past decade relative to the other land-based records and the satellites, I don’t even know if your statement holds for the globe either.
How many serious peer-reviewed inquiries into the subject have been performed using the complete data set? Data sets with only a fraction of the sites that have not been quality controlled don’t count.
-Scott
BillyBob says:
April 3, 2011 at 8:03 pm
While I agree with you that the agreement is not as well as is often hand waved, are those anomalies using the same temporal base period? If not, that makes it an apples vs oranges comparison and therefore invalid. Once on the same base period, we should actually be discussing Arctic temps (or temps at both poles instead), because that’s what is under discussion.
-Scott
Just look at the ‘speckle’ character of that photo.
Think about how poorly the air is integrating all those temperature variations.
So you can make a ‘trend’ by having your station in a ‘cool speckle’ in 1950-1980, then moving it to a ‘warm speckle’ just a few meters over…
It’s not just the overall UHI that matters, it is that you measure but a single point in that mess, and the point moves over time, as does some of the mess…
E.M.Smith says:
April 4, 2011 at 12:08 pm
“Just look at the ‘speckle’ character of that photo.”
Good observation. We know that temperature series are brown noise in the temporal dimension, so they’re fractal; probably the same applies in the spatial dimensions.
Scoitt: “we should actually be discussing Arctic temps (or temps at both poles instead), because that’s what is under discussion.”
There are very few arctic weather stations so most data is extrapolated (fabricated).
HADCRU is less out of whack because they fabricate less data than GISTEMP.
BillyBob says:
April 5, 2011 at 7:45 am
Right, so can we compare the satellite results at more extreme latitudes with the GISS (or HadCRUT) ones? I know the satellites don’t get the poles, but it still might be a useful comparison.
-Scott