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.
==============================================================
Here’s the first page of the article from Wiley publishing:
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Jones voted against UHI before he voted for it, before he voted against it, before he voted for it …
I think that the real aim of this paper (yes, it is political) is to discredit UHI as a consistent, measurable effect. The paper mentions variable wind speed and direction, anti-cyclonic weather patterns (high cells, sinking air and generally clear weather). I have even seen articles that link UHI to the ‘weekend effect’ when cities cool as the inhabitants leave on the weekend.
The next step would be to establish the trend as the best guide for warming.
As for measuring temperature, looking at the problems with max/min and time of reading, my suggestion is to to select max only and pick the sun’s zenith as the reading time in each location. I know that temps rise after this, but mins and late afternoon readings will have thermal earth heat bank signals that muddy the measurement.
The sun’s zenith is a fair standard that can be applied world wide, certainly is simpler than now.
The continent with a large land area, a long and good temperature record with both Tmax and Tmin, a large number of truly rural sites, the majority of the population in a few large cities, good census records, good weather records in general – is Australia.
Just about every objection to methodology I have read in the analysis of other authors can be overcome by a close study of Australia. It is in progress. It will be less prone to assumptions that any I have read. Do not lose faith that a definitive answer is possible.
Places like the surroundings of London, or certain sites in China, will not show much UHI because it had already neared a plateau before the analysis was done. Australia has many, many places where breezes blowing from one population center to another will be untainted.
According to Muller’s video, if Jones is one of the Team he won’t bother reading any longer. Guess that’s a wasted paper (or a hollow threat on Muller’s part). But then we know now he is not seeking the Nobel prize for transparency and honesty in science.
netdr2 says:
April 2, 2011 at 11:44 am
There is a 7 ° F difference between downtown Dallas and the surrounding countryside at about sundown on a clear summer day. I have measured it myself. I have a temperature recording thermometer [bought from this site] and started in downtown Dallas and drove the speed limit out to the country 35 miles away.
————
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?
Hide the incline (UHI)?
I agree with several people who have noted that in order to understand UHI and temperature trends, it is necessary to seperate out maximum from minimum and to examine trends seperately, month by month.
In doing so, I was able to identify the onset of UHI in the temperature record at Observatory Hill, in the heart of Sydney, Australia.
I was also able to connect this onset of UHI with a historic change in the built environment immediately adjacent to the Stsphenson screen and also the impact of the changing prevailing winds on the rate of UHI increase that occur in different seasons of the year.
UHI at Observatory Hill has a trend change impact on measured temperature which steadily increases each year in a linear fashion, most in winter and least in summer, which is also consistent with other comments to this post.
Doug S says:
April 2, 2011 at 2:05 pm
David Y says:
April 2, 2011 at 12:52 pm
….
“I’m skeptical of the accuracy/validity of the current scientific establishment’s explanations of the onset of ice ages. This doesn’t mean I don’t think they may be correct–rather, no scientific argument has been put forth (that I’ve seen) that fully explains it.
….
I’m not a trained scientist David but I find Dr. Svensmark’s hypothesis for Gamma ray cloud seeding to be particularly interesting. I think the long period between ice ages can be simply explained by our solor system orbiting with the galaxy. As we pass through bands of high Gamma ray flux the cloud cover increases and cooling dominates. Moving out of the Gamma ray flux allows warming to occur. It’s simple explanation, I like it.
You guys are not looking very hard.
Here is a description of what triggers the glacial cycles, the Milankovitch cycles which affect the earth’s orbit and axial tilt:
http://www.homepage.montana.edu/~geol445/hyperglac/time1/milankov.htm
Here is a description of the data, and a historical account of the Milankovitch theory of glaciation which shows how the theory was developed and confirmed during the 1960’s and 1970’s.
http://earthguide.ucsd.edu/virtualmuseum/climatechange2/03_1.shtml
wayne says:
April 2, 2011 at 5:11 pm
“@ur momisugly Theo Goodwin
Seems you got my point. You must have a good logical mind to see that, and why.
Phil Jones is already totally misunderstanding UHI itself. It has two causes and two different effects and he can’t seem to see it, once again. I doubt if BEST will either. Of course, they probably never stop to think.”
Thank you. I really cannot understand why Phil Jones is taken seriously in any way whatsoever. He is no scientist. He does not have the instincts of a scientist.
With your description of the area that Jones studied, we should be off on another lark as we were with extinct sloths and such. I guess people just cannot get their minds around UHI. Maybe most everybody lives in the suburbs and avoids the cities. That is certainly true in most American cities.
As a young lad (1950-1960) I lived in Byfleet, near Wisley.
Where we used to ‘taste-test’ corn and apples that grew within walking distance in a semi-rural area is now covered in housing and the M25 motorway. From Google maps, it appears that a lot of that farming has disappeared – how has that changed the local environment?
A lot of that area is also now almost an outer suburb of London with the consequent increase in traffic.
(Almost) glad I now live in Oz but Julia(r) is making me think maybe I’m not in the Lucky Country any more.
AusieDan
Can we have a look-see at your data? Could you send it to AW so he post it here?
AusieDan says:
April 2, 2011 at 8:20 pm
UHI at Observatory Hill has a trend change impact on measured temperature which steadily increases each year in a linear fashion, most in winter and least in summer, which is also consistent with other comments to this post.
Thanks Dan. Australia and Oklahoma are probably very close to the same in growth patterns. In 1890 when temperature records began there were few towns. Even into the ‘50s you could drive around the state and most main streets were but a block long if that, now they tend to be ~25,000 population with some tall buildings WalMart’s parking lots, subdivisions, etc, etc.
Here the rural temperature trends look exactly as you described of Observatory Hill. Most of any upward trend is in the minimums and a tiny bit if any in the maximums. That is classic UHI. In the winter with much less energy within the cold atmosphere any man-made source affects it greatly. Not much in the summers with piping hot air everywhere anyway, what we might be adding is insignificant to temperatures. I’m speaking of towns, not large cities, they even show hikes in summer days.
Still, if those two, minimum and maximum, are ever averaged together, it appears as if all temperatures are going up and most people assume for some reason hotter summer days, not so, exactly the opposite, cold winter nights when warmer parking lots and structures release the heat gained in the day along with the heat pumped into the structures to stay warm. If the station is anywhere near this, and they usually are, you have UHI effect.
See, cities and rural small towns are somewhat different in UHI effect. That seems to be why Tulsa and Oklahoma City trends look so completely different than the 15 or so rural smaller towns sprinkled around. Anyway, that is what I have gathered after looking into it and what seems to explain it.
Dr. Spencer’s study of temperatures-to-population-density about a half a year ago really pegged this effect numerically.
RGates:
“James ibbotson says:
April 2, 2011 at 10:18 am
I’m thinking the entire so called 20th century slight warming is primarily due to UHI.
That’s a start on a running retreat IMHO…
___
Not likely.”
I have to agree with you firstly because I don’t believe this particular paper takes us down that route anyway, but primarily because the climate science community, or some part thereof, have dug a hole so deep for themselves by moving from the science into advocacy (and who knows what that’s done to the science?) that any retreat, or modification of their position, should they be wrong, is nigh on impossible. Moreover the wrath of the political classes will be visited upon them big time. So they have to dig in and hope they’re all dead before the enormity of what they’ve tried to do to becomes apparent.
September 16, 2003 was a Tuesday, so it seems probable that the photo above was taken during the night or early morning hours because the City around St Paul’s and Whitehall/Westminster are cooler than the surrounding and outlying residential areas.
So, dr Jones starts to mention anti-ciclones. Slowly the theory of Polar Highs by late prof. Marcel Leroux begins – in a bit oblique way – emerge. A theory supported by a lot of observations. There are 2 books on AMAZON by prof. Leroux. Good eye opener when atmospheric circulation is considered (and deficiencies of its modelling).
>London’s population is still 500,000 less than 1938
Is that the population of London proper, or of the metropoltan area?
I think the only one that matters is the entire built-up area. I don’t think heat island effects respect city boudaries.
Anticyclones? UHI? so UHI is dependent on wind direction? Downwind is warmer, duh.
Misdirection. The core issue is integration of urban encroachment effects into the “trend”.
Stephen Brown says:
April 2, 2011 at 2:48 pm
“If I could harness that waste heat I’d be able to start seeds germinating in my poly-tunnel and greenhouse in January!”
I think that you would find, Stephen, that to progress from germination you would have to harness some other waste stuff such as sunlight or artificial ultraviolet light. Only Briffa and the tree ring brigade think that plants thrive on temperature alone.
Christopher Hanley says:
April 3, 2011 at 12:15 am
“September 16, 2003 was a Tuesday, so it seems probable that the photo above was taken during the night or early morning hours because the City around St Paul’s and Whitehall/Westminster are cooler than the surrounding and outlying residential areas.”
Not sure about that. I recall instruction from a seasoned glider pilot at High Wycombe that around late afternoon early evening (summer) it is possible to get weak lift of woods and lakes as the surrounding land cools. The exposed ground that was providing all the lift during the day will cool and continue doing so until it is cooler than the woods and lakes. At that point you get the lift of the woods. I have felt this lift and it only lasted about 30 mins, but it was weak. I would say this photo could still be around the middle of the day because 32C is quite warm, especially for September.
I wonder if the city is showing cooler because the tall buildings create sheltered ‘canyons’ particularly as the sun is not overhead at this time of year.
Is it possible the one of the “Fingerprints” used as proof of AGW, the fact that nighttime temperatures have increased more than daytime temperatures, actually be a fingerprint of UHI? I go into details of the logic of this at my website, http://socratesparadox.com/?p=195.
eadler says:
~~~~April 2, 2011 at 8:23 pm
Doug S says:
~~~~April 2, 2011 at 2:05 pm
David Y says:
~~~~April 2, 2011 at 12:52 pm
Milankovitch cycles are given a new twist here:
http://motls.blogspot.com/2010/07/in-defense-of-milankovitch-by-gerard.html
If you search the site (the reference frame) with the term – milankovitch – there are additional results.
re: eadler
Please drop the arrogance.
Finding info on Milankovitch Cycles is easy–it’s all over the place. Additionally, the websites you shared provide a view into the flipping of the climate ‘mode’, especially the departure from the dominant cool mode toward the interglacials. Great.
None of this–and this is where I am frustrated, because the current science doesn’t even fit the rigor my software customers require for business case justification of ROI prior to spending a chunk of dough on enterprise software–document or provide detailed models explaining details of the following:
1. A rate of ice accumulation and description–detailed–of how exactly the ice is accumulating. It’s not enough to simply say “well, less snow melts than freezes”. No sh_t Sherlock. Over what time scale does a continental ice sheet grow? Show me the calculations for ice accumulation, including changes (if any required) for rates of precipitation, rates of melt, etc. Explain the rate of advance.
2. A point of glacial genesis (other than ‘somewhere toward the poles’). If you track the retreat of the Wisconsinian glaciers in N. America, they withdraw to somewhere on/around Baffin Island. So let’s model where the ice accumulation happens. Is all the ice forming in a specific area? If the glaciers were plowing southward, this would indicate huge accumulation of ice/precip in a fairly localized area. Yes, melt & sublimation would be less than accumulation. But let me see someone model this.
3. What is happening with the climate elsewhere? Could this be like New Zealand, where it can be tropical/subtropical at the terminus of the glacier?
By simply pointing to Milankovitch Cycles, you’re taking the easy way out and skipping the details. I call that incomplete science. I know data is limited. So try a theory and support it with math.
DY
When I mentioned that the biggest anomalies have been in the arctic, several readers suggested that camp fires and settlements are responsible for the anomalies in the arctic (e.g., northern Canada and Greenland). Can I then assume that campfires are responsible for the strong decline in arctic sea ice and evidence for melting of tunda across vast tracts of tundra in Alaska, Canada and Siberia? Is UHI responsible for the rather good agreement between surface temperatures and the satellite record? So far, all of the peer reviewed literature seems to say that UHI does not bias the surface record, including at least one publication based on data from Anthony’s surface statiobn analysis. I am looking forward to more journal publications on this topic.
John Trigge says:
April 2, 2011 at 9:43 pm
“As a young lad (1950-1960) I lived in Byfleet, near Wisley.
Where we used to ‘taste-test’ corn and apples that grew within walking distance in a semi-rural area is now covered in housing and the M25 motorway. From Google maps, it appears that a lot of that farming has disappeared – how has that changed the local environment?”
Roger Pielke, Sr., is your man. He has been researching UHI and land-use changes for several years and attributes considerable warming to them. Search on his name for his website.
BillD: “Is UHI responsible for the rather good agreement between surface temperatures and the satellite record?”
I would disagree strongly that there is good agreement. I would suggest that when both satellite systems suggest it is no warmer than 1980, claiming that there is warming going on is misguided.
February 2011
Satellite
UAH : -0.018C
RSS: 0.051 C
Non-Satellite
NOAA/NCDC : .4042C
GISTEMP: .44C
HADCRUT: .267C