I’ve reposted this here in entirety with permission from Pierre Gosselin of “No Tricks Zone“, and it is well worth the read. Much of this work was inspired by posts that have appeared on WUWT. Ed Caryl has done a great job pulling various threads of info together. One generally doesn’t think of any Arctic circle outposts as being “urban” but the fact is that islands of humanity, essentially small towns, surround many of these stations. And in the Arctic, you produce a lot of energy (which has to go somewhere) or you die. What I find most interesting is the plot of “isolated” stations versus the Atlantic Meridonial Oscillation (AMO); a clear correlation of the driver for those temperatures.. – Anthony
By guest writer Ed Caryl
Arctic stations near heat sources show warming over the last century. Arctic stations that are isolated from manmade heat sources show no warming. The plots of “isolated stations” and “urban stations” below clearly illustrate the differences.
Stevenson Screen, Verhojansk, Russia
All the GISS temperature anomaly maps show the Arctic warming faster than the rest of the globe, especially northern Alaska and Siberia, but the satellite data shows a different pattern. See the 2 charts for 2009 that follow. The GISS surface map:
Satellite chart:
The baseline period selected for the GISS surface temperature chart is the 1933 to 1963 Atlantic Multi-decadal Oscillation (AMO) warm period. This period more closely matches today’s temperatures than the default 1951 to 1980 cool period that GISS uses. The satellite data uses the average over the satellite period since 1979, the modern warm period.
The satellite data show cooling in central Siberia, similar to the surface anomaly map, and very little warming for most of Alaska. It also shows cooling for the Antarctic Peninsula, where the surface map shows warming. But there is a scattering of hot grid squares across the HISS surface station map for the Arctic. So what is going on?
I selected the stations that correspond to those warm grid squares, as well as other stations in the same latitudes. In this age of everyone carrying a camera posting all photos on the Internet, there is a lot of information available on these stations. For some I could locate the Stevenson screens, for most I’ve found pictures of the surroundings, while others have investigated many of these sites already, and so links to that research are included. I downloaded the raw temperature data from GISS for 24 stations closest to the North Pole, which are all classified as “rural”.
“Urban” Arctic Stations
Contrary to GISS claims, many of these stations are actually not “rural” with respect to their siting quality. Many are at airports associated with sizable towns or research stations with sizable staff and infrastructure. In the Arctic, any town of more than a few families can be a large heat source. In the case of many towns in Russian Siberia, “central heating” takes on a whole new meaning. These towns have a central power plant that provides electricity and steam heat to the whole town. Large pipes, both insulated and un-insulated, carry steam, water, and sewage, up and down the streets to and from each dwelling. These pipes cannot be buried because of the permafrost, so they are elevated, and at street crossings are elevated 4 or 5 meters. The temperature differential between these pipes and the surrounding air can be 140° C in winter, and even more for a pressurized system.
But GISS applies the same Urban Heat Island (UHI) criteria to all stations globally, regardless of the latitude or average temperature. They look at the satellite night brightness and population to judge whether urban or rural. By GISS criteria, all the stations in the high Arctic are rural; there are no corrections for UHI.
But let’s look at each of these “urban” locations. Each name is also a link to the GISS surface temperature raw data.
List of Urban Arctic Stations (see the annex at the end of this post for details on each station)
1. Kotzebue, Ral (66.9 N,162.6 W), Alaska
2. Barrow/W. Pos (71.3 N,156.8 W) Alaska
3. Inuvik (68.3N, 133.5W) Inuvik, Canada
4. Cambridge Bay (69.1 N,105.1 W) Nunavut, Canada
5. Eureka, N.W.T. (80.0 N,85.9 W), Canada
6. Nord Ads (81.6 N,16.7 W Northeast Greenland
7. Svalbard Luft (78.2 N,15.5 E), Norway
8. Isfjord Radio (78.1 N,13.6 E), Norway
9. Gmo Im.E.T.(80.6 N,58.0 E), Russia
10. Olenek (68.5 N,112.4 E), Russia
11. Verhojansk (67.5 N,133.4 E), Russia
12. Cokurdah (70.6 N,147.9 E), Russia
13. Zyrjanka (65.7 N, 150.9 E), Russia
14. Mys Smidta (68.9 N,179.4 W), Russia
15. Mys Uelen (66.2 N,169.8 W), Russia
The following graphic is a temperature chart for 10 of the above stations (5 of the shorter ones were left out to avoid over-crowding). All are warming, some faster than others. Barrow, for which we have the UHI study, is not the fastest warming.
Temperature trends of the “urban” stations.
Isolated Stations
Now let us look at the isolated stations, which are located at similar latitudes like the above “urban” stations. One important thing to note about these isolated stations – there is limited electrical power, and so incandescent light bulbs in the Stevenson screens is unlikely. Detailed descriptions of these stations are listed in the annex at the end of this report.
16. Alert,N.W.T.(82.5 N,62.3 W), Canada
17. Resolute,N.W. (74.7 N,95.0 W), Canada
18. Jan Mayen (70.9 N,8.7 W), Canada
19. Gmo Im.E. K. F (77.7 N, 104.3 E), Tamyr Peninsula, Russia
20. Ostrov Dikson (73.5 N,80.4 E, Russia
21. Ostrov Kotel’ (76.0 N,137.9 E), Russia
22. Mys Salaurova (73.2 N,143.2 E), Russia
23. Ostrov Chetyr (70.6 N,162.5 E), Russia
24. Ostrov Vrange (71.0 N,178.5 W) , Russia
Now here is the chart of the temperatures of these isolated stations, not subjected to manmade structures or heat sources.
Isolated Stations
Note that most of the trends are flat or decreasing. Only Resolute and Ostrov Vrange are increasing slightly. Both of those might be slightly influenced by UHI. The longest records clearly show warming in the late 1930’s and 40’s, and cooling in the 1960’s, and none show a hockey stick. The GISS data for Alert ends in 1991, though the weather station is still there, and still reporting. Data for Mys Salaurova and Ostrov Chetyr also ends at about that time, probably due to the fall of the Soviet Union.
Here is an average of all the isolated stations:
Isolated Stations – Average
Note that the peak-to-peak trend is nearly zero. The linear trend is about 0.4°C/century, but the R2 value (the statistical significance for the trend) is very low, 0.023.
Here is a plot of the AMO versus the average temperature of the isolated stations.
The temperature as measured at stations isolated from any UHI is simply tracking the AMO.
Looks like an awfully good fit. There is very little, if any, global warming. We need to wait until the bottom of the next AMO cycle to get a decent reading of global temperature change. That will be in about 2050 if the AMO cycles as it has since 1850.
———————————————————————————————-
Annex – station descriptions
The “urban” stations, nos. 1-15
1. Kotzebue, Ral (66.9 N,162.6 W),
2. Barrow/W. Pos (71.3 N,156.8 W)
These towns are of similar size, and are growing at the same rate. In 1940, both towns had a population of 400. In 1980 both had just over 2000 population, and now they both have over 3000 people. Both have airports of sufficient size to handle multi-engine turboprop and small jet aircraft, and both are served daily by regional airlines. Kotzebue is on a peninsula and the airport is across the middle of the peninsula, somewhat restricting the growth of the town. Barrow has somewhat the same problem due to a series of small ponds around the town and the airport. Barrow was studied for UHI effects in 2003. That paper was in the International Journal of Climatology here. That paper describes the UHI average temperature increase in winter as 2.2°C compared to the surrounding hinterland. GISS data indicates that Barrow average temperature has increased over the years as population has increased. (See below, or click on link above.)
Barrow, AK
Source: http://en.wikipedia.org/wiki/File:BRW-g.jpg
Source: http://en.wikipedia.org/wiki/File:OTZ-g.jpg
The Barrow NWS station (Stevenson Screen) is here. On the airport picture, it is at the base of the rotating beacon tower. Kotzebue NWS station is not visible in published pictures.
Inuvik is a relatively new town, begun in 1954. The population as of 2006 has grown to about 3500 people. Because it is a “planned” community in the arctic, built on permafrost, the water and sewage infrastructure is above ground in heated and insulated “utilidors”, like the heating systems in Siberia. The weather station, from weather reports, Google Earth and Google Street View, appears to be at the airport, in a compound just north of the entrance.
4. Cambridge Bay (69.1 N,105.1 W), Cambridge Bay, Nunavut, Canada
There is a Wikipedia picture of Cambridge Bay here. The population has grown from just a few people in the 1940’s to about 1500 today. It also has an airport with daily regional airline service.
5. Eureka, N.W.T. (80.0 N,85.9 W), Eureka, N. W. T., Canada
There are the only four stations at or north of 80° latitude, Eureka, Alert, Nord and Krenkle (Gmo. I.M.ET). Only Eureka has an unbroken temperature record to the present date, and it begins in 1947. The population at Eureka has
Eureka station
never been high. In winter it has always been 4 or 5 men. In summer, the population increases to as high as 20. The station infrastructure though, has expanded through the years. Each year, some of those 20 workers add or expand buildings. In the beginning, it was one or two buildings, with water and sewage handled in tanks and barrels internal to the buildings. The Stevenson screen was originally placed where the blue New Main Complex building is now. When that was built, the Meteorological instruments were moved to the current location. Over time, the water supply, plumbing, and sewage treatment was upgraded and the outfall pipe installed. It, of course, must be heated to facilitate flow to the sewage lagoon. All the water pipes exposed to the outdoors must be heated to prevent freezing.
Image from a recent article by Anthony Watts on WUWT here.
6. Nord Ads (81.6 N,16.7 W, Northeast Greenland
Nord Station
Nord is the furthest north inhabited place on earth, on the Northeast coast of Greenland. It was built in the period from 1952 to 1956 as an emergency airfield for aircraft operating out of Thule. Access is impossible by sea because the sea ice never moves away from the coast there. Legend has it that “Blowtorch” Murphy, a mythic arctic construction worker, scraped the first runway, using a parachute dropped caterpillar tractor after he himself parachuted onto the site. His nickname came from his habit of wearing a lit blowtorch hanging from his waistband on a wire; a lit blowtorch being somewhat useful when working outside when it’s 40° below zero.
There are about 40 buildings at Nord. Not all of them are continuously heated, but those near the Stevenson Screen are. The winter population is 5 or 6 men. More pictures here.
7. Svalbard Luft (78.2 N,15.5 E)
8. Isfjord Radio (78.1 N,13.6 E)
These two stations are only 47 kilometers apart. But data for both is fragmentary for 1976 and 1977, and there is no overlap. Svalbard Luft (airport) has been discussed on WUWT here and here, so I won’t cover it in detail here. Warwick Hughes has an article on Isfjord Radio here that makes the case for warming of Isfjord Radio due to moving of sea ice away from the islands in summer since 1912. Neither station in Svalbard shows on the anomaly map because there was no common station in both the base period and the anomaly period. Here’s a map with 1998 to 2008 as the base period where Svalbard appears.
This is the Krenkel meteorological station on Hayes Island, or Ostrov Kheysa in Russian, in the Franz Josef Land Archipelago, Russia. Link The station has been moved or re-built twice since it was established. It was moved from Hooker Island (article in German) in 1957/58. A fire destroyed the power station in 2000, and it was rebuilt in 2004 closer to the shoreline. The GISS record is from 1958 with a gap from 2001 to 2009. The population was as high as 200 during Soviet times, but is down to 4 or 5 now. The population and the temperature seem to track roughly during Soviet days, and the move in 2004 was to a warmer location. In the picture you can see the old buildings on the ridge in the distance. The red grid-square on the anomaly map above corresponds to this station.
Source: http://www.sevmeteo.ru/foto/15/88.shtml
This is the town of Ust’-Olenek, Russia.
The town doesn’t look like much, but notice the Tundra Buggies parked next to the Stevenson Screens. It is on the Laptev Sea, on the northern Siberia Coast, but on a peninsula on a south-facing beach. The buildings are right on the shore. The wide view above was taken from out on the ice. This is one of the few places in Russia that the Google Earth satellite view actually has enough resolution to see the Stevenson Screens. They are much too close to the heated building.
11. Verhojansk (67.5 N,133.4 E)
This is one of the “centrally heated” towns in Russian Siberia. The picture at the top of this article is of the Stevenson Screen. Verhojansk is called the “cold pole” of the earth, but the measurements are too warm by far. Look closely at the picture. Any photographer will note that the warm glow inside the Stevenson Screen is just the color temperature of an incandescent light bulb. If the steam heat in the town isn’t enough, or the cattle in the pole-barns in the distance, the heat from the light bulb will warm up the measurements. This site was covered on WUWT here and here. Anthony Watts notes that warm anomalies would appear and disappear in this part of Russia “as if a switch were thrown”. Could it be as simple as the switch on that light bulb?
Also spelled Chokurdakh. The population has been dropping in recent years, but was still over 2500 people in 2002. The town is sandwiched between the Indigirka River and the airport. There is no way to tell where the Stevenson Screen is located, but the infrastructure at the airport blends right into the town. See an aerial photo here.
13. Zyrjanka (65.7 N, 150.9 E) Also spelled Zyryanka, another steam-heated town in eastern Siberia, well inland. The airport is in this picture on the north edge of town, along the Kolyma riverbank. This airfield was built during WWII as a stop for aircraft being ferried to the Soviet Union from Alaska. A second airport 7 miles west of town was probably built during the cold war for the military. The town was established in 1931. The population is currently about 3500. During the Soviet Union it was up to 15,000.
14. Mys Smidta (68.9 N,179.4 W)
Or Cape Schmidt. John Daly wrote a bit about this location in 2000 (scroll way down in the article). The population was nearly 5000 in 1989, but has dropped since the fall of the Soviet Union. The population now is probably less than 1000. It is on the north coast of eastern Siberia, nearly at 180° longitude. The airbase there was built in 1954 as a staging base for any bombers headed for the U. S. It is still used by a regional airline.
15. Mys Uelen (66.2 N,169.8 W)
Or Cape Uelen. This is on the easternmost tip of Siberia, across Bering Strait from Kotzebue, Alaska. The current population is about 700 people. It is also centrally steam heated. The town is restricted by the geography, on a narrow spit sticking out into the sea, backed by a cliff on the landward side. The airport is a helipad. Cargo and fuel arrives by barge in the summer.
Below is a temperature chart for many of the above stations. All are warming, some faster than others. Barrow, for which we have the UHI study, is not the fastest warming.
16. Alert,N.W.T.(82.5 N,62.3 W), Alert, Canada
Alert, Canada has had a weather station since 1951. The population has never been more than 4 or 5 in the winter, with a higher population in the summer. I could not definitively locate the Stevenson screen, but there are two possibilities in this photo, both well away from the buildings.
THE ISOLATED STATIONS, NOS. 16-24
17. Resolute,N.W. (74.7 N,95.0 W)
The population of this Canadian station rose from zero prior to 1947, to 229 in 2006. There is an airport here, and the Stevenson Screen can be seen across the aircraft parking area from the airport terminal at the left edge of the photo.
Pictures of the station are here, and a web site is here. The 18 people on the island live at Olonkinbyen, or Olonkin “City”. The meteorological station is 2.6 km away. The 4 people that work there live in Olonkin City. The Stevenson Screen appears to be well away from the station building, and the surroundings have probably not changed since the station was built.
19. Gmo Im.E. K. F (77.7 N, 104.3 E)
This is a Russian station on the Tamyr Peninsula at Cape Chelyuskin (Mys Chelyuskin). Nothing is visible at that location on the Google satellite view, but the resolution is very low. I found an article by Warwick Hughes dated September 2000 that speaks of cooling of the Tamyr Peninsula here. He also talks about “non-climate” warming of Verhojansk and Olenek.
20. Ostrov Dikson (73.5 N,80.4 E
Dikson, Russia airfield
This is Dickson Island in English. There is a town of Dikson 10 kilometers away on the mainland. The airport is on Dikson Island at the point called Ostrov Dikson on the map below. Pictures of the airport can be seen here. The town is pictured on this 1965 stamp.
Wikipedia link
21. Ostrov Kotel’ (76.0 N,137.9 E)
The full name is Ostrov Kotel’nyy. In English this is Kettle Island. The first documented explorer found a copper kettle, so obviously he was not the first person to find the island. A single building is barely visible on Google 3D mapsat the “settlement” known as Kalinina. This may be the meteorological station. No other signs of civilization can be seen on the whole island.
22. Mys Salaurova (73.2 N,143.2 E)
This also spelled Mys Shalaurova. The station is on the south-facing shore of an island and is visible on Google Earth here. There is a tide gauge, and the tide data is on that same page.
23. Ostrov Chetyr (70.6 N,162.5 E)
The full name is Ostrov Chetyrekhstolbovoy. This is a small island in the East Siberian Sea in the Medvezhy Island (Bear Island) group.
Map source here.
A description of the place is found: here. “A polar meteorological station and a radio station are situated on the shore of a small bay which indents the S side of the island.”
24. Ostrov Vrange (71.0 N,178.5 W)
This is otherwise known as Wrangle Island. It is about 125 kilometers off the Siberian coast on the 180th meridian. The weather station is at Ushakovskiy on a spit at Rogers Bay, at the right in this picture, well separated from the village. One building in the village is visible at the left. Link
The population in the village grew to as many as 180 people in the 1980’s, but when the Soviet Union dissolved, subsidies declined and the population moved to the mainland. The last villager was killed by a polar bear in 2003. The population at the weather station, when occupied, has always been 4 or 5.
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Arctic is very little affected by climatic conditions elsewhere in the Northern hemisphere, while it is the critical factor of the North Atlantic temperatures movements.
http://www.vukcevic.talktalk.net/NFC1.htm
Barrow was served by ski plane in winter and float plane in summer until the airstrip was built, which was less than 20 years ago if memory serves. As I recall the airport matches a jump in the Barrow temperature record.
It really is worse than I thought! Corrupted data wherever you look. Thanks for bringing this to our attention!
This is a great post. It is something that has been crying out to be written for some time. With mapping station data it was pretty clear to us that there are many stations in the Arctic where, for the period up to 1939 and the more recent period, warming is similar in both rate and extent. The ‘sine wave’ that follows the AMO shows up in the data forArctic stations we included here:
http://diggingintheclay.wordpress.com/2010/09/01/in-search-of-cooling-trends/
The ‘cooling trends’ of the title are only due to the temperatures in the 1930s being higher than present.
Incidentally in GHCNV3, our preliminary analyses show extended periods for many Arctic stations (among others) – i.e. data for longer periods than in GHCNV2. This is particularly noticable in the Canadian Arctic. Blog post on it soon.
Excellent. This is important data. If places like CRU were not so distracted by having to make the case for AGW, they could be doing this sort of basic, decent work to add to our knowledge.
Ed Caryl: Thanks.
This betrays a fundamental misunderstanding of statistics. The R^2 value is a measure of linear dependence between two (random) variables, and nothing more. A trend with extremely high significance may still have a low R^2 if the trend is non-linear or if the observations are noisy.
Can you clarify how you classified sites as “urban” and “rural”? The inclusion of Eureka and Nord Ads in “urban” seems problematic, as you mention that each site has a winter population of less than ten. If these sites are switched to “rural”, then the “rural” sites are on average at a higher latitude than the “urban” ones (Wilcoxon rank sum test, p = 0.014) and that alone may explain away the whole pattern.
“and that alone may explain away the whole pattern.”
Not so. It is the trend that is being considered, not the absolute temperature.
Interesting. Here is what I do not like about his work, at least as I understand it — I would greatly prefer to see this work done on some sort of double-blind system. One group, without any knowledge of station temperature numbers, sorts the stations (e.g. urban vs. rural) while another works on the temperature trends. This way there is no danger of the sorting decisions being pre-biased by knowledge of their characteristics (something that arguably happens all the time in dendro-climatology).
I’m sure these stations are not cheap, but they are not that expensive either (compared to, say, the cost of CO2 reduction). It should be simple to get a set of ~10 identical stations set at various locations within a few km of each other.
Place them varying distances and directions from a location like Barrow AK. Then see if there is a correlation for temperature with various factors like distance, direction, wind direction, wind speed, etc. For example, if the “downwind” thermometers tend to read high, then that would be a clear indication of the UHI effect.
The same would apply to ANY site. This seems like a simple step to quantify the significance of UHI affects. With matched thermometers, it should be easy to spot differences of 0.1 C from station to station.
One of the hallmarks of a good scientific study is repeatability. Before investing trillions in mitigation, we should invest a few million in studying the equipment and siting. I have never heard of such a study, but I admit I am not familiar with climatology studies. Does anyone know of such an experiment ever being done?
Maud Kipz wrote: “If these sites are switched to “rural”, then the “rural” sites are on average at a higher latitude than the “urban” ones and that alone may explain away the whole pattern.”
Can you volunteer any hypothesis as to why that may be? AFAIAA, the arctic is postulated to be one place where the warming effect of CO2 will be most visible ie high warming trends. Why then, as you travel further north, would the warming trend seem to completely disappear? These results need careful examination.
Yes, Nord has less than 10 people in the winter. But they have a lot of infrastructure to maintain. They keep the runway plowed 300 days a year. This requires the snowplows to be kept in heated garages, otherwise there is no starting them. They keep many sled-dogs there because it is also a base for the Sirius Patrol, so the population is more than people. Fuel tanks and the power generator are outside and heated. Diesel fuel is a thick gell at -40 C, so must be heated.
One of the problems with arctic stations is that no one wants to go very far outside in the winter, so the instruments tend to be too close to the heated buildings.
“double-blind system”?
A bit hard to do when there is just me!
Tim F
Yes, it was done for Barrow. See the link in the Barrow discussion.
Ice doesn’t melt by suggestion or supposition and the overall Arctic trend is undoubtedly downward. Have you looked at the most recent ice extent data (“ruh-roh!”)?
“Ice doesn’t melt by suggestion or supposition and the overall Arctic trend is undoubtedly downward”
Arctic sea ice melts primarily from warm water enering the Arctic ocean past Spitzbergen. There has been lots of such water of late following the effect of 30 years of strong El Ninos working it’s way poleward.
Such ocean cycles are perfectly capable of reducing Arctic sea ice even whilst the Arctic air might be on a slow downward trend if UHI effects are properly excluded.
While publishing their article in English, authors should use correct English transliterations of Russian geographical names, rather than mixing German- and English-style transliterations (for example, should be “Verkhoyansk”, not “Verhojansk” — the latter is how Germans write it).
Have you looked at the most recent ice extent data (“ruh-roh!”)?
Have You?
http://www.ijis.iarc.uaf.edu/seaice/extent/AMSRE_Sea_Ice_Extent_L.png
Maud Kipz says: at 9:08 am
“This betrays a fundamental misunderstanding of statistics.”
That caught my attention also. Regarding “r” or the Pearson product-moment correlation coefficient:
“It is widely used in the sciences as a measure of the strength of linear dependence between two variables.”
http://en.wikipedia.org/wiki/Pearson_product-moment_correlation_coefficient
The graphic with the above article might be helpful for some folks. The following is more directly related to the issue raised by Maud Kipz’s comment:
Regarding r^2 or the “Coefficient of Determination”
“is useful because it gives the proportion of the variance (fluctuation) of one variable that is predictable from the other variable.”
http://mathbits.com/mathbits/tisection/statistics2/correlation.htm
Note the word “proportion” in the quote.
As I prepared Ed’s essay for WordPress, I also checked many other surface station plots of other locations.
I noticed a lot of boomerangs out there, and very few hockey sticks.
Tim, see the Hinkel study cited for Barrow UHI. Basically as you describe.
Murray, State archives show Barrow airport construction in the 60s. I suspect that there was an earlier crude strip in support of NPR-A and DEW line work. Latest temp trend jump takes place as pipeline worked ramped up. The town has doubled in size and its housing and other facilities have been constructed or steadily improved, enlarged, etc., over the last 30 years.
I thought this was a terrific, painstaking article. I immediately recalled the posts here by Roy Spencer about UHI vs population density (identified with the help of Rick Wermer’s excellent guide, see large blue/purple button at top right of WUWT home page):
http://wattsupwiththat.com/2010/03/03/spencer-using-hourly-surface-dat-to-gauge-uhi-by-population-density/
http://wattsupwiththat.com/2010/03/04/spencers-uhi-vs-population-project-an-update/
http://wattsupwiththat.com/2010/03/10/spencer-global-urban-heat-island-effect-study-an-update/
What Dr. Spencer said at the first URL above was:
“This graph shows that the most rapid rate of warming with population increase is at the lowest population densities. The non-linear relationship is not a new discovery, as it has been noted by previous researchers who found an approximate logarithmic dependence of warming on population.
“Significantly, this means that monitoring long-term warming at more rural stations could have greater spurious warming than monitoring in the cities. For instance, a population increase from 0 to 20 people per sq. km gives a warming of +0.22 deg C, but for a densely populated location having 1,000 people per sq. km, it takes an additional 1,500 people (to 2,500 people per sq. km) to get the same 0.22 deg. C warming. (Of course, if one can find stations whose environment has not changed at all, that would be the preferred situation.)”
Even relatively small populations (20 people) can give rise to detectable UHI increases. And if there is an airstrip and special heating arrangements (external pipes) as in some of the arctic stations, the UHI might be even more marked than in non-arctic sites without these.
I co-authored a paper on just this subject several years back:
http://climate.gi.alaska.edu/ResearchProjects/pages/AKpaper2.html
The Urban Heat Island Effect at Fairbanks, Alaska
N. Magee1, J. Curtis2, and G. Wendler2
(1) The Pennsylvania State University, University Park, PA 16802
(2) Geophysical Institute, University of Alaska Fairbanks, Fairbanks AK 99775
Abstract
Using surface observation comparisons between Fairbanks and rurally situated Eielson Air Force Base in Interior Alaska, the growth of the Fairbanks heat island was studied for the time period 1949-1997. The climate records were examined to distinguish between a general warming trend and the changes due to an increasing heat island effect. Over the 49-year period, the population of Fairbanks grew by more than 500%, while the population of Eielson remained relatively constant. The mean annual heat island observed at the Fairbanks International Airport grew by 0.4°C, with the winter months experiencing a more significant value of 1.0°C. Primary focus was directed toward long-term heat island characterization based on season, wind speed, cloud cover, and time of day. In all cases, minimum temperatures were affected more than maxima and periods of calm or low wind speeds, winter clear sky conditions, and nighttime exhibited the largest heat island effects.
You can download a pdf version of the paper at the above link.
Actually, this “sort of experiment” is ongoing everywhere, but not to the rigor Tim F. is suggesting. For example, in Texas there are several pairs of stations that are about 50km apart, yet their 100-year trend is OPPOSITE. Mainstream climatology ignores this obvious sore by claiming “good spatial correlation” between stations in radius up to 1200km. Yes, I checked the correlation function between Ada and Pauls Valley stations, see
http://ourchangingclimate.wordpress.com/2010/05/21/scott-denning-to-iccc-heartland-%E2%80%98conference%E2%80%99-gathering-%E2%80%9Cbe-skeptical%E2%80%A6-be-very-skeptical%E2%80%9D/#comment-5761
It was about 0.77. However, what has escaped an attention of climate researchers (Hansen-Lebedeff) is that this correlation is made from high-amplitude inter-seasonal excursions, which are obviously well correlated, especially when 50km apart. The main parameter or our interest, the long-term trend, is however totally opposite. Similar pairs of stations with strictly opposite climatologically-long trends can be found everywhere – see more fun in the referenced thread.
Interestingly, this observation of inconsistency between uniform forcing and opposite trends in nearby stations does not have a traction in skeptical community either:
http://wattsupwiththat.com/2010/06/17/an-aggie-joke/#comment-414419
http://noconsensus.wordpress.com/2010/09/02/in-search-of-cooling-trends/#comment-35835
I have a reservation that “UHI effect” can impose only uptrend. There could be also a downtrend. All would depend on location of a particular sensor relative to the center of heat island. If the sensor is situated on outskirt of the heat spot, convective pattern of airflow will draft surrounding air masses and bias the main wind pattern, and likely cause some cooling trend if the heat island grows over historical time. So, without actual measurements from oversampled grid of temperature sensors all these “UHI corrections” are likely a BS.