UHI? What UHI?

[IanC]

This is obviously a cartoon. I don't actually believe zebras are lining in Siberia.

It does point out the problems of identifying warming trends in polar regions. Is Barrow Alaska really one of the fastest warming places on the globe, or does the actually measured UHI have something to do with it? Many northern stations are at airports. Does the propwash or jet exhaust from increased flights have anything to do with the rising trend, which has been increased by adjustments and homogenization rather than lowered.

 

[mamooth]

Urban stations haven't warmed any faster than rural stations.

Hence, your theory is conclusively disproved.

 

[IanC]

Urban stations haven't warmed any faster than rural stations.

Hence, your theory is conclusively disproved.

More specious claims. You present your evidence and I'll counter it.

 

[mamooth]

Science normally requires affirmative evidence for your own claim, instead of declaring that your speculation has to be assumed to be correct unless disproved. But hey, still no problem to disprove it.

Urbanization effects in large-scale temperature records, with an emphasis on China
Jones et al (2008)

Urbanization effects in large-scale temperature records, with an emphasis on China - Jones - 2008 - Journal of Geophysical Research: Atmospheres - Wiley Online Library
---
We show examples of the UHIs at London and Vienna, where city center sites are warmer than surrounding rural locations. Both of these UHIs however do not contribute to warming trends over the 20th century because the influences of the cities on surface temperatures have not changed over this time. In the main part of the paper, for China, we compare a new homogenized station data set with gridded temperature products and attempt to assess possible urban influences using sea surface temperature (SST) data sets for the area east of the Chinese mainland. We show that all the land-based data sets for China agree exceptionally well and that their residual warming compared to the SST series since 1951 is relatively small compared to the large-scale warming. Urban-related warming over China is shown to be about 0.1°C decade−1 over the period 1951–2004, with true climatic warming accounting for 0.81°C over this period.
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Assessment of Urban Versus Rural In Situ Surface Temperatures in the Contiguous United States: No Difference Found
Peterson (2003)

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Using satellite night-lights–derived urban/rural metadata, urban and rural temperatures from 289 stations in 40 clusters were compared using data from 1989 to 1991. Contrary to generally accepted wisdom, no statistically significant impact of urbanization could be found in annual temperatures.
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A Demonstration That Large-Scale Warming Is Not Urban
Parker (2006)

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On the premise that urban heat islands are strongest in calm conditions but are largely absent in windy weather, daily minimum and maximum air temperatures for the period 1950–2000 at a worldwide selection of land stations are analyzed separately for windy and calm conditions, and the global and regional trends are compared. The trends in temperature are almost unaffected by this subsampling, indicating that urban development and other local or instrumental influences have contributed little overall to the observed warming trends.
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[flacaltenn]

Urban-related warming over China is shown to be about 0.1°C decade−1 over the period 1951–2004, with true climatic warming accounting for 0.81°C over this period.

How strange.. Can't do multiplication in China? .1deg/dec from 1950 to 2004 would be 0.55degC..
Kinda shoots their opening premise in the foot..


And London and Paris are kinda of fully packed urban centers with not much expansion and probably LESS energy use than 20 years ago.. That's not the effect you want to investigate -- is it??

 

[flacaltenn]

This is obviously a cartoon. I don't actually believe zebras are lining in Siberia.

It does point out the problems of identifying warming trends in polar regions. Is Barrow Alaska really one of the fastest warming places on the globe, or does the actually measured UHI have something to do with it? Many northern stations are at airports. Does the propwash or jet exhaust from increased flights have anything to do with the rising trend, which has been increased by adjustments and homogenization rather than lowered.

Cartoon reminds me of an enviro story from about 5 yrs ago. When Florida Power/Light was forced to cut the BTUs in their cooling water from some of their riverside power plants. A year later they noticed a big reduction in the Manatee populations locally. Those critters spend THEIR winters around those plants. I could have told them that was gonna happen. One of the justifications for reducing the heat? Concern for the manatees...

 

[Billy_Bob]

This is obviously a cartoon. I don't actually believe zebras are lining in Siberia.

It does point out the problems of identifying warming trends in polar regions. Is Barrow Alaska really one of the fastest warming places on the globe, or does the actually measured UHI have something to do with it? Many northern stations are at airports. Does the propwash or jet exhaust from increased flights have anything to do with the rising trend, which has been increased by adjustments and homogenization rather than lowered.

Cartoon reminds me of an enviro story from about 5 yrs ago. When Florida Power/Light was forced to cut the BTUs in their cooling water from some of their riverside power plants. A year later they noticed a big reduction in the Manatee populations locally. Those critters spend THEIR winters around those plants. I could have told them that was gonna happen. One of the justifications for reducing the heat? Concern for the manatees...

SO they found out that it was the UHI heat being generated from these plants which coaxed them inland? Dam those unintended consequences... Now out of 'concern for the manatee' they cooled these areas and they have for the most part left the area...

I guess that would solve the majority of problems being hit by boat propellers..

They are no longer there to hit...

 

[Billy_Bob]

UHI is well sourced and well documented. The rise over time is directly correlated to the growth rate of the area and it most certainly does affect the Global Mean Temp rise in a false positive fashion.. This is why they created the US CRN sites which show no warming for 16 years 5 months now and a cooling trend for the last 12 years.

 

[Billy_Bob]

Even the Washington post acknowledges this fact..

Inside Washington, D.C.’s urban heat island effect

"By Brendan Richardson November 21, 2013

Why is it usually considerably warmer in the city than surrounding suburbs, especially at night? Just this morning, for example, the low at Reagan National Airport near the District was 36, while Dulles Airport – 25 miles to the west – bottomed out at 27. These kinds of temperature discrepancies are due to a phenomenon known as the urban heat island effect.

An urban heat island (UHI) is produced within a city center when development adds heat sources into the surrounding air. The added heat comes from tightly packed infrastructure, highly heat-absorbent surfaces like asphalt, and all the vehicles on the road.

Via NASA: ” This image of the U.S. capital city—Washington, D.C.—was acquired on June 1 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), a Japanese sensor flying aboard NASA’s Terra spacecraft.” – from 2000. View large.
The above image shows vegetation coverage for Washington, D.C. using near-infrared (heat) sensors. The rates of heat transfer for trees, plants, and shrubbery occur slower than many thermally conductive urbanized structures. "

 

[IanC]

Science normally requires affirmative evidence for your own claim, instead of declaring that your speculation has to be assumed to be correct unless disproved. But hey, still no problem to disprove it.

Urbanization effects in large-scale temperature records, with an emphasis on China
Jones et al (2008)

Urbanization effects in large-scale temperature records, with an emphasis on China - Jones - 2008 - Journal of Geophysical Research: Atmospheres - Wiley Online Library
---
We show examples of the UHIs at London and Vienna, where city center sites are warmer than surrounding rural locations. Both of these UHIs however do not contribute to warming trends over the 20th century because the influences of the cities on surface temperatures have not changed over this time. In the main part of the paper, for China, we compare a new homogenized station data set with gridded temperature products and attempt to assess possible urban influences using sea surface temperature (SST) data sets for the area east of the Chinese mainland. We show that all the land-based data sets for China agree exceptionally well and that their residual warming compared to the SST series since 1951 is relatively small compared to the large-scale warming. Urban-related warming over China is shown to be about 0.1°C decade−1 over the period 1951–2004, with true climatic warming accounting for 0.81°C over this period.
---

Assessment of Urban Versus Rural In Situ Surface Temperatures in the Contiguous United States: No Difference Found
Peterson (2003)

An Error Occurred Setting Your User Cookie
---
Using satellite night-lights–derived urban/rural metadata, urban and rural temperatures from 289 stations in 40 clusters were compared using data from 1989 to 1991. Contrary to generally accepted wisdom, no statistically significant impact of urbanization could be found in annual temperatures.
---

A Demonstration That Large-Scale Warming Is Not Urban
Parker (2006)

An Error Occurred Setting Your User Cookie
---
On the premise that urban heat islands are strongest in calm conditions but are largely absent in windy weather, daily minimum and maximum air temperatures for the period 1950–2000 at a worldwide selection of land stations are analyzed separately for windy and calm conditions, and the global and regional trends are compared. The trends in temperature are almost unaffected by this subsampling, indicating that urban development and other local or instrumental influences have contributed little overall to the observed warming trends.
---

it is a shame that only one of your links is to the paper itself and the other two are just abstracts. not your fault but it is frustrating that older papers are hard to get a hold of.

first off...everyone agrees that urban areas are warmer than the surrounding rural areas, even the papers you cited. the difficulty lies in deciding how much it goes up and over what time period. Jones picked two cities, London and Vienna, which are fully urbanized and have been for a long time. UHI is a logarithmic function that has its greatest effect for low population density and the early rises, rapidly tapering off. eg- woodland to roads and houses causes a bigger effect than houses to skyscrapers. Jones and his China data is somewhat tainted and his 1990 paper even brought up a fraud investigation against his Chinese collaborator.

Petersen and his night light study examined a three year period? I wish I could read the paper because the abstract is too ambiguous.

likewise for the Parker paper on wind conditions. the abstract doesnt even link to the Suplimental Information where I could at least look at the graphs.

 

[IanC]

I looked around at a lot of papers on UHI and found one very interesting one. F Fujibe 2009. paywalled of course but a lot of the information was posted up at Urban Heat Island in Japan . surely the warmers dont object to him.

anyways, automated weather stations came on line in Japan in 1979 and this paper uses data to 2006. the results-

SoD says-

So, in this very thorough study, in Japan at least, the temperature rise that has been measured over the last few decades is a solid result. The temperature increase from 1979 – 2006 has been around 0.3°C/decade

However, in the larger cities the actual measurement will be overstated by 25%.

And in a time of lower temperature rise, the UHI may be swamping the real signal.

The IPCC (2007) had this to say:

A number of recent studies indicate that effects of urbanisation and land use change on the land-based temperature record are negligible (0.006ºC per decade) as far as hemispheric- and continental-scale averages are concerned because the very real but local effects are avoided or accounted for in the data sets used.

So, on the surface at least, this paper indicates that the IPCC’s current position may be in need of modification.

 

[IanC]

a similar type of article from Roy Spencer. The Global Average Urban Heat Island Effect in 2000 Estimated from Station Temperatures and Population Density Data « Roy Spencer, PhD

steepest rise at the beginning of urbanization

Roy says-

The UHI effect leads to a spurious warming signal which, even though only local, has been given global significance by some experts. Many of us believe that as much as 50% (or more) of the “global warming” signal in the thermometer data could actually be from local UHI effects. The IPCC community, in contrast, appears to believe that the thermometer record has not been substantially contaminated.

Unless someone quantitatively demonstrates that there is a significant UHI signal in the global thermometer data, the IPCC can claim that global temperature trends are not substantially contaminated by such effects.

If there were sufficient thermometer data scattered around the world that

remember what the IPCC says-

The IPCC (2007) had this to say:
A number of recent studies indicate that effects of urbanisation and land use change on the land-based temperature record are negligible (0.006ºC per decade) as far as hemispheric- and continental-scale averages are concerned because the very real but local effects are avoided or accounted for in the data sets used.

 

[IanC]

and what of the adjustments made for UHI? here's a paper on GISS adjustments- http://oprj.net/oprj-archive/climate-science/31/oprj-article-climate-science-31.pdf

ABSTRACT

NASA GISS are currently the only group calculating global temperature estimates that explicitly adjust their weather station data for urbanization biases. In this study, their urbanization adjustment procedure was considered.
A number of serious problems were found with their urbanization adjustments:

1.) The vast majority of their adjustments involved correcting for urban cooling", whereas urbanization bias is predominantly a warming bias.

2.) The net effect of their adjustments on their global temperature estimates was unrealistically low, particularly for recent decades, when urbanization bias is expected to have increased.

3.) When a sample of highly urbanized stations was tested, the adjustments successfully removed warming bias for the 1895-1980 period, but left the 1980s-2000s period effectively unadjusted.

In an attempt to explain these unexpected problems, a critical assessment of their adjustment procedure was carried out. Several serious flaws in their procedure were identified, and recommendations to overcome these flaws were given.
Overall, NASA GISS’ urbanization adjustments were found to be seriously flawed, unreliable and inadequate. Until their adjustment approach is substantially improved, their global temperature estimates should be treated with considerable caution.



this paper is pretty interesting because it gets into the nuts and bolts of a global temperature dataset and shows what is done.

 

[IanC]

another Spencer article on adjusting US temps by population size- U.S. temperatures, 1973-2013: A alternative view « Roy Spencer, PhD

which method is more correct? it's hard to say but it does show that there are many ways to look at temperature datasets and make corrections. Spencer does this sort of stuff as a sideline to running the UAH satellite temp program. imagine if there was a group funded to investigate global temps without the encouragement to conform with 'consensus'.

 

[IanC]

another paywalled paper. Implications of temporal change in urban heat island intensity observed at Beijing and Wuhan stations - Ren - 2007 - Geophysical Research Letters - Wiley Online Library

Abstract
[1] Temporal change in urbanization-induced warming at two national basic meteorological stations of China and its contribution to the overall warming are analyzed. Annual and seasonal mean surface air temperature for time periods of 1961∼2000 and 1981∼2000 at the two stations of Beijing and Wuhan Cities and their nearby rural stations all significantly increase. Annual and seasonal urbanization-induced warming for the two periods at Beijing and Wuhan stations is also generally significant, with the annual urban warming accounting for about 65∼80% of the overall warming in 1961∼2000 and about 40∼61% of the overall warming in 1981∼2000. This result along with the previous researches indicates a need to pay more attention to the urbanization-induced bias probably existing in the current surface air temperature records of the national basic stations.

these guys are saying that more than half of the post-1960 warming is due to urbanization in the two big Chinese cities under study. how does that fit into the IPCC's 0.006C/decade?

 

[Billy_Bob]

"In an attempt to explain these unexpected problems, a critical assessment of their adjustment procedure was carried out. Several serious flaws in their procedure were identified, and recommendations to overcome these flaws were given.

Overall, NASA GISS’ urbanization adjustments were found to be seriously flawed, unreliable and inadequate. Until their adjustment approach is substantially improved, their global temperature estimates should be treated with considerable caution. "

The word "ouch" comes to mind with that scathing rebut .

 

[westwall]

another paywalled paper. Implications of temporal change in urban heat island intensity observed at Beijing and Wuhan stations - Ren - 2007 - Geophysical Research Letters - Wiley Online Library

Abstract
[1] Temporal change in urbanization-induced warming at two national basic meteorological stations of China and its contribution to the overall warming are analyzed. Annual and seasonal mean surface air temperature for time periods of 1961∼2000 and 1981∼2000 at the two stations of Beijing and Wuhan Cities and their nearby rural stations all significantly increase. Annual and seasonal urbanization-induced warming for the two periods at Beijing and Wuhan stations is also generally significant, with the annual urban warming accounting for about 65∼80% of the overall warming in 1961∼2000 and about 40∼61% of the overall warming in 1981∼2000. This result along with the previous researches indicates a need to pay more attention to the urbanization-induced bias probably existing in the current surface air temperature records of the national basic stations.

these guys are saying that more than half of the post-1960 warming is due to urbanization in the two big Chinese cities under study. how does that fit into the IPCC's 0.006C/decade?

It doesn't. What has become very clear is the IPCC is very adept at pulling numbers out of its ass that bear no relationship to reality.

 

[IanC]

caption- Surface temperatures vary more than air temperatures during the day, but they both are fairly similar at night.

from NASA - Satellites Pinpoint Drivers of Urban Heat Islands in the Northeast

the UHI effect is real. often many degrees Celcius. it happens over long time spans usually, so it is not 'caught' by homogenization techniques. GISS is the only temp database that specifically adjusts for UHI and the net adjustment is 0C. nada, zilch. is that realistically possible? BEST actually claims that UHI is negative and therefore has to increase recent temps to make up for it. really?

there are a great many problems with global temp datasets. UHI is one, but probably not a very important one. what IS important is how it is treated. does anyone really believe it is neutral, or worse, causes cooling? preposterous! but that is the crap we are being told, and how the adjustments are being made for UHI.

think about it. if one obvious effect is being twisted in this way, how many others that we dont actually see for ourselves are also being 'massaged' to give a pleasing result for the alarmists?

 

[flacaltenn]

caption- Surface temperatures vary more than air temperatures during the day, but they both are fairly similar at night.

from NASA - Satellites Pinpoint Drivers of Urban Heat Islands in the Northeast

the UHI effect is real. often many degrees Celcius. it happens over long time spans usually, so it is not 'caught' by homogenization techniques. GISS is the only temp database that specifically adjusts for UHI and the net adjustment is 0C. nada, zilch. is that realistically possible? BEST actually claims that UHI is negative and therefore has to increase recent temps to make up for it. really?

there are a great many problems with global temp datasets. UHI is one, but probably not a very important one. what IS important is how it is treated. does anyone really believe it is neutral, or worse, causes cooling? preposterous! but that is the crap we are being told, and how the adjustments are being made for UHI.

think about it. if one obvious effect is being twisted in this way, how many others that we dont actually see for ourselves are also being 'massaged' to give a pleasing result for the alarmists?

Must gripe the heck out of the "Space Science" guys at GISS -- that satellites can actually quantify the UHI quite nicely.

"This, at least to our knowledge, is the first time that anybody has systematically compared the heat islands of a large number of cities at continental and global scales," said Ping Zhang, a scientist at Goddard and the lead author of the research.

SURE --- it's all "settled"...

 

[mamooth]

does anyone really believe it is neutral, or worse, causes cooling? preposterous!

Argument from incredulity fallacy. It's no longer a matter of whether you'll use fallacies, just a matter of which one it will be.

the UHI effect is real. often many degrees Celcius. it happens over long time spans usually, so it is not 'caught' by homogenization techniques. GISS is the only temp database that specifically adjusts for UHI and the net adjustment is 0C. nada, zilch. is that realistically possible? BEST actually claims that UHI is negative and therefore has to increase recent temps to make up for it. really?

So you don't understand the basics, the differences between using anomalies and absolute temperatures.

Scientists don't have that problem, and your failure to understand doesn't reflect badly on them.