Urban heating and what drives it

I was surprised that Anthony Watts hasn't copied and pasted a press release about a new paper on urban heat island effect. It's one of his very favourite subjects. I guess he missed it.

The paper has been published in Nature and I spotted the press release about it a couple of days ago when scanning ScienceDaily.com. The article describes research from scientists Lei Zhao, Xuhui Lee, Ronald B. Smith and Keith Oleson. It's an international collaboration. The scientists hail from Nanjing University of Information Science and Technology, Yale University and the National Center for Atmospheric Research in Boulder, Colorado.

What they did was look in some detail at the various contributions to warming associated with the growth of towns and cities. In particular, they analysed data for 65 cities across North America.

Urban heating has implications not just from a comfort perspective but from a health perspective. Research on the subject can help cities mitigate against this human-caused warming.

After dark, the main contributor to urban heating is the buildings and roads etc releasing heat stored during the day. That confirmed what was already thought.

During the daytime, however, it's related to the efficiency of convection and humidity. As described in the abstract:  "If urban areas are aerodynamically smoother than surrounding rural areas, urban heat dissipation is relatively less efficient and urban warming occurs (and vice versa)."

There's more. Here is an extract from ScienceDaily.com

Their results reaffirmed the consensus view that, regardless of the local climate, the release of heat stored in human-built structures is the dominant contributor to UHI during the nighttime.

But during the daytime, researchers found, convection is the dominant factor -- particularly in "wetter" cities of the southeastern United States. In those places, the smooth surfaces of buildings and other human-made features are far less conducive to heat diffusion than the densely vegetated areas that surround them. Overall, in wetter climates urbanization reduces convection efficiency by 58 percent.

"The 'rougher' surfaces of the vegetation triggers turbulence, and turbulence removes heat from the surface to the atmosphere," said Lei Zhao, a doctoral student at F&ES and lead author of the study. "But where there is a smoother surface, there is less convection and the heat will be trapped in the surface."

Convection plays a key role in drier cities, too -- albeit with far different consequences. In those settings -- including in urban areas of the U.S. Southwest where surrounding vegetation is typically shorter and scrubbier -- the rural areas are less effective at dissipating heat. As a result, the urban landscapes are actually 20 percent more efficient in removing heat than their rural surroundings, triggering a 1.5-degree C cooling within the cities.

That's interesting. I wonder if Anthony Watts has compared temperature trends in drier cities and surrounding rural areas with those in wetter cities and surrounding rural areas?

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Lei Zhao, Xuhui Lee, Ronald B. Smith, Keith Oleson. "Strong contributions of local background climate to urban heat islands". Nature, 2014; 511 (7508): 216 DOI: 10.1038/nature13462

Denier weirdness: Russian steam pipes are causing global warming, sez Anthony Watts @wattsupwiththat

Shades of "Airport UHI Disease".

Today Anthony Watts muses whether one reason this November was the hottest in the instrumental record is because of Russian steam pipes!

Here's the global temperature anomaly according to NASA GISTemp:

Data source: NASA

Here's a chart of the global temperature anomaly for November 2013:

Source: NOAA

In an article protesting the record warm November, Anthony wrote (archived here):

Addendum: I have been wondering about that Russian red spot for 5 years. I’ve seen this red spot come and go in Russia, and I don’t know what the reason is.

I do know this: neither I nor NOAA has a good handle on the siting characteristics of Russian weather stations. I do know one thing though, the central heating schemes for many Russian cities puts a lot of waste heat into the air from un-insulated steam pipes

...and he proceeded to post a lot of photos of steam pipes in Russian cities.

I guess the Russians only turn on their steam pipes in hot Novembers, not cooler Novembers like last year?

Source: NOAA Nov 2013 and Nov 2012

It looks as if they turn on the steam pipes in outback Australia when it's a cold November worldwide.  This year Alaska (and south west USA) turned on the steam pipes but last November they neglected to turn them on in Alaska.  They didn't turn them on in north east North America this year, either - I bet they were wishing they were in northern Russia last month, where they could warm themselves up with the steam pipes!

Here's more PROOF that the steam pipes are only turned on in hot Novembers:

Source: NOAA Nov 2011 and Nov 2010

Once again, when it's a colder November worldwide, they turn on the steam pipes in Australia - but in different parts of the country.  In northern Canada they are quite inconsistent about turning on the steam pipes.

Here's an animation with a map of world population distribution together with the global surface temperature anomaly for November this year.  Those Russians are dreadfully inefficient piping all the steam into unpopulated areas of the country, aren't they.

Sources: NOAA and Maps.com

Kenji, the scientific dog, is probably feeling rather embarrassed again.







Remember when Anthony decided that China was getting hotter because of UHI disease?  Trouble was that the warm anomalies were greatest in parts where almost no-one lived!

From the WUWT comments

Comments are archived here with the WUWT article.

Justin Hoffer thinks there shouldn't be any anomalous anomalies and decides it must be the Russian military equipment messing with the data says:

December 19, 2013 at 1:11 pm
I should clarify that I mean it could be caused by someone messing with the satellite data in some way, or Russian military equipment possible messing with the satellite data. As is, the very existence of an anomaly like that seems rather odd to me.

vukcevic says b..b..but it was cooler in central England this November:

December 19, 2013 at 3:24 pm
Most of ordinary people are concerned about and judge global warming by events in their area; in Central England both maximum and minimum daily temperatures this November were lower than in 2012

jmorpuss is an ordinary nutter and says:

December 19, 2013 at 3:55 pm
Google giant Tesla coils found in Russia . Once found you will ask what the ****? What are they used for? I don’t think their water slides lol.

mike g is a climate conspiracy nutter and says:

December 19, 2013 at 4:19 pm
If the conspicuous and suspicious temperature anomaly over Russia was a cold anomaly, mainstream science would have corrected it. There is enough information in this post and others on here over the years for any reasonable individual to see the data is suspect and has been for years. Yet, it is accepted without question by warmists.

Bombshell: Anthony Watts sez UHI only happens very rarely ... or E-Cat eat your heart out!

Anthony Watts has a new article up at WUWT.  From what he writes, he now thinks that UHI only happens very rarely.  His post is a stark rebuttal to a study of night time heat waves in the north west of the United States.

First the study itself, from ScienceDaily (note the image is from an earlier poster, so it's probably not the final version but it's easier to see the colour differences than the image in ScienceDaily):

The colors represent different ways of processing the historical readings.
Source: K. Bumbaco / UW poster - not ScienceDaily or the paper

University of Washington research shows that the region west of the Cascades saw only three nighttime heat waves between 1901 and 1980, but that number quadrupled to 12 nighttime heat waves in the three decades after 1980, according to a paper published in the July issue of the Journal of Applied Meteorology and Climatology.

Nighttime heat waves are when the daily low is in the top 1 percent of the temperatures on record -- in Seattle above around 61.5 F -- for at least three nights in a row.

"In general, minimum daily temperatures have been warming faster than maximum temperatures, so we're not surprised to see a trend in the minimum events," said corresponding author Karin Bumbaco, a research scientist at the Joint Institute for the Study of the Atmosphere and Ocean. "Still, we were surprised to see this significant increase in the frequency of nighttime heat waves."

...They studied temperature readings west of the Cascade Mountains in Washington and Oregon from 1901 to 2009, looking for instances where the daytime high or nighttime low temperature hit the top 1 percent of readings for at least three consecutive days.

The 2009 scorcher set records in daytime temperature, but it was the string of warm nights that stood out, Bumbaco said. By their definition it was a three-day daytime heat wave in the Pacific Northwest -- but included eight consecutive hot nights, the longest seen in the observational record.

...Researchers also found a clue to suggest why we're seeing more hot nights. It's well known that Pacific Northwest heat waves occur when breeze off the ocean is replaced with air flow from the east, which warms up as it flows down the western slope of the Cascade Mountains.

But they found another trait for nighttime heat waves. The records show that nighttime heat waves happen during high humidity, where water vapor in the air serves as a blanket to trap heat.

Read more. 

E-Cat eat your heart out!

What Anthony Watts discovered will amaze and maybe disappoint you.  The heat waves weren't caused by high humidity preventing the heat escaping to space.  Guess what they were caused by.  Yep, you guessed it.  They were caused by UHI at the Seattle Tacoma Airport, which miraculously heated up at night time for at least three nights in a row on no less than twelve occasions in the years since 1980.  And the effect was so huge on those twelve occasions that it heated up the night time air of entire north-west of the USA, west of the Cascades.

Here's all the proof anyone needs, provided by esteemed blog-sciencyintist Anthony Watts himself:

It would seem that every so often, the UHI night switch is turned on at Seattle airport and the whole of north western USA heats up. No-one has yet discovered why that happens, but it undoubtedly happens because WUWT sez so.  Here are some of the comments at WUWT, which might give blog sciencyintists a clue as to the cause, and offer insights for future blog research:

Chris @NJSnowFan says:

July 22, 2013 at 2:09 pm  I did not read anything about how Jet powered aircraft traffic has also increased at day and night or how Commercial Jet travel was not around before the 1970′s Prop powered aircraft put off way less heat. Jet engines are Giant blower heaters so having a temp gauge reading station anywhere near a runway will NEVER be accurate.

brians356 says:

July 22, 2013 at 2:13 pm Please consider SeaTac opened a 3rd runway in 2008, arguably increasing the paved area surrounding the GHCN station by more than 50%.

Larry Hamlin says:

July 22, 2013 at 3:26 pm Sounds like this is clearly linked to UHI effects for land based temperatures.

Philip Bradley says:

July 22, 2013 at 4:28 pm  (blah blah blah) UHI looks the likeliest reason.

And once wasn't enough for Philip Bradley:

July 22, 2013 at 4:55 pm UHI, including the effect of reduced urban aerosols, looks the likeliest reason.

Tip for people in Oregon and Washington State

The next time you have a few hot nights, don't go out and buy an air conditioner.  Write to your Senator and the Mayor and the local school teacher and whoever else you can think of and get them to shut down Seattle airport. That's wots causing all them night time heat waves! Ain't blog science just great.

Bumbaco, Karin A., Kathie D. Dello, Nicholas A. Bond, 2013: History of Pacific Northwest Heat Waves: Synoptic Pattern and Trends*. J. Appl. Meteor. Climatol., 52, 1618–1631.
doi: http://dx.doi.org/10.1175/JAMC-D-12-094.1

Anthony Watts is Extremely Hot on China

There is a new paper out in Geophysical Research Letters: Wen, H. Q., X. Zhang, Y. Xu, and B. Wang (2013), Detecting human influence on extreme temperatures in China, Geophys. Res. Letters, 40, doi:10.1002/grl.50285.

Heat Extremes in China

An excerpt from the news release:

WASHINGTON – Humans are responsible for increasingly warm daily minimum and maximum temperatures in China, new research suggests. The study is the first to directly link greenhouse gas emissions with warmer temperature extremes in a single country, rather than on a global scale, according to the paper's authors.

"There is a warming in extreme temperatures over China, and this warming cannot be explained by natural variation," said Qiuzi Han Wen, an author on this paper and a researcher at the Institute of Atmospheric Physics in Beijing, China. "It can only be explained by the anthropogenic external forcings. These findings indicate very clearly that climate change is not just an abstract number for the globe; it is evident at regional scale."

Watts' UHI Fixation

Anthony Watts writes - you guessed it:

But the only forcing they considered was GHG’s. Nary a word exists in the paper about UHI, urban heat island, station siting, of heat sync (sic) effects.

It's true that the paper doesn't mention UHI. It's likely that is already taken into account as part of the quality control to which the paper refers:

China’s National Climate Center has recently compiled and quality controlled an extensive daily temperature data set [Wu and Gao, 2012]. Records of daily maximum, daily minimum, and daily mean temperatures were collected from 2416 observation stations from 1961 to 2007.

Thing is, if Anthony was correct and the quality control process for some reason omitted to allow for UHI, would one expect the greatest increase in extreme temperatures to be in areas of greatest population growth?

Compare the Maps

Now the maps I've come across don't show population growth but they do show population density.  Let's just look at the maps and compare them to the charts showing trends in the maxima (Tx) and minima (Tn) temperatures in the paper (click images to enlarge).

TXx = annual maxima of daily maximum (TXx) temperatures 

TNx = annual maxima of daily minimum (TNx) temperatures 

TXn = annual minima of daily maximum (TXn) temperatures

TNn = annual minima of daily minimum (TNn) temperatures

Here is a population map from Wikipedia showing that the temperature trends don't align well with areas of greatest population density.

Should we let Anthony know that the population maps of China must be wrong?

Denier weirdness: It's not CO2, it's aeroplanes

More denier weirdness from WUWT.  Willis Eschenbach has decided that it's not CO2 that's causing global warming, it's occasional landings at remote airports.

Maybe that's what HotCopper's beretta based this idea of his on.

Just for fun, let's analyse what Willis E is saying.

On day one an aeroplane (A1) lands at a remote airstrip.  On day 61 another aeroplane (A2) lands on that same remote airstrip.  The heat produced by aeroplane A1 defies physics and doesn't dissipate, it has magically hung around and is added to the heat produce by aeroplane A2.  After twenty years and (let's be extravagant) 500 landings, the temperature at that remote airstrip has risen by the amount of heat from A1 + A2...A500.

Sheesh, that airstrip is probably really hot by now isn't it.  No wonder the world is heating up :D

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Addendum:

To show how sceptical "fake sceptics" are, and whether or not they check sources, compare the following comment from a WUWT reader...

sunshinehours1 says:
April 4, 2013 at 9:20 am   UHI exists. If the BEST team can’t find UHI, they should keep trying. And quit pretending UHI doesn’t exist.

...with the first paragraph of the BEST paper that Willis 'discusses'.

The Urban Heat Island (UHI) effect describes the observation that temperatures in a city are often higher than in its rural surroundings. London was the first urban heat island to be documented [1] but since then many cities have been identified as urban heat islands [2-5]. A well-known example is Tokyo where the temperature has risen much more rapidly in the city than in nearby rural areas: Fujibe estimates excess warming of almost 2°C/100yr compared to the rest of Japan [6] The warming of Tokyo is dramatic when compared to a global average as seen in Figure 1. The UHI effect can be attributed to many physical differences between urban and rural areas, including absorption of sunlight, increased heat storage of artificial surfaces, obstruction of re-radiation by buildings, absence of plant transpiration, differences in air circulation, and other phenomena [7].

Note for fake sceptics: The BEST paper is not disputing UHI (which is real, was first discussed more than two centuries ago and has been well-documented by climate scientists for decades).  It is looking to see if UHI has biased the record of global land surface temperature anomalies or if it has already been sufficiently factored in or is otherwise inconsequential.  Like every other similar (published) analyses, it has concluded UHI has not biased the records.