2010-08-16 21:53:12Basic answer for 20: Urban heat island effect REVISED
mothincarnate

wow.the.moth@gmail...
118.210.139.18

Urban Heat Islands: serious problem or holiday destination for deniers?

 

The Urban Heat Island Effect (UHI) is a phenomenon whereby the concentration of structures and waste heat from human activity (most notably air conditioners and internal combustion engines) results in a slightly warmer envelope of air over urbanised areas when compared to surrounding rural areas. It has been suggested that UHI has significantly influenced temperature records over the 20th century with rapid growth of urban environments.

Scientists have been very careful to ensure that UHI is not influencing the temperature trends. To address this concern, they have compared the data from remote stations (sites that are nowhere near human activity) to more urban sites. Likewise, investigators have also looked at sites across rural and urban China, which has experienced rapid growth in urbanisation over the past 30 years and is therefore very likely to show UHI. The difference between ideal rural sites compared to urban sites in temperature trends has been very small (see figure 1).

 

Figure 1. Annual average temperature anomalies. Jones et al (dotted green and brown) is a dataset of 42 rural and 42 urban sites. Li et al (solid green and brown) is a homogenized dataset of 42 rural and 40 urban sites. Li (blue) is a non-homogenized set of 728 stations, urban and rural. CRUTEM3v (red) is a land-only data set (Brohan et al., 2006). This plot uses the 1954–83 base period.

Another way to explore the UHI would be to look at where the majority of warming has occurred across the globe. The UHI should match where most people live. However, if you look at the 2006 global temperature anomaly (figure 2.), you find that the greatest difference in temperatures for the long term averages where across Russia, Alaska, far north Canada and Greenland and not where major urbanisation has occurred.

Figure 2. Using source data from NASA/GISS, this illustration shows the amount of change in global surface temperatures in 2006 from 1885.

The Urban Heat Effect has no significant influence on the record of global temperature trends.
2010-08-16 21:54:22
mothincarnate

wow.the.moth@gmail...
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Short, I know - I'm hoping for concise! lol
2010-08-16 23:55:10Comment
Robert Way

robert_way19@hotmail...
24.224.230.22
There have been several analysis done on rural versus urban. Check out clear climate code, tamino's blog and lucia the blackboard. Furthermore Tamino had a recent post which looked at this argument also.
2010-08-17 00:02:55
Ari Jokimäki

arijmaki@yahoo...
91.154.102.68

I think the last sentence is wrong - UHI does influence the temperature data. Perhaps you should change it to something like: The Urban Heat Effect's influence to the global temperature trends is not significant.

Is it normal practice to write terms like urban heat effect with capital letters? For some reason it bothers me.

2010-08-17 02:37:28Admirable, but...
gpwayne
Graham Wayne
graham@gpwayne...
86.156.59.156

Hey Tim - nice to bump into you again...

...and can I say your post is a marvel of economy. That said, you might consider providing a little more information. For example, the relationship between satellite and ground-based measurements, the creation of a formal network of non-affected stations (the Reference Network) and perhaps a mention that older sites (higher incidence of UHI) displayed negative bias - they were under-reporting temperatures.

2010-08-17 03:49:01
Anne-Marie Blackburn
Anne-Marie Blackburn
bioluminescence@hotmail.co...
80.42.219.219
Very concise indeed! How about including a couple of graphs - one showing urban centres and the other showing temperature anomalies. I remember seeing that somewhere and it was quite striking to see that the highest rate of warming occurred away from urban centres.
2010-08-17 03:59:25
Anne-Marie Blackburn
Anne-Marie Blackburn
bioluminescence@hotmail.co...
80.42.219.219
Found the graphs I mentioned - have a look at this webpage. Any good?
2010-08-17 09:48:46
mothincarnate

wow.the.moth@gmail...
192.43.227.18
Thanks everyone - I'll work on it and updated in around 12hrs.
2010-08-18 15:42:46
mothincarnate

wow.the.moth@gmail...
192.43.227.18

Hi Graham - nice you run into you again as well. I haven't ignored your suggestion. I'm just thinking how best to add it concisely.

Cheers Anne-Marie for the link. It's a similar approach to that used by Peter Sinclair, which I've tried to mirror here in short. :)

2010-08-18 16:16:17Small suggestions...
watchingthedeniers

watchthedeniers@optusnet.com...
203.41.179.162

A very, very good start Moth. Concise, and not a great deal needs to be added.

The second image makes a powerful statement: the red zones are the Arctic, which is of course lightly populated.

Worth mentioning a cross reference to the reliability of temp records in order to address the claims of Anthony Watts et.al?

2010-08-18 16:55:48Defining UHI
gpwayne
Graham Wayne
graham@gpwayne...
86.156.59.156

Hi Tim - like the revision a lot, but it did strike me that there was some assumed knowledge - that readers would understand what UHI actually was. You could, if you thought it worthwhile, add something like this at the head:

"The Urban Heat Island effect (UHI) describes a problem with the sites where some measuring stations were located. Early sites were situated in areas that were subsequently developed, built up or changed in ways that might affect the accuracy of measurements taken. Researchers have therefore been very careful to ensure that UHI is not..." (etc).

And I think this statement needs amending:

"The Urban Heat Effect is not significantly influencing the [measurement] of global temperature trends".

2010-08-19 05:51:46Great mix of graphics and text
doug_bostrom

dbostrom@clearwire...
184.77.83.151

Horrible quibble, but the proportion of pronouns in the first paragraph bothered me. How about changing the last sentence "Likewise, they have also looked..." --> "Likewise, investigators have also looked..."

In any case "the science is sound" and I think it's ready for launch.

2010-08-19 06:33:10Good to go
Robert Way

robert_way19@hotmail...
142.162.181.139
Agreed, science is sound.
2010-08-19 12:07:00
mothincarnate

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Cheers Doug - My use of English can be a bit funny like that! :-)
2010-08-19 15:31:13
watchingthedeniers

watchthedeniers@optusnet.com...
203.41.179.162

Tiny, tiny thing - and this may be just me - but I tend not to use exclamation points unless it is for very informal posts/communications:

This is also the case with data from across China; even with the rapid growth!

To:

This is also the case with data from across China which has experienced rapid growth.

Again, that's just me. I'd also appreciate people ripping into my stuff to clean up to ensure quality control.

Cheers
Mike aka watchingthedeniers

2010-08-19 15:38:30
mothincarnate

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Good point Mike - it's more professional as well.
2010-08-19 16:17:59Sticking points
gpwayne
Graham Wayne
graham@gpwayne...
217.44.86.17

Sorry Tim - I really have to press you on both the previous points I made. You have not explained what UHI is in the first place, and the last statement is wrong. ""The Urban Heat Effect is not significantly influencing global temperature trends". UHI will never influence temperatures in any way - it is a measuring system. CO2 influences trends, not UHI, hence my suggestion:

"The Urban Heat Effect is not significantly influencing the measurement of global temperature trends".

2010-08-19 23:04:36
mothincarnate

wow.the.moth@gmail...
118.210.139.18

Hi Graham,

I've added your second part already (at the bottom - but I can include 'measurement' also).

Sorry, I've been a little distracted with a couple other events this week (even relaxing on the series part I suggested). I hope to work on it by tomorrow evening.

2010-08-20 12:22:08
mothincarnate

wow.the.moth@gmail...
192.43.227.18

Sorry about before - I thought this should be more addressing the statement, "UHI is causing the temperature anomaly," not, "what is UHI and is it effecting the temp records?"

Needless to say, it was only 100 odd words to add.

Let me know what you think :)

2010-08-20 17:22:27Typos
BaerbelW

baerbel-for-350@email...
109.41.43.59

Hi Tim,

this is what I found while reading your rebuttal:

1. paragraph

"...results in a slightly warmer envelope of air over urbanizes areas when compared to surrounding rural areas."

This should be "...urbanized areas"

2. paragraph

"..and urban China, which has experienced rapid growth in urbanisation over the past 30 years and very likely to show UHI."

Not sure, but I think something like "...and is therefore very likely to show UHI" would make this clearer (but perhaps I'm reading this wrong)

 caption for the graph:

" Jones et all" --> shouldn't that be "et al" (only one "l") as it's spelled in the 2nd line?

2010-08-20 17:25:35Good for me darling...
gpwayne
Graham Wayne
graham@gpwayne...
217.44.86.17
Hi Tim - other than the points Baerbel picked up, I think it's spot on now. Thanks for considering the changes I suggested. 
2010-08-20 17:32:31Twitter title
gpwayne
Graham Wayne
graham@gpwayne...
217.44.86.17

All - at the urging of nobody at all, I'm going to suggest some titles if I can think of any. This is a take it or leave it effort - if you like the suggestion, use it, if you don't, just ignore it. I'm just doing this because, as JC has pointed out, the Tweets are likely to draw a lot more traffic if they are engaging. I only hope I can draw the line between engaging and stupid.

Anyway, for this one:

Urban Heat Islands: serious problem or holiday destination for deniers?

2010-08-20 22:48:52Good rebuttal.
John Russell

jr@johnrussell...
84.92.176.215

Nothing major, just a couple of suggestions...

1) Rather than 'concrete structures' I suggest just 'structures' -- you go on to say 'human activity' to qualify it. As I understand it, tarmac is one of the biggest culprits suggested by deniers. 

2) 'Urbanised' (or 'z' if you're a colonial), as has been mentioned.

3) I'd prefer 'scientists' to 'researchers'. 'Researchers' sounds insufficiently scientific and can be confused with those WUWT infidels who go around taking pics of weather stations.

4)  In para 2 you write; "UHI is, of course, a real phenomenon that is the result of our activities in built up areas." Haven't you just explained that above? 

5) "The Urban Heat Effect is not significantly influencing the measurement of global temperature trends." I suggest;""The Urban Heat Effect has no sigificant influence on the record of global temperature trends." This includes a suggested rework that gets over Graham's problem with it (I think). 

Best wishes,

JR

2010-08-23 14:12:21
mothincarnate

wow.the.moth@gmail...
118.210.183.39

Cheers everyone.

I grabbed that explanation for figure one directly from the medium version - the double L is likely to be there also.

I like that title name Graham - very eye catching.

2010-08-23 15:41:20The joke
gpwayne
Graham Wayne
graham@gpwayne...
217.44.86.17
Hi Tim - glad you like it. Only thing is, if you don't mind me mentioning - the little joke probably works better without the word 'effect'. People don't go to an 'effect' for a holiday...
2010-08-23 18:04:24Gets my thmb
John Russell

jr@johnrussell...
84.92.176.215

Works well! Here's my green thumb.

Best wishes,

JR

2010-08-23 20:46:59
mothincarnate

wow.the.moth@gmail...
118.210.183.39
Good point Graham - sorry, been hit hard the last few days with the flu and am having more trouble than usual thinking!
2010-08-23 22:19:00
Anne-Marie Blackburn
Anne-Marie Blackburn
bioluminescence@hotmail.co...
212.139.81.253
Ready to go - good, informative post which is easy to follow.
2010-08-24 11:32:05
mothincarnate

wow.the.moth@gmail...
192.43.227.18
so, how do I go from here?
2010-08-24 21:16:22where to?
gpwayne
Graham Wayne
graham@gpwayne...
217.44.86.17
Hi Tim - nothing else for you to do now. John will speed it through the ether in due course, and add it to the intermediate on its own tab. Good job mate...
2010-08-29 18:44:20Another thumbs up
James Wight

jameswight@southernphone.com...
58.105.164.221
Good post. Although you do seem to repeat yourself a bit in your second and third paragraphs.
2010-08-30 09:42:52
mothincarnate

wow.the.moth@gmail...
192.43.227.18

Cheers James,

Fixed

2010-08-30 10:55:06Piling on...
Jim Meador

jimm58@gmail...
68.164.187.3
You've already got your 6 thumbs, but I feel like this is quite ready for prime time...
2010-08-30 13:49:13
mothincarnate

wow.the.moth@gmail...
192.43.227.18
lol
2010-08-31 23:11:08Published
John Cook

john@skepticalscience...
124.186.162.78
You know I'm late to the party when the rebuttal gets 8 thumbs :-)
2010-11-07 07:17:56an extra thumb for good measure.
jimalakirti

jimalakirti@gmail...
76.113.66.180
Thumbs up. I will refer to this (and link to it too) in my article (still aborning) on geothermal energy available from underneath cities as result of "urban warming".