Joe D’Aleo suggested earlier today that I take a look at some of the data from NCDC’s web page called “US climate at a glance“. This page allows comparisons of the actual data not anomalies used in the NCDC USHCN Surface temperature network. The NCDC web page allows you to compare and not only the nation but states and cities as well using the actual USHCN data. Joe’s interest was the urban heat island effect (UHI) in cities in Texas. First let’s take a look at the state of Texas itself for the last 100 years:
Source: http://www.ncdc.noaa.gov/oa/climate/research/cag3/tx.html
As you can see the trend is essentially flat, with the trend equaling 0.01F Per decade over the last 100 years. That trend by itself is interesting, but there’s a lot more of interest when you look at the cities individually.
Here is a list of cities in Texas based on population size, this table is from Wikipedia:
| Rank | Population | Place name |
|---|---|---|
| 1 | 2,099,451 | Houston |
| 2 | 1,327,407 | San Antonio |
| 3 | 1,197,816 | Dallas |
| 4 | 790,390 | Austin |
| 5 | 741,206 | Fort Worth |
| 6 | 649,121 | El Paso |
| 7 | 365,438 | Arlington |
| 8 | 305,215 | Corpus Christi |
| 9 | 259,841 | Plano |
| 10 | 236,091 | Laredo |
| 11 | 229,573 | Lubbock |
| 12 | 226,876 | Garland |
| 13 | 216,290 | Irving |
| 14 | 190,695 | Amarillo |
The third largest city in Texas by population is of course Dallas. Unfortunately, Dallas only has data going back to 1948 according to the NCDC pages that allow selection. So will use 1948 as a starting point for comparison, here then is the statewide trend since 1948:
The Decadal scale trend from 1948 to 2011 is 10 times larger than that of the last 100 years at 0.10 Fahrenheit per decade.
Now let’s look at major cities in Texas available from the NCDC cities page, first Dallas:
Source: http://www.ncdc.noaa.gov/oa/climate/research/cag3/city.html
The decadal-scale trend in Dallas is almost three times larger than that of the state of Texas at 0.28 Fahrenheit per decade.
Now let’s have a look at the largest city in Texas, Houston:
Being the largest city, one might expect that Houston would have a larger trend than Dallas, however it should be noted that Houston has a strong ocean influence from the Gulf of Mexico. So, one would expect that it’s trend would be muted compared to an inland city.
Corpus Christi is another Texas city that has an ocean influence. It’s decadal-scale trend is also somewhat muted by comparison:
It is also a significantly smaller city with less growth:
San Antonio however being the second largest city is well inland away from the ocean – look at its trend:
At 0.41 Fahrenheit per decade, it is four times larger than the statewide trend from 1948 to 2011. The population of San Antonio looks like a hockey stick, especially after 1940:
According to the Wikipedia entry on San Antonio: “It was the fastest growing of the top 10 largest cities in the United States from 2000-2010, and the second from 1990-2000.”. So I suppose it is no surprise to find it having such a large temperature trend compared to other Texas cities and the state itself.
El Paso, TX:
Like Corpus Christi, El Paso didn’t grow quickly either.
Amarillo:
Amarillo didn’t see wild growth like San Antonio.
So what can we conclude from all of these comparisons? First, I’d like to point out that this is not a definitive comparison, as it is lacking many of the cities in Texas but these are the cities that were available from the NCDC page.
But, what we can conclude with certainty is that all of the (available) cities plotted from NCDC Data at “US climate at a glance” show a decadal-scale trend that is larger than the decadal-scale trend for entire state of Texas for the same period. Of course, Texas being composed of wide open range has many USHCN stations that are not in populated areas. Thus, it is not surprising to see that the state of Texas has very little trend while Texas cities have a significantly greater trend.
Dr. Roy Spencer has found more UHI examples in Roy Spencer’s ISH population adjusted discoveries. He writes:
The bottom line is that there is still clear evidence of an urban heat island effect on temperature trends in the U.S. surface station network. Now, I should point out that most of these are not co-op stations, but National Weather Service and FAA stations. How these results might compare to the GHCN network of stations used by NOAA for climate monitoring over the U.SA., I have no idea at this point.
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I’d add. What we are seeing is the Weekend Effect on a multi-decadal timescale.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC208739/
There used to be a good wikipedia page on the Weekend Effect, but its been dissapeared.
Mindbuilder says:
June 28, 2012 at 1:00 pm
Has everyone here forgoten Anthony’s surface stations project and study. He found that recorded urban temperatures are a little COOLER during the hottest part of the day and a little warmer at night than well sited rural stations! But they average very close to the same. How can this Texas info be rectified with Anthony’s study? Is it just cherry picking?
Anthony, are you going to do any more analysis to explain the perplexing results of your UHI study? Did the climate scientists dump cool rural stations? Did they move the urban stations to irrigated lawns? Do urban stations use cooler instrument designs, or what?
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The answers (including some you have yet to ask) are in the pipeline, awaiting release.
I suspect UHI has a greater effect than just temperature. As a very long time windsurfer, I’ve noticed changes in wind patterns around Sydney, Australia. An afternoon summer NNE sea breeze blows at typically 20 knots, 30 Km N of Sydney. However it now blows just 5-10 knots up to 10 Km N. Conversely, up to 5 Km S it blows 30 knots.
SocialBlunder says:
”Adjusting for the effect of UHI in the temperature record seems like the best way to go – which is why it would be so interesting to understand whether and why you believe the adjustments were done incorrectly. Can you explain why NOAA’s approac is inadequate?”
Why would adjusting for UHI by excluding temperature readings affected most by UHI be cherry picking? IMO, not excluding them is cherry-picking. I’m not saying NOAA’s approach is necessarily inadequate, but that it is an overly complicated solution to a simple problem.
The problem: UHI effect – Solution: exclude UHI affected readings. OR Problem: UHI effect – Solution: Run raw data through a complicated mathematical procedure to eliminate UHI effect.
Analogy:
Problem: In Los Angeles need to be in Las Vegas Solution: Drive to Las Vegas OR Problem: In Los Angeles need to be in Las Vegas Solution: Fly to NY, drive to Chicago, fly to Miami, drive to Atlanta, and fly to Phoenix, bike to Las Vegas.
Both solutions get you to Las Vegas, but one is better. (Hint: KISS)
On the other point, I don’t see how whether where one lives is or is not included in the calculation of global average temperature matters one iota.
For most of the states in the Union there is a correlation between the population around the stations and the temperature they record, in a log relationship, when TOBS temps are used. (Populations can now be found on the web). But, for Texas, this relationship does not have as high an R^2 value as do many of the other states. The plot (among others) is found on Bit Tooth Energy
I’ve been watching the BBC’s weather page over the last few months which has a list of ‘Hotspots’. Heathrow has been top of the list (by quite a few degrees) for days on end while the rest of us are damp and well below average for the time of year. I suspect that is purely due to it being a very busy airport and nothing more, I wonder where the temperature stations are at Heathrow because something isnt right with the recorded temperatures.
Not sure the urban temperature here is ‘cooler’ than that just outside the city here during our (right now in Texas! showing 105 on 3 different thermos) hottest part of the day … not born out on IR satellite image ATTM either, although the granularity of the scale (5C per step) may be obscuring differences … at night significant differences on satellite DO show up however. Practical experience (driving w/o air conditioning) does indicate that is is COOLER outside the city/urban areas; at 3 PM local try putting your hand down on concrete or an asphalt roof shingle vs a green pasture or grass …
One may look for oneself; this page will allow you to go back to the nighttime hours and and back as far as a week as well:
http://weather.rap.ucar.edu/satellite/
.
Philip Bradley says:
June 28, 2012 at 2:09 pm
The trend reversal in 1976 is very clear in those urban temperatures.
What happened?
Answer: the catalytic converter was mandated on all new petrol vehicles in 1975. One thing all urban areas have in common is a lot of cars.
Not to mention the heat from modern onboard electronics.
@ur momisugly MarkW says:
June 28, 2012 at 2:01 pm
Curiousgeorge says:
June 28, 2012 at 11:47 am
The ruling did declare that you can’t use the Commerce Clause to justify anything, but at the same time it also declared that you can force people to do anything congress wants by using congress’s power of taxation.
In other words, there is no limit to congress’s power to run our lives, they just used a different part of the constitution to justify the new powers.
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That may be true, however the ruling should make it more difficult. People have a natural aversion to taxation. If it applies retroactively to existing regulatory justifications, then that opens the door for rewrites and potential retraction of many regulations.
Philip Bradley says:
June 28, 2012 at 2:09 pm
Cats don’t work well until they’re up to the right temperature. In the UK at least, that excludes most journeys because they are under 60 miles. Last I looked, that’s how long it takes for a cat to start working. That’s why the Rover group favoured the “lean burn” engine.
DaveE.
John Day says:
“…would it be fair to say that you agree, qualitatively, with the AGW crowd that ‘man-made activities’ (i.e. urban heat islands) have created measurable increases in Texas temperatures over the past century?”
Certainly. If you agree that urban heat islands and their resulting measurable increases in Texas temperatures have absolutely nothing to do with increases in CO2.
In the USA, vehicle pollutants peaked mid-1970s and have steadily declined since. Although the decline in NOx has been small.
See figure ES-1
http://www.epa.gov/ttn/chief/trends/trends98/trends98.pdf
It’d be interesting to see how the temperature has changed in towns with little or no population growth that are located near these cities listed above.
Neo says:
Perhaps there are better ways to handle UHI that are better than a simple across the board CO2 type tax
Hmmm… so a city population tax? Live in a big city, pay through the nose for the privilege.
Sounds like a good idea to me.
The key is not state by state, but ENSO geographic area by ENSO geographic area. State lines are arbitrary and the jet stream/atmospheric pressure systems care not one wit for state lines.
I beg to differ; ever notice that sweet smell that emanates from a just-started engine? I don’t think those are raw hydrocarbons (at least none like I’ve ever smelled, and my non-cat 1500W generator still emits plenty of CO and unburned fuel on start-up which smells pretty much like it always did so it isn’t the change in fuel over the years …)
They may work better warmed-up; but that is not in contention …
.
Putting my stupid warmist hat on for a moment,.. I would blame UHI on the fact that more people using more SUV’s = more CO2 = higher temperatures. Easy. Next?
/sarc…
Pamela Gray says:
June 28, 2012 at 5:15 pm
The key is not state by state, but ENSO geographic area by ENSO geographic area. State lines are arbitrary and the jet stream/atmospheric pressure systems care not one wit for state lines.
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Yep. I feel the same way when data is expressed by decades.
Nature, if it has a clock, runs on a different scale.
Anthony, clever turn of phrase on the title! (for those not acquainted, the State Song is ‘The Eyes of Texas Are Upon You’. I love tweaking UT folk by calling it the ‘I’ve been working on the railroad’ song, as it’s the same tune and it’s UT’s school song.
“How these results might compare to the GHCN network of stations used by NOAA for climate monitoring over the U.SA., I have no idea at this point.”
There is an interactive map here which shows unadjusted GHCN trends for 1951-2010, 1966-2010 and 1981-2010. It’s a map colored by trend; you can focus on Texas and display and click on stations to get numerical data. For 1951-2010 there is a general warming trend along the coast and a band of cooling in the interior.
@Louis Hooffstetter
Agreed, of course. I don’t think anybody, including the AGW crowd, claims that UHI is caused by CO2.
In fact, it’s the AGW crowd who tend to deny that UHI has any significant effect on global surface temps. So I guess I could call them “deniers”. But I won’t.
😐
Nick Stokes says: “unadjusted GHCN trends for 1951-2010, 1966-2010 and 1981-2010.”
Why not for longer periods? Would it not be most interesting to compare with the official NCDC record for the full period?
The first graph shows steps. You shouldn’t use OSLanalysis.
For those mentioning the inflection point ~1976, keep in mind we have several potential cycles and forcing agents at play in looking at temperature trends, including AGW (which I think is quite small), UHI, and various natural cycles such as the PDO. In 1977 the PDO switched from negative/cool to positive/warm. The temperature trends in southwestern states (away from heavy urban influences) generally reflect a PDO cycle over the period of the trend analysis in this post. When one does a trend analysis over a period of say 1948 to 2011, this happens to overlay one complete PDO cycle from the start of the negative phase in the late 1940s, to the approximate the end of the positive phase (NASA said PDO went back to negative in ~2007, if I recall correctly).
The temperature contours for the lows http://www.aerology.com/?location=Usa&mapType=Tmin&date=6%2F28%2F2012
and the highs show the UHI as well as natural differences in temperatures across short distances
http://www.aerology.com/?location=Usa&mapType=Tmax&date=6%2F28%2F2012
there are some cities that don’t seem to have heat signatures, like St Louis Mo.
And if it is not the fact that most of the wheat has been cut and the pastures grazed down by now, and mostly forests north of the line, what is with the shift across the USA Canada border?
http://www.aerology.com/?location=NorthAmerica&mapType=Tmax&date=6%2F28%2F2012