The UHI's of Texas are upon you

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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@Joe D’Aleo
> Thus, it is not surprising to see that the state of Texas has very
> little trend while Texas cities have a significantly greater trend.
So, Joe, 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. But you disagree, quantitatively, on how those increases are distributed?
REPLY: Joe didn’t write that, I did. I disagree with the way the data is homogenized, combining the good stations with the bad ones for a smeared around data result that is claimed to be representative – Anthony

mkelly

In the 1970’s oil shock the idea of “thermal mass” for storing energy/heat was talked about a great deal. Cities by their very existance have thermal mass. Black top roads and concrete buildings who would have thought they can get hotter than grass and trees. Ever listen to an announcer tell you the temperature on a baseball field at stadiums with artificial turf?

tadchem

The other side of the coin is the data from sites NOT in/near UHIs. In Texas this would mean sites not near the cities listed above, those with about 200,000 or more population. What do the temperature data show for these sites?

More data to back up E M Smith’s great work, and suggest to Steve Mosher that although his sums are fine, his parameters need re-examination perhaps.
And of course, a whole pageful of UHI studies here. I shall now add Anthony’s excellent study here to that page as soon as I get a chance – and as soon as I can cope better with my own arm RSI. Thank you again Anthony for keeping this important issue up front. Hope your own hand healing process is being protected from further strain.

This post goes to the heart of my argument: the inconsistency of CO2-caused warming. If little warming is shown state-wide, yet the big cities are rapidly warming, then many places must be cooling.
Why does CO2 allow those non-urban areas to cool?
See http://sowellslawblog.blogspot.com/2012/05/warmists-are-wrong-cooling-is-coming.html
And the portion following:
“This is from Abilene, Texas which is right out in the middle of the state, a little bit west of Dallas.  It shows absolutely no warming whatsoever for the past 110 years or so. The slope here, and you probably cannot read that, is actually negative. It is -0.19° per century, round it off -0.2. From an earlier slide [Figure 1], remember we were looking at a warming trend  of about 0.6° per century, which is what the warmists are saying. I want to know why it ignored Abilene?”

Kristen Byrnes (Ponder the Maunder) — 1
Al Gore (Post Turtle) — 0

Earle Williams

It’s official, CO2 causes *extreme* population growth.
😉

Disputin

Like Tadchem, I reckon that if all major cities show a greater temperature rise than the State as a whole, then rural areas must show a decline. The only way to display global temperatures is to eliminate all urban sites. That blows AGW out of the water.

Marcos

with TX cities, you also have to consider the huge amount of growth in the suburbs outside the city limits. the last 15 years has seen a large influx of people to the states major metro areas. in Houston, you can see where large areas, 20-30 miles out from the city, that used to be woods in the 90’s are now parking lots, subdivisions and strip malls…

Old England

Without looking at the data – is it that in rural areas that temperature has shown little or no change and that ‘adjustments’ for UHI are far, far less than the recorded amount of change when compared to rural temperatures thus leading to the deceptive appearance that Texas has seen a rise in temperature ?
Be interesting to see unadjusted average temperatures of the rural areas plotted against the same in urban areas to see how far off the ‘adjustments’ for UHI are in Tx.

KTWO

The trend may look flat. But just wait until the past gets cooler.

Nick in vancouver

Take the data from the top cities out and see what happens for the rest of the state.

Neo

Perhaps there are better ways to handle UHI that are better than a simple across the board CO2 type tax

AnonyMoose

John Day: ” ‘man-made activities’ (i.e. urban heat islands) have created measurable increases in Texas temperatures over the past century”
Don’t confuse temperatures of Texas cities with temperatures of the state of Texas. Just because the roof of your house is very hot does not mean that your backyard is the same temperature.

Jim G

KTWO says:
June 28, 2012 at 11:12 am
“The trend may look flat. But just wait until the past gets cooler.”
As I noted in another post, even the Weather Channel had a brief item last night re the UHI phenomina though, at least in the part I saw, did not relate it back to the mismeasurement of overall temperatures. The past may not get cooler in the UHI areas as concrete and roof areas increase over time.

Curiousgeorge

Somewhat OT, but the SCOTUS ruling on the AHCA today dealt a blow to using the Commerce Clause indiscriminately. This will have widespread ramifications on various regulatory agencies who rely on it as their legal right to regulate many things. Including issues related to food, farming, water, etc. We’ll have to wait and see, but I think it will be of benefit in reining in the EPA, USDA, and others.

Of course, you know that the UHI effect can be seen as evidenced in the higher-res IR satellite imagery for some of these cities (like Dallas) as evening turns into night and radiative cooling takes place in the countryside …
.

This is pretty good data as it puts a few myths to rest.
1. Most studies of UHI ( like Oke ) focus on UHI MAX. that is the maximum UHI that
a city can see. To do this researchers cherry pick the days to study. They study
days that have the optimal synoptic conditions for UHI: no wind, no clouds, no precipitation
in the previous days leading up to the observation. This is all well and good for capturing
the maximum, and you will see figures like 2C, 4C, and higher. But this is not average
UHI. Average UHI is what biases the record so we need a good estimate of the average
which means we need to look over time.
2. Its unfortunate that the data was presented in F. But we can fix that. First thing we have to note is what the literature already shows for a range of UHI Bias. Now most of this
is for large cities, but generally the bias is anywhere between .05C per decade to .125C
per decade for cities and regions such as : large US cities, tiawan, korea, china, japan,
and London.
What do we find in texas for 1948 through present, a baseline trend of .1F decade
for a quick and dirty estimate of the UHI bias added above this trend we have
Dallas: UHi ads approx .1C per decade
Houston: around .05C
Corpus Cristi : < .03C decade
San antonio: .15C per decade
El Paso and amerillo.. lost in the noise.
With the exception of San Antonio all are within previous estimates. It would be interesting
for example, to see what happens to the average in texas ( and the world) if you remove
all cities larger than 10,000. Another way to look at it is this. If we make one pile
of all the stations that have tiny populations ( less than 10 people/sq km ) and
another pile of all the other stations ( on average 500 people per sq km).. the UHI
Bias is on the order of .04C per decade. ( Hausfather & Mosher)
As a side note population density in places like dallas and san antonio is on the
order of several thousands per sq mile ( and 1-3 thousand per sq km ) far above the
average of all stations.
The other things we see of course is that other factors ( such as distance from coast )
can really drive UHI. For the global database, therefore its good to remember that a good majority of human population lives on the coast in coastal cities. consequently in the global database its important to realize that the total effect of UHI can be muted by city location.
the more cities in your database that are on the coast the lower your UHI bias.
The other really important factor here is that UHI is also known to be much higher in northern latitudes than in southern latitudes. Texas is a northern latitude location.
An one last thing to note is that while a "log" curve is a good approximation for
UHI MAX for large cities, the data here ( UHI average ) indicates, as does other research,
that average UHI is not easily modelled as a function of population. Oke himself realized this and modified his formula to take regional windspeed into account as well as the regional building practice. Large population in high rises exhibit the highest UHI whereas large populations spread out in sprawling cities have lower UHI. Basically building height matters ( statistically it matters more than other factors ) Specicially aspect ratio matters.
( compare the aspect ratios of dallas and san antonio for example) and its also clear why san antonio would tend to have the higher UHI
Finally, all of these cities are large population. you dont see any "village UHI" here and what the data seems to indicate ( if you plot UHI versus change in population ) is that the bias
vanishes as you go to smaller and smaller populations.
As an example: in the Berkeley Earth dataset, around 10000 stations have zero population.
You can in fact build a global database where there are no large cities, no medium sized cities, no small cities,..

MarkW

“So, Joe, 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. But you disagree, quantitatively, on how those increases are distributed?”
Man caused, yes.
CO2 caused, no.
So controlling CO2 is the wrong solution for this problem.

SocialBlunder

Good vs. Bad stations? There are a bunch of people in these rapidly growing cities that care about how hot it is in those cities. Temperature measurements in those cities are valid for those cities for many purposes – not just dithering about global warming. To exclude temperatures from where millions of people live because millions of people live there seems a little absurd.
In arguing for a UHI, this article compares absolute temperature records when temperature anomoly records are used to determine GW.
Why are you using absolute temperature instead of temperature anomoly? Here is NOAA’s explanation of why anomoly is superior: http://www.ncdc.noaa.gov/cmb-faq/anomalies.php go to question 7.
It would be very interesting to discuss why NOAA’s methodology does not account for UHI. Here is how they address it: http://www.ncdc.noaa.gov/oa/climate/research/ushcn/#urbanization

Josh C

Intersting, I just moved to Corpus Christi – With so much air moving in the city from the ocean, you can see while driving the change in temperature as you drive through the town, but it isn’t much.
Driving into San Antonio, your A/C sound will change, it is almost a line you cross. The town is significantly hotter from outside the city limits compared to inside. You can feel the difference.

MarkW

0 population doesn’t mean no UHI. Airports don’t have any population.

What seems to be missing in the discussion of UHI is that it is not just a factor of population. The radical increase in air conditioning and use of asphalt in the 1965-1985 time slot (for the US at least) would give a much larger anomaly jump during those years. Any study that looks at a different time period to calculate an average UHI would miss this.

John West

SocialBlunder says:
“To exclude temperatures from where millions of people live because millions of people live there seems a little absurd.”
What’s absurd is taking a temperature (absolute or anomaly) increase that has been artificially increased due to population increase and attributing that increase to “enhanced greenhouse effect”; excluding those temperatures is the exact opposite of absurd.

There are other local factors at play in addition to population. As this map that Muller produced shows, there are many stations with warming trends next door to ones with cooling.
Simply averaging them all together is nonsense.
http://notalotofpeopleknowthat.wordpress.com/2011/10/22/kansas-temperature-trend-updatemuller-confirms-there-is-a-problem/

wayne

This is Oklahoma 1895-2012 and right now, just about to tick a very normal 100F, I can’t wait for a little of that long-term cooling in the fall !! Global warming, right, and pigs fly… I’ll deny both.
http://i46.tinypic.com/2dvu88l.png

@AnonyMoose

John Day: ” ‘man-made activities’ (i.e. urban heat islands) have created measurable increases in Texas temperatures over the past century”
Don’t confuse temperatures of Texas cities with temperatures of the state of Texas. Just because the roof of your house is very hot does not mean that your backyard is the same temperature.

You’re missing the point I was making about the ‘qualitative’ impact of UHI.
For example, do you agree, qualitatively, that the “hot roof” of my house increases mean temperature of my property (where PROPERTY=HOUSE+YARD)? Yes or no?
(Does one child, with a fever, increase the average temperature of a classroom of children?)
If ‘yes’ then we can argue, quantitatively, how to obtain an unbiased estimate of that increase.
So it’s all about the ‘weighting factors’, right?
But having said that, I also happen to believe that surface temperature is only one factor in computing the Earth’s radiative balance. Others include clouds, oceans, convection and heat/cooling induced by evaporation/condensation etc.
😐

Gail Combs

KTWO says:
June 28, 2012 at 11:12 am
“The trend may look flat. But just wait until the past gets cooler.”
________________
Jim G says:
June 28, 2012 at 11:44 am
….. The past may not get cooler in the UHI areas as concrete and roof areas increase over time.
___________________
AHA, but the past DOES get cooler at least if Hansen controls the data Hansen’s 3 GRAPH Set

SocialBlunder

JW: Attributing UHI warming to GHG is absurd. Excluding temperature readings would be cherry-picking (absurd if you want to be taken seriously – especially by someone who lives in San Antonio). 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?

KTWO

Gail. I was indeed referring to how the past seems negotiable and plastic. Then I was astonished when Jim G. seemed to take my cooling comment seriously. That seemed so unlikely I thought he was responding in a clever way I did not grasp..

Elmer

The Amarillo airport is on the far east side of the city while most of the growth for the last several years has been to the southwest. No surprise the thermometer has not sensed any UHI.

Dan Johnston

Anthony
If you run a linear regression on the decadal temperature increases vs the current population, excluding Houston and Corpus Christi due to the oceanic moderation effects, you get a correlation coefficient (R2) of 0.862 which seems to indicate that population and population growth (Duh!) are affecting temperatures significantly. Although there are only 4 points for comparison due to lack of data, I’m sure if you did a comprehensive analysis using population growth change since 1948 for all of the cities in your list you would derive an even stronger, more robust relationship. This effect cannot be anything other than UHI and including this type of data when looking at climate change can only be considered an “harmless” way of proving that global warming is out there ready to destroy us all without letting truth or facts or common sense get in the way.

Another ‘problematic’ temperature data set?
‘Voice’ of the supersonic solar wind from a coronal hole:
Ev’ry June night I’ve been huggin’
The Earth’s magnetosphere like pillow
Dreamin’ dreams of Amarillo
I’ve been breezin’ like a willow
To warm sweet Marie in Amarillo.

http://www.vukcevic.talktalk.net/A-E.htm

Jim

Yeah, I wonder if these hot temperatures today should even count. It hasn’t rained in a long time. I was just out and the ground is parched… I bet the surface temperature is like 120 or higher, even over the grass which is all dried out and no longer transpiring any moisture. It’s basically like the weather stations are reading over cement or asphalt given how hot the ground is… so these records are questionable. The sensors need to be at least 30′ above the surface to avoid the effects of thermal radiation off the ground.

more soylent green!

Roger Sowell says:
June 28, 2012 at 10:40 am
This post goes to the heart of my argument: the inconsistency of CO2-caused warming. If little warming is shown state-wide, yet the big cities are rapidly warming, then many places must be cooling.

Bingo!

Mindbuilder

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?

George E. Smith;

Looking at your State of Texas for last 100 with it’s black average and green trend, prompts the following question :-
What would be the value for the very next future point on this graph, that would convert the green trend line exactly into the black flat line ?
Enquiring minds want to know !!

EternalOptimist

weighting factors, anomalies and statistical tricks.
There used to be a saying that a soldier wearing a steel helmet was always marching south. If anything artificial is affecting the instrument then either it, or the instrument should be removed.
If you leave the helmet on, take the reading and then try to compensate, you will get lost

Paul Deacon

Anthony – I suggest it would be nice to see on the same page some graphs for rural stations.
All the best.

Mindbuilder, here is an explanation:
“A new index of calculating the intensity of urban heat island effects (UHI) for a city using satellite skin temperature and land cover observations is recommended.
UHI, the temperature difference between urban and rural regions, is traditionally identified from the 2-m surface air temperatures (i.e., the screen-level temperature, T2m) measured at a pair of weather stations sited in urban and rural locations, respectively.
However, such screen-level UHI is affected by location, distance, and geographic conditions of the pair of weather stations. For example, choosing a different pair of rural and city sites leads to a different UHI intensity for the same city, due to the high heterogeneity of the urban surface temperature.
To avoid such uncertainty, satellite-observed surface skin temperature measurements (i.e., skin level, Tskin) is recommended to record UHI, known as skin-level UHI or UHIskin. ”
http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-11-00509.1

@more soylent green, EXACTLY!
In fact, the NCDC data base for 48 Contiguous states shows 8 states with cooling trends and three with zero trend. Yet we know these states contain cities with rapid warming trends.
Therefore, CO2 is not getting the job done in the cooling sites. Can physics act arbitrarily? Capriciously?
I think not.
See the Figure 1 at:
http://sowellslawblog.blogspot.com/2011/09/us-long-term-temperature-trend-from.html

SocialBlunder said (June 28, 2012 at 11:58 am)
“…In arguing for a UHI, this article compares absolute temperature records when temperature anomoly records are used to determine GW.
Why are you using absolute temperature instead of temperature anomoly?…”
Anomalies are bad because they use a time in the past as their reference (GISS, for example uses the oldest reference period – 1951-1980). If the effect from UHI was less around 60 years ago, then naturally any current “warming” (about 1 degree or so) would show up.
Using raw data shows how much of that anomaly rise can be attributed to UHI, and how much to data processing.

George E. Smith;

Another question for population enhanced UHI. Just how much is contributed to the UHI increase of a hot populated place such as Houston for example, by the effect of having everybody in such a town, being inside of an air conditioned enclosure, which is internally cooled down to the common chilly AC optimum temperature like 60 deg F thereby putting all that extra heat outside the buildings to add some positive AC feedback to the solar heating of the outdoors ?
Just asking !

P.F.

For me, what all of these graphs reinforce is the cherry picking of the recent data sets used to promote the sustainably schemes to solve global warming. Notice how the late 1970s lows can be used to create a strong statistical upward trend going into the 2000s. All of the hog swallow I’ve seen lately justifying the Climate Action Plans start their data in the 1970s with a complete disregard for the previous 70 years of data that flatten the historical curve.

paddylol

S Mosher, when evaluating data from 10,000 stations with 0 population, how do you deal with features that influence temperature, including location, elevation, topography,average precipitation,and influences from maritime, riparian and lake effects, etc?

u.k. (us)

It is about 100 degrees in Chicago right now, and it feels like it.
What happened to the time, when you went thru days like today, with the feeling that you have survived the worst She can throw at you, and have lived to spread stories of the hellishness of it all.
I wonder.

BILL KURDZIEL

Anthony,
Reviewing the excellent post of Joe D’Aleo on the Urban Heat Island effect in Texas makes me wonder again how the raw data is “adjusted” when entered into global averages. I’ve made up some hypothetical city data and their average temperatures by year, as follows:
SAC DAVIS YOLO
1960 80 80 80
1970 81 80 80
1980 82 81 80
1990 83 81 80
2000 84 81 80
2010 85 81 80
SAC is a fast growing metropolis, DAVIS is a bedroom village 20 miles away, and YOLO is a slowly growing ag town 50 miles away. SAC qualifies as a Heat Island. Assume all three locations are included in the global averages. Without getting into the mathematics used in the adjustments, can you, in a general way, show what the adjusted temperatures might be for each of these cities when entered into the global mix?
Many Thanks,
Bill Kurdziel

MarkW

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.

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.

Bryan A

Interesting to note that in the first graph for the entire state there appears to be an 80 year heating & cooling cycle and, further, that many of the individual city polts also indicate a similar cycle with both warmer and cooler phases.