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.
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
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.
😐
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
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?
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..
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.
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
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.
Bingo!
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?
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 !!
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
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.
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 !
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.
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?
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.
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
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.
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.