UPDATE: We have the photo situation under control, Please don’t go to the Carefree Skyranch Airport as they’ve been getting a number of calls and visits. A follow up report is coming. – Anthony
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Since Steve Goddard and I posted recently on the subject of high temperatures in Arizona, this seemed like a good followup to problematic climate data and stations we noted in that post. In my previous post about record minimum high temperatures in Southern California I showed a map with all the new records plotted. But, there was a curious red dot record high temperature “anomaly” on it, 109°F in Carefree, AZ on July 8th:
I thought this was curious, especially since there were no other record high temps set in the state of Arizona in the last week. So, I decided to see what I could find out about the station.
My first visit was to the NCDC MMS Metadatabase to get the lat/lon of the station, plus any other info I could find:
I found the lat/lon, and an indication that it was at the Carefree Skyranch Airport, as seen from this approach photo from the airport webpage:
The photo above shows quite a bit of green for Arizona, I wasn’t sure if that was indicative of irrigation or a wet spring.
When I plugged the lat/lon of 33.8161, -111.9019 into Google Earth, it gave me the location of the NOAA weather station at Carefree airport. Right away something jumped out at me:
Check out the albedo difference due to the airport tarmac asphalt. Warmer there on sunny days possibly? I checked the weather for that day, Thursday, July 8th, and found it was full sun all day.
The red dot signifies the NCDC provided lat/lon. Note, that this was gathered (according to NCDC metadata) with a Lowrance GPS. However, the matchup isn’t always spot-on with mapping programs, plus that, since NWS has the most interest in rainfall data for hydrological forecast verifications, they take the GPS reading over the rain gauge, not the temperature sensor.
I determined that the Carefree station temperature sensor was an MMTS electronic type (on a pole) and that it had two rain gauges.
I also learned that this station was not a USHCN station, but was a Class A COOP station, and does report to the climatological database as indicated by the publish to CD note:
I also learned that the station had been converted from Stevenson Screen to MMTS in 1986:
And that apparently the observer had decided to switch observing times, but NOAA lost track of that info:
A close up aerial view from Bing Maps shows the location in detail. I was able to spot the rain gauges, but not the MMTS temperature sensor on the pole:
Interactive view available from Bing here.
The metadata from NCDC on station location, citing obstructions, shows three trees and a building nearby, all of which are visible in the image above. I’m certain the location is correct:
So what we have is a station near a building, in the middle of a sea of asphalt, in the summer in Arizona. I suppose I’m not surprised it was the lone high temperature record last week for Arizona.
Perhaps somebody who lives in Carefree or knows somebody who does can get a photo of the MMTS temperature sensor from 4 compass points and an overall view. It would be interesting to see where exactly it is located. It is a municipal airport, and it looks like the NOAA equipment is in full view of the public parking lot.
I’m betting it is near the rain gauges. Since one is a tipping bucket gauge, requiring a power cable (if it is a Fisher-Porter type with conical top) then the NWS could have killed two birds with one stone when laying cable fro the MMTS electronic sensor also.
This station data is used to adjust other nearby stations that have missing data in NOAA’s FILNET process, and since it is published on the Climatological CD, may also get used in climate studies of temperature.
I’ll check with my friend, former state California climatologist Jim Goodridge to see if he has the data on one of his CD’s from NOAA, and hopefully we’ll get some data from that station to help tell the story. Or, if anybody knows where to get it online, don’t hesitate to point it out.
Now here is where it gets interesting.
I surmised that the airport might read warmer due to the asphalt environment the temperature sensor is located in. The proof turned out to be pretty easy to find. Thanks to the many private weather stations that Weather Underground logs, I was able to locate a private station in Carefree, AZ just north of the airport and all its high resolution data for Thursday, July 8th, when the record of 109°F was tied at the airport. Here’s the tabular data showing it recording the high of 104.2°F at 3:22PM:
As indicated by the Weather Underground page, the station is a Davis Vantage Pro 2 PLUS model with the solar radiation sensor (notice the watts/m2 in the tabular data), a unit I’m very familiar with because I provide that model via my online business. I have no reason to doubt it being just as accurate if not more than the NOAA sensor. It has a similarly sized GILL radiation shield as the NOAA MMTS. It also has NIST traceable calibration for its sensors.
From the XML feed of observations provided by WU, I was also able to get the precise lat/lon of the private station, which appears to be in the observer’s back yard. I plugged the lat/lon into Google Earth and created the image below using the GE measuring tool and my paint program for annotations:
And people try to argue that airport siting of weather stations, or that siting in general, makes no difference.
You can homogenize rationalize just about anything.
I suggest that the NOAA high temperature record for July 8th, 2010 in Carefree, AZ may very well be erroneous, and a byproduct of location.
UPDATE: Commenter “Regg”, seems to think that the 129 feet elevation change between the two stations (that I didn’t think was large enough to be worth mentioning, since Google earth shows only a 10′ elevation change) could account for “most” of the 5°F difference. I considered this when I wrote the article.
Unfortunately, he’s wrong. Dry adiabatic lapse rate calculates out to about 0.7°F difference if we accept the 129′ difference in elevation between the two stations. – Anthony
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UPDATE2: We have the photo situation under control, Please don’t go to the Carefree Skyranch Airport as they’ve been getting a number of calls and visits. A follow up report is coming. – Anthony
Anthony,
You do really interesting research and this is a great website. I have a couple of basic questions:
The high temp record in question shows 109–are the sensors useful only to whole degrees or is this rounded off?
If the sensors are more sensitive, are they good to tenths, hundredths, or what?
When an average temperature is calculated, is it (high+low)/2 or are there more readings involved.
Thanks for your work–I steer as many people here as I can.
Tim
REPLY: The MMTS electronic display has an autologging high/low memory, and displays in tenths. The observer rounds to the nearest whole degree F.
Yes (high+low)/2 -Anthony
There is no “N” on the last image, but it would be interesting to note the wind direction (westerly) and see if it had the air from the tarmac upwind of the sensor.
REPLY: All images are oriented North at the top. – A
I ran the Fiesta Bowl Marathon in 1980. The race started in Carefree, which at the time was separated from Scottsdale by a good 10-15 miles. It is now part of the Phoenix Metro area – as the valley has seen massive growth.
This is how NOAA describes Phoenix
http://www.wrh.noaa.gov/psr/general/safety/heat/
So Arizona really doesn’t have such extremely hot weather? This is very surprising.
More questions, do the systems give a max/min value automatically, or is it up to the reader? I’m thinking that charting max/min times is also information about the weather, and by extension, climate. Connecting as they would to humidity, and air pressure changes.
REPLY: The MMTS electronic display has an autologging high/low memory, and displays in tenths. -A
It´s been heating up due to lawsuit against their law 🙂
Brilliant research!
This station data is used to adjust other nearby stations that have missing data in NOAA’s FILNET process
So it is manmade global warming. Manmade asphalt in Arizona. But who says asphalt isn’t natural? 😉
If you look in Google view, you will see the station out of the building area between the road and the area with buildings. (between e. craven road and the round parking).
Dought this might not be the best place, it far from what you describe. It’s in a field, about 100 feet from the closest building.
REPLY: Um, no Regg, wrong again. This is what an MMTS looks like:
http://www.erh.noaa.gov/aly/COOP/Equipment/mmts.jpg
– Anthony
@erdos, 104 degrees F is hardly mid winter in Boston. Yes it does get hot. But the question is one of data corruption with a bias towards hotter readings.
Sorry it’s east Cave Creek road (not craven road).
REPLY: Doesn’t matter, you have the wrong equipment. -A
It is extremely tempting to use airport weather data for climatology. There is normally a trained meteorological observer or high quality automated system, the recording systems are maintained, are linked to high quality communications systems and observations are carried out hourly.
However, there is a major problem with the use of airport observations METARS or extracts and summaries from them for climatological purposes. For aircraft operations there are two main factors in making a safe takeoff and landing: wind velocity and outside air temperature over the runway. Engine power is based on the ratio between input air temperature and exhaust gas temperature. If the air is hot the engine(s) will produce less power. Therefore, if there is a ‘runway heat effect’ it is THAT temperature that is required to calculate the safe freight load and take off run distances. Whereas a climatological reading would (one would hope) want to make readings that were of the ambient air temperature unaffected by any heat island effects.
In consequence, the use of airport temperatures should be avoided climatological purposes even if their use has administrative advantages.
Unfortunately, airport temperature observations appear to be the majority of the reporting stations.
The WU solar radiation graph shows a large downward spike about an hour after the high temperature. What is to be made of that? The temperature graph shows nothing simultaneous.
Dear Anthony
I think the greenery is a golf course?
Anthony, what excellent attention to detail are you like a scientist or something? What a great website!
Anthony
Excellent research which is well supported by evidence.
There is a considerable urban/bias in the GIss records which has grown up over the years and which must now be influencing the entire database.
Would you know;
How many Giss stations there are these days supplying info used in the regular official graphs?
How many of them are the same ones as were suplying information in 1970?
How many of them could now be reasonably classed as urban, but in 1970 were rural and are therefore now likely to be influenced by uhi?.
Officialdom seem to consistently fail to compare apples with apples when looking at temperature records
tonyb
I am beginning to think that wind direction and wind speed are going to be incredibly important to the resulting temperature readings. I would theorize that if the wind direction was parallel to the airport then temperature readings will be higher than if the wind direction was perpendicular. And, there must be a wind speed at which the air is able to reach maximum conduction from the asphalt and then delivers that additional radiated heat right to the temperature sensor. Are there any studies that have looked at airport temperature readings based upon wind direction and speed?
For the purpose of aviation the thermometer is perfectly placed? For the purpose of climate OR local weather it is useless. Am I correct in my reasoning?
The report above clearly demonstrates UHI effect and yet climate scientists tell us that they are able to make the necessary adjustments to tenths of a degree!!!! Then they wonder why WUWT is at the top of the pile. :o)
Any plans to look at Dell City, TX as well? I noticed on the HAMWeather map center map you show, that Dell City, TX was a red dot (high temp) in a sea of light blue (low max temp). To me, that looks even odder then Carefree, AZ did. The new high temp also beat the old record from 1994 by a full 3 degrees.
I took a quick look on Bing Maps and Dell City is an oasis of green irrigated fields. Again like Carefree it has an airport but I was unable to tell if the weather station was at the airport. The GPS location off the interactive map didn’t help. When I put Lat: 31.8 N, Lon: 105.3 W into Bing the dot was outside of town in the middle of nowhere. There was no road, two-track, building or even a tree that I could see in the area with the dot. If this is the location they may have an actual class A station!
REPLY: I knew somebody that didn’t appreciate that I stayed up late and used several hours of my life would immediately ask this question. Yes/No/Maybe -A
Another great job Anthony and is a good example of how things aren’t exactly as portrayed by the CAGW cabal. I can’t wait to she your full research report when it’s finished so that more of the truth behind the way global mean temperature is measured will be revealed.
If I still lived in Phoenix I’d get the photos you want, but it looks like you’ve got it
well defined anyway.
I lived in Phoenix for 18 years. It gets hot people. A local saying goes something like
‘it’s not seriously summer until the temp gets above 110’, which usually happens in
June. Phoenix is in a bowl so every direction out of town is ‘up’. Carefree is no
exception and has always been a little ‘cooler’ than Phoenix. What was the temp
in Phoenix that day and is there enough data to show by how much (on average) does
Carefree lag Phoenix.
Further informations.
From the NOAA station data, the station is located at 33.83°N 111.91°W with an elevation of 2401 ft. While the private station you referred is listed to be at 2530 ft. according to what the owner entered in the Wunderground database.
So that alone (the difference of elevation) can explain a good part of the delta between stations temps.
REPLY: Uh, no it can’t. If you knew anything about meteorology you’d know about the dry adiabatic lapse rate. 9.8C per kilometer of elevation. Or in this case 17.64F/km which works out to 5 1/2°F per 1,000 feet.
Since the elevation difference between stations is 129 feet according to the numbers you used, that would account for only 0.69°F out of a 5°F difference.
Here’s a handy online lapse rate calculator you can use:
http://www.ajdesigner.com/phpadiabatic/adiabatic_lapse_rate_temperature_change.php
BTW Google Earth shows a difference of 2504′ to 2514′ between the two sites. – Anthony
The ‘green’ in the pictures are primarily golf courses. Carefree is a high end residential
area with lots of retirement amenities.
I like the map with the record dots in the OP. Looking at all the lower 48 states is even better: http://mapcenter.hamweather.com/records/7day/us.html?c=maxtemp,mintemp,lowmax,highmin,snow
For some unfathomable reason looking at it makes me think of Newton’s Third Law of Motion commonly known as for every action there is an equal and opposite reaction.
I had puzzled over that red dot in the previous post, too.
It’s clear to me that the global weather data is only loosely related to reality, but I’m still wondering why Carefree chose that particular occasion to have a record high; the sun often shines in Arizona, after all and they don’t only unroll the pavement for special occasions. With the general coolness all around, there should be a very idiosyncratic reason for this local exception; a truck idling e.g.
My own experience with sensors of different types leads me to believe that they are all gremlin hang-outs, and I know that sounds silly but it’s better than saying they have a mind of their own.