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
gotta love this . an internet thread with a discussion of wet & dry adiabatic lapse rates . . . . never imagined that would happen when I took my climatology courses waaaaay back when.
tallbloke says:
UAH and Hadley Met agree so closely on the 30 year trend is indicative that Hadley probably don’t deserve to be tarred with the same brush as the CRU crew.
Having thought about this a bit more I’m not so sure. Wouldn’t we expect the troposphere to warm more than the ocean surface, given the differing heat capacities of water and atmosphere? See how much the tropospheric temp rose compared to the ssts during the 98 and 09 el ninos.
Hmmm?
Before you spend a lot of time investigating this, I have noticed exactly the same sort of issue before in practically every region of the country. I have often noticed a “record high” pop up in an area of either record low temperatures or record low high temps on this same map. Sometimes I would find a temperature that is 20 or 30 degrees warmer than any other station around it. This might be in Tennessee or Wyoming or anywhere (not just a desert area) and it can be in any area of the country. Note that I have not yet found an error in the opposite direction. I have never noticed a record low in an area surrounded by record high temperatures or record high low temps.
It simply seems that anomalously high temperatures simply pop up in the data from time to time. For example, on December 5, 2009 I found a “record high temperature” in the 70’s for Samburg, TN. I looked at surrounding stations and none were over 40F that day. I then found another one in Pavillion, Wy on December 2, 2009 that claimed a temperature of 61F when I couldn’t find anything around it higher than 20F that day.
So it would seem as if random “record high” temperatures simply get plugged into the data for some reason.
But it is a dry heat.
Can’t trust the thermometers. It is better to stick with a hunch and homogenized data.
Note according to this link, the temperature for Samburg, TN is still on the books even though it is CLEARLY an error.
There’s your Global Warming. Hansen and asphalt, and nothing more.
Assuming you can get the data for the coop station from somebody with the CD,
a long term comparison with the weatherunderground data would be interesting to say the least.
Might be interesting to approach WE about compiling downloadable history files..
The Pavillion, WY record is still on the books, too. That one is a good 40F higher than surrounding stations for that day. I would say both the one in TN and the one in WY are impossibly high temperatures for the day yet they remain on the books nearly 8 months later. I pointed them out at the time and never really got a response other than:
from:
Lee Huffman
HAMweather, LLC a WeatherNation Company
Who produces those maps.
Just need to write a program to scrape this
http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=KAZCAREF2&month=1&day=1&year=2007
looping over month and day and year until the present. some straightforward processing and you can get monthly means.. 3.5 years of data.. neat project
if anybody is inclined
Sorry. here is the url to scrape
http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=KAZCAREF2&month=1&day=1&year=2007&format=1
Maybe, I’ll post up some R to do part of this later
Anthony
I think this Regg is probably the same Regg that blurts out loads of rubbish at AGW sites and also on skeptic sites in particaular Accuweather. I have never seen him make anything other than ill considered statements. Le pauvre;
Thanks for work Anthony. I don’t know where you and Steve Mc find the hours in the day.
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Regg says:
July 12, 2010 at 6:28 am
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.
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No, not even close, if the elevation difference is only 129 ft. Report back when you have looked up the correct relation between altitude and temp.
Gail Combs says:
July 12, 2010 at 8:44 am
It’s nice that not all new ideas or data are greeted dismissively! Maybe geologists have learned the lesson.
Gail Combs says:
July 12, 2010 at 9:02 am
Karl Maki says:
July 12, 2010 at 8:27 am
I live in Scottsdale (about 20 miles from that airport) and have been in that area recently….
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Any chance you can get Anthony his photos, or at least a verbal report on that site and the private site some time soon?
I’ll try to make it up there. In the meantime, I’ve left a message with the Carefree construction coordinator to see if I can get any info on what might have been happening on the road in front of the airport last Thursday.
Bill Tuttle says:
July 12, 2010 at 8:45 am
Hi Bill. Thanks for the information…nice to learn some more detail on this. I remember the 3 degree number from my college geography class about 6 years ago…couldn’t remember if it was 3 F or 3 C. For the calculation, I assumed 3 C since that would cut Regg the most slack…by the time my calcs got posted, though, several others had already posted on it, some with better detail than myself.
Thanks again,
-Scott
It could be a Lamp post but it looks like a temp sensor at 33.81685, -111.90204 just east of the tree
There is not anymore fuel for more hurricanes this season:
http://weather.unisys.com/surface/sst_anom.gif
Also note that the source of these apparently random errors in NOAA record data are not apparently due to the METAR sign problem as that both the correct and incorrect data are often of the same sign in degrees C. This is just plain incorrect data, sometimes by margins much larger than 5F and often tens of degrees. But why it is always high and I have never spotted one 30 degrees low baffles me.
From the looks of things, Regg found the old Stevenson box, not the current MMTS sensor. None of the Google Earth images provided so far show the familiar, white, stack o’ doughnuts shape of a MMTS sensor pod.
REPLY: Its not even that. – Anthony
[FURTHER REPLY – Definitely not. There are two box-type objects that show up. Street-level shows the one to the west is clearly nothing to do with climate equipment and the other is shown (by photos) definitely NOT to be a Stevenson Screen. It may be (or not) the power source for the rain gauge that folks have been misidentifying (via Google Earth and Yahoo street view) as an MMTS. We are now informed that the Stevenson Screen was removed in 1986. Not to dis Regg, though: it was definitely a spot to consider closely. ~ Evan]
Ric Werme says:
July 12, 2010 at 10:05 am
Gail Combs says:
July 12, 2010 at 8:44 am
I don’t know anything about Gail’s chemistry paper, but even if it was good, it wouldn’t surprise me at all that chemists would dismiss it immediately. I work in a graduate chemistry lab and have that happen all the time…people can’t consider anything beyond their own thoughts. As an example, the paper I’m writing now originated from an observation and subsequent idea I had 4 years ago. My advisor (a chemistry professor) said there was no way it would work. So I came in at midnight on a Saturday night/Sunday morning and did the few measurements I needed to confirm that it would at a time that I knew no one would catch me. Guess what?…it worked and turned into one of the foundations of the project I do my graduate work on. Similarly, one of the other pillars of this project was an idea I had on a highly novel and unique instrument modification that had never been considered by anyone in the field. My advisor shot it down immediately. Again, I went behind his back and developed it on my own…it revolutioned this area of measurement and we got a high-impact paper from it immediately.
To summarize, my advisor shot down two ideas of mine immediately that I went on to develop without his permission, and we’ve now published multiple papers because of these ideas and my advisor has (already/to date) secured 7 figures of funding from these ideas. This is pretty standard in most areas of science from what I’ve seen.
-Scott
A few months ago someone suggested a nationwide data-gathering project from golf-course temperature records. These could be used, after a bit of statistical juggling, as a quick double-check for gross official errors. At a minimum.
Speaking of records, this is the most “action” Carefree, Az has ever had on the WEB!!
Thank you Anthony.
When was the place re-paved? Newer asphalt is much blacker than older one… That might increase the apparent temperature at sensor location… The parking markings seem to be in good condition, except of a few lightly worn-out lines…
Airports need good temperature information for safety reasons. I fly a piston powered airplane, which has lower high temperature performance because the engine develops less power, the propeller bites less dense air, and the wings lift less at a given speed. Pilots use the term “density altitude” to correct for the effects of temperature. For example, here in Mojave yesterday, at a field elevation of 2800 ft, the density altitude was 6500 ft. That means you need significantly more runway.
But using airport temperature information for climate measurements is just plain wrong. It’s cheap to piggyback onto airports though……
There is a U.S. Standard Atmosphere lapse rate. The standard atmosphere is supposed to be an average with regard to relative humidity, temperature, and pressure over the U.S. and is neither the dry or wet adiabatic rate but somewhere in between. From 0-11,000 feet it’s given as 3.566 degrees F per 1000 feet.
Useful information for pilots. I’m surprised I couldn’t find much about temperature rises over tarmac except for one guy who embedded a thermocouple in tarmac and compared it with one 4 feet above the tarmac and found a 25 degree C temperature difference in full sun with no wind.
Ground effect is something that pilots need to be aware of and is greatly increased lift at an altitude of one half of your wingspan or lower. It happens due to the air under the wing being compressed between the ground and the wing bottom. I’m not sure how much the air temperature right over the tarmac effects it. Someone with a lot more pilot experience than me might have a feel for it.
I see its effect once in a while with all the great blue herons that fly about where I live. Sometimes they snag a good sized fish, maybe 1-2 pounds, and they’re able to fly with it over the water in ground effect but no higher. They have a wingspan of 6 feet or so and that equates to a ground effect altitude of 3 feet. Pretty low but high enough as it’s just high enough so they can flap without the tips of their wings dipping into the water. Some really great theater is when there’s one fish that’s too big to swallow and more than one bird on the scene. If it’s too big to swallow it’s too big to get out of ground effect with it so one of them will try to make off with it, another will dive bomb him causing him to drop the fish, a third bird might scoop it up and then one of the other actors will repeat the sequence. One morning I watched that go on for a half hour with a total of four different birds. They finally abandoned the fish and out of curiosity I went and looked at it – about a 1.5 pound blue tilapia.