How not to measure temperature, part 62

One of the key criteria for placement of weather stations in the COOP, and by extension, the subset USHCN network is the requirement for a “warm body” (an observer) to read the thermometer daily, and write down the max and min (plus rainfall) in the B-91 observers log for monthly submission to the National Climatic Data Center.

By that criteria for a live observer then, manned facilities such as fire stations are often prime locations for NOAA climate monitoring stations.

Monroe, NC Fire Department, a USHCN station – Click for larger image

The problem with many fire stations is that they are placed right in the middle of the things they are designed to protect – towns and cities. That’s the case with Monroe, North Carolina’s USHCN Climate station of record. I visited this station shortly before my visit to NCDC as part of the road trip you all were kind enough to send me on with funding help (again my thanks).

One of the most interesting things is the view the MMTS temperature sensor has at the major highway intersection that the fire station resides on. In addition to the brick wall about 28 feet away acting as a nighttime heatsink, possibly biasing Tmin readings, and the a/c units, the MMTS has a clear view of traffic and the new local Rite Aid Store:

Monroe, NC USHCN Station looking west

 The aerial view gives a better idea of the environment that the MMTS temperature sensor sees:

Click for a larger image

A complete set of station pictures are available here at this link.

The question then becomes: what is being measured? Temperature and along with it climate trends or that plus increasing traffic and city growth? The plot from GISTEMP shows an abrupt increase in temperature starting around 1970, after a period of cooling:

Click for original graph from GISTEMP

The MMTS has been at this location since June 9th of 2003. Prior to that it was located further south of the city. As the Google map from NCDC’s MMS interactive database shows, the location of the station has been getting steadily closer to the center of the town center:

The blue marker is the current location at the fire station, the southernmost marker is the oldest, dating from 1948-08-01 to 1954-02-01, while the  middle marker dates from 1954-02-01 to 2003-06-09. Unfortunately while temperature data for this location extends back to 1888, location data in NCDC’s database only goes back to 1948.

These moves don’t explain the abrupt jump around 1970, which appears to be a discontinuity. However a check of adjacent stations in the are also show a similar jump at the time. So it appears to be natural. The station at Charlotte, NC which you can see here, has a similar jump around 1970. It is 48 kilometers (29.8 miles) away.

Click for original graph from GISTEMP

So the jump appears to be natural. But notice that Charlotte’s Douglas Airport  record shows a cooling trend post 1990 while Monroe, just 30 miles away shows a warming trend. Which one represents the true temperature trend?

The difficulty in figuring this out is part of the problem with the USHCN and COOP network, because sorting out stations moves, population growth, and changes around the sensor all figure into the record. In my opinion, disentangling these elements to get the true climate change signal requires more than just a blanket application of an algorithm and adjustments, it requires a detailed examination of the station history and measurement environment as well.

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Jeff Alberts
May 19, 2008 11:09 pm

It also looks like the firestation lawn is well watered, very different from the other grassy areas in the aerial photo. More humidity for the sensor.

Pierre Gosselin
May 20, 2008 2:55 am

Sure is a lot of pavement and brick around it. What correction factor does this sensor get?
REPLY: I don’t know, there is not a table of correction factors on a station by station basis that I can refer to.

May 20, 2008 4:45 am

That berm between the road and the sensor is as tall as the sensor. That’s going to affect both affect night time cooling and wind patterns all the time.

May 20, 2008 5:04 am

That’s an interesting point about how good the fire department’s lawn looks. Since North Carolina is in a drought similar to myself in Georgia, watering lawns is all but prohibited. They wouldn’t be cheating would they?

David Smith
May 20, 2008 5:27 am

Anthony, what is the sensor’s height above grade?
Photo angles can be deceiving but they seem to indicate this sensor is 5 feet or less above the ground. That can make a difference, of course.
REPLY: If you look at all the photos here
You will see that it is actually in a depression, and that the main highway surface is about even with the MMTS head.

Bill in Vigo
May 20, 2008 5:46 am

And the saga continues. I would wonder if the regular application of RoundUp around the base of the sensor allowing the nice dry soil to show might also be a bias. I guess it is easier than the weed eater. The condition of the USHCN makes one wonder why not use sensors that report via satellite data link like the ocean sensors. Then the man made bias might be greatly eliminated.
Just wondering
Bill Derryberry

Scott Finegan
May 20, 2008 5:52 am

The annual mean temperature charts are from GISTEMP, can we trust the step about 1970 is not an across the board adjustment?
That over 50 percent of the USHCN appears to have unknown accuracy problems, missing or poor quality documentation on station moves, and gaps in the temperature data.
Some questions that need to be asked of the managing agency, and answered are:
What triggers a need for a station move?
Could the potential move be anticipated? (age and health of observer)
How are the new station sites selected?
Is there a process, designed to maintain quality (pre selection), or a mad rush to minimize gaps in the data, regardless of quality?

May 20, 2008 6:10 am

Reminds me of the Lenoir, NC USHCN station. Just a few feet from the fire station and across the street from a shopping center.

May 20, 2008 6:21 am

Might be the difference between a fescue lawn and a bermuda lawn. The bermuda is just greening up now.
North Carolina has had some drought problems and I would be surprised if the FD watered.

May 20, 2008 6:44 am

Dang Anthony, I tried to find a station near me to survey, but I thought all the ones in my area were already done. Marion is about an hour away.
Where can I find which stations in my area (just west of Charlotte, NC) have not been done?
REPLY: Just look at and see if a station has been posted.
I have most of NC done but a one remains that you could get. Reidville, NC at the experiment farm there.

May 20, 2008 7:01 am

… And just look at the color of the roof. I see they are taking the “Green Movement” seriously.

Evan Jones
May 20, 2008 12:55 pm

That’s funny. The ground shot makes it seem like a sea of green, and the aerial shot is a teeny green triangle.

Jim Arndt
May 20, 2008 3:28 pm

Hi Anthony,
A few questions. First what it the population of Monroe? When did the highway get built? When did the Riteaid get built? The fire station itself looks fairly modern and looks to have a steel roof.These may answer some of the anomalies in the record.
REPLY: Jim the MMTS has only been there at the fire station since June 2003, and most of the issues are further back than that. I have no info on the prior location.

May 20, 2008 4:59 pm

[…] How not to measure temperature, part 62 One of the key criteria for placement of weather stations in the COOP, and by extension, the subset USHCN network is […] […]

Evan Jones
May 20, 2008 8:30 pm

Wow! Number 6!
I think we need to start pounding on the table and asking NOAA what corrections they are making for these violations.

May 21, 2008 5:01 am

[…]… Share and Enjoy: These icons link to social bookmarking sites where readers can share and discover new web pages. […]

Evan Jones
May 21, 2008 9:37 am

Asheville, NC
To whom it may concern:
Attached is a link to photographs of the surface tempe5rture station at [fill in the blank].
Known CRN violations (according to the CRN handbook) are as follows:
[fill in the blank(s)]
Please inform me of the USHCN siting adjustments that are applied to this station to offset the above violation(s). (Siting adjustments only, please. If TOBS or homogenization, etc., is to be included, please list separately.)
Stamped, self-addressed envelope enclosed.
Thank you for your kind cooperation,
[Return Address]

May 28, 2008 1:57 pm

[…] reason why temperatures are rated as high as they are is also highlighted in this blog.  Putting a weather station in a Fire Station car park in the middle of a city is not […]

June 11, 2008 3:17 pm

Its my opinion that all city monitors should be removed from the data because they are being warmed by the cities and do not reflect true temps.
Only rual stations should be used to monitor the earths temp.

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