How not to measure temperature, part 47

/ January 20, 2008

ajo_part47.jpg

Ajo, AZ USHCN Station photographed by Bob Thompson

But wait, theres more:

Ajo_General_Area

I’ve posted about stations that had proximity to a/c units before, but this one is of particular interest since it has dual a/c units to its west and east. Given that wind tends to hug the side of a building (laminar flow) this provides potential for transferring waste heat from the a/c units to the MMTS sensor. Of course there is the bias based on the MMTS sensor proximity to the building, and the wall corner that it is built into will like provide a night time IR radiative bias near the sensor also. Combined, this station warrants a CRN 5 rating.

Honestly, I don’t know how the COOP manager for the NWS would allow such a poor placement.

This station has an incomplete temperature record, since it apparently has gone through some moves, but the latter part of its graph at the current location seems to confirm a step bias due to the placement.

Ajo_Temperature_Record

Bob indicates from the curator that teh station used to be on a nearby hilltop, but was moved, but according to NCDC’s MMS records for COOP station # 020080 it remains on the hilltop today:

LOCATED ON KNOLL SURROUND BY FLAT TERRAIN. KNOLL & SURROUND AREA PARTIALLY COVERED DESERT SCRUB. SITE OVERLOOKS THE MINE PIT APPROX 5 MI TO THE SW-W. LITTLE AJO MTNS 1.0 MI SSE-SW

The NCDC MMS database system is fraught with such discrepancies. I would suspect that researchers that use a lat/lon change to trigger examinations for a step function in the temperature record could miss this station. The lat/lon record for this station is changed in 1998 but the description remains unchanged.

Even using the old lat/lon in the MMS database puts this station not on a hill, but in a scrub field.

See Google Earth The mine pit referenced does have a hill to the east, which may be the location that was originally referenced. There does appear to be places where a Stevenson Screen may have been placed.

Alas, we may never know.

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15 thoughts on “How not to measure temperature, part 47”

  2. Jeff,
    You do realize, don’t you, that NASA GISS uses complex algorithms to adjust for this sort of “garbage”?
    //sarcasm off

  6. Knowing that national policy and international policy is going to be based on this very sophisticated technology (dang I wish I could spell).
    It upsets me to see thousands of dollars of our tax dollars spent to develope advanced measurement devices and the to waste it all with poor location.
    OH I know, the operator didn’t want to get his feet wet when it rained.
    Bill

  7. From what I’ve seen, every station has its (complex) story.
    Just looking at the current site to bin the data quality is very superficial. As an example, though rated poorly, I’d suggest that Norris, MT has had quite consistent data over its life (lives really) due to large medium distance local climate effect even though the sensor immediate micro-climate(s) may not meet the siteing guidelines (or have met it in the past at its (nearby) previous locations.
    I’m still looking for a detailed description of the “system” the network is attempting to measure (all those soil temp data at the ag stations may be a better measure).

  8. Bill, Firefox has built in spell check, if I might recommend another browser. 😉
    Actually, Evan, I think I see a street light waaaaaaaaaaaaaaaaayyyyyyyyy over to the right in the back.
    Perhaps we should make it a rule: no moving stations. If we catch you, you’ll get a big fine for wasting tax payer money by creating an imaginary trend. Just a thought.

  10. A/C units would impose a warming bias in summer,but wouldn’t they also impose a cooling bias in winter? If the A/C was used more in winter than summer, the averall bias would be cooler.
    The point being, we can’t be sure even of the direction of the bias, let alone the magnitude. How can a NASA algorithym possibly correct for this bias.

  11. Actually, it’s still a warming bias in the winter, even without the waste heat. The dang things are dandy heat sinks. Of course the house itself is a killer in that regard. One wouldn’t be a bit

  13. Certainly the GISS prcedures and results continue to raise questions. Also, when one calculates his own data to verify whether his model forecasts matches observed — or calculated — data, then red flags should be raised in the media, in Congress which funds the efforts, and even the head boss at NASA. My question: what auditing has been done or could be done of GISS methods to convert observed data to a single number? I have read Hansen’s documentation offered at RealClimate, and that is far from satisfactory. Has somebody gotten a hold of the algorithm used in the conversion process? Is this algorithm stable from year to year? Could the algorithm be consistent year-after-year and be flexible enough to handle variable number of reporting stations and other parameters that change year by year? Are the results reproducible?

  14. “My question: what auditing has been done or could be done of GISS methods to convert observed data to a single number?” (etc.)
    Holy canole!
    Tell him the story of “Free the Code”, Rev!
    (Pull up a chair, An, baby, you’re gonna enjoy this . . .)
    REPLY: see part 48, just posted, first.

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