Ajo, AZ USHCN Station photographed by Bob Thompson
But wait, theres more:
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.
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.