Don Healy sends this photo of Port Angeles, Washington’s USHCN station #456624:
Increasingly, non standard equipment is being observed as substitutes for max/min thermometers and MMTS systems. In this case, vandalism issues with the MMTS forced a change to this station setup in 2002 that was less accessible.
In 2002 a change shows up on the GISS graph for the station. A step of about 2 degrees C seems apparent at that time, but other stations in the area also have a similar event, so it is unclear just how much of a magnitude this equipment change, elevation change, and location change may contribute to the Port Angeles record.
Oddly though, while the change in lat/lon shows up in NCDC’s MMS, not a single mention of the new equipment can be found, nor a mention of the new observing height. MMS still says all the original equipment is in use:
2003-05-17 ] 9999-12-31 PRCP F&P PRIMARY FISCHER/PORTER RRNG PRECIPITATION — 84-880-067 COOP HPD
SRG STANDARD RAIN GAGE — COOP SOD
TEMP MMTS MMTS ELECTRONIC SENSOR TEMPERATURE 4829
According to Don’s survey notes, the old MMTS is still at the old site:
“In 1987 the station was moved to the location on the lawn at the Southeast corner of the Port Angeles City Hall (see photos of Prior Location). It remained there until 2002. The exposed location allowed for repeated acts of vandalism, and while the MMTS still remains on the site, it no longer functions. In 2002, the City of Port Angeles purchased a weather station from the Davis Instrument Company and installed it on the top of the utility pole. NOAA was made aware of the change and accepts the data.”
I wonder if this new equipment gets regular inspections at this height to check for wasp nests in the IR shield or bird excrement in the rain gauge?
UPDATE( Steve Mc):
I’ve done a few figures checking the adjustments at Port Angeles WA. Station moves recorded in 1952, 1985, 1988. TOBS changed from midnight to morning in 1935; to afternoon in 1944, except for a short interval at 10 pm in the last 1940s. MMTS was introduced in 1984. The USHCN stage adjustments are shown here:
Next is a comparison of GISS stage adjustments – Port Angeles has a significant Y2K error. It also has a very large “UHI” adjustment to unlit areas (it has GISS-brightness of 28) that reverses the Y2K and more.
Here is a comparison of the USHCN TOBS version and the GISS adjusted version. Neither shows any particular trend; both show a very warm 1998 with something of a mean-reversion since then.