from The American Heritage® Dictionary of the English Language, 5th Edition.
- noun A resistor made of semiconductors having resistance that varies rapidly and predictably with temperature.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun a
resistorwhose resistancevaries rapidlyand predictablywith temperatureand as a result can be used to measure temperature.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- noun a semiconductor device made of materials whose resistance varies as a function of temperature; can be used to compensate for temperature variation in other components of a circuit
from The American Heritage® Dictionary of the English Language, 4th Edition
from Wiktionary, Creative Commons Attribution/Share-Alike License
Maybe what you have is a thermistor, which is not linear.
That could be either good or bad depending upon the kind of thermistor and the mass that it is attached to.
The probable reason for this: "poorly-situated" stations are predominantly MMTS (aspirated thermistor) sites which have a known cool bias compared to the Liquid in Glass stations (which tend to make up the "well-sited" sites.)
I was looking for something subtle like thermistor drift but what you describe is classic FUBAR.
A hybrid should be developed that uses a mechanical thermometer that is read electronically rather than a thermistor element that is subject to drift and noise.
The new system is thermistor-based with a “beehive like” instrument shelter, whereas the older systems consisted of liquid-in-glass thermometers, mounted inside a Cotton Region Shelter Stevenson Screen.
The NWS has replaced a majority of the liquid-in-glass thermometers in wooden Cotton-Region shelters with thermistor based maximum-minimum temperature systems MMTS housed in smaller plastic shelters.
In other words every thermistor needs its own calibration if it is to be accurate .02 C is possible over wide ranges.
These are thermistor sensors, so in practice the error would be a constant offset from reading to reading, closing that 3 degree window down to +/- 1 degree.
Is the temp sensor a glass thermometer or a thermistor?