Satellite microwave radiometers, however, are equipped with laboratory -
calibrated platinum resistance thermometers, which have demonstrated stability to thousandths of a degree over many years, and which are used to continuously calibrate the satellite instruments once every 8 seconds.
The device they use is not a thermistor it works sort of similar to that by variation of resistance with temperature but is called
a platinum resistance thermometer.
The average temperature at a site would be determined as the arithmetic average of hourly, automated data recording using
a platinum resistance thermometer or similar.