...
As expected, the frequency offset shows a temperature dependence in the system clock oscillator. We do not have a measurement of the temperature inside the data system. The top panel in the plot below shows a time series of the 2 meter ambient air temperature on the tower, with the NTPFreqOffset, for a cool 3 day period in April. When the ambient air temperatures is below 5 deg C, the system clock oscillator does not show a pronounced temperature drift. The bottom panel shows a close relationship between the NTPClockOffset and the derivative of NTPFreqOffset, indicating how NTP adjusts the clock.
On a warmer 3 day period in July, where the temperatures were all above 5 degC, the temperature effect on the system clock oscillator is very evident.
