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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 at 2 meters on the tower, along 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 an obvious temperature effectrelation.
The bottom panel shows a close relationship between the NTPClockOffset and the time derivative of NTPFreqOffset, indicating how NTP adjusts the clock.
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