[time-nuts] IEEE Spectrum - Dec 2017 - article on chip-scale atomic frequency reference

[Mark Sims]

In the standards definitions that include "at sea level", the question these days is "which sea level?".  As ocean temperature changes sea level will change (except maybe in Washington DC).  Will the standards be amended to include something like "at sea level in 1990" or will the value being defined drift around with the changing sea level?