Page History

...

Recommendation Details: Earth Science data products must preserve time-related information with sufficient precision to resolve all timescales relevant to the data itself, to other data with which it may be intercompared, and to conventions for the numeric representation of time, such as Coordinated Universal Time (UTC).  Geoscientific datasets commonly report time in intervals (such as seconds) measured from a particular epoch.  Resolving one second on the 50+-year timescale from the UNIX/POSIX epoch (00:00:00 UTC on 1 January 1970) to the present day can require up to ten significant digits of temporal resolution, whereas the IEEE-754 single-precision (32 bit) floating point representations preserves at most seven significant digits.  Resolving time to the nearest microsecond can require up to six more digits, for a total of sixteen digits, approximately the maximum precision of an IEEE-754 double-precision (64-bit) floating point number.  Therefore, preserving sufficient temporal precision to label, store, and intercompare geoscientific data requires double-precision storage.

...