Recommendation:

We recommend that date-time information in granule file names adheres to the following guidelines:

  • Adopt the ISO 8601 [11] standard for date-time information representation.
  • If describing a date-time interval, the start date-time should appear before the end
    date-time.
  • Date-time fields representing the temporal extent of a granule's data should appear before any other date-time field in the file name.
  • All date-time fields should have the same format.

The recommended date-time formats are:

  • Full resolution

YYYYMMDDThhmmss[,.]f+Z
YYYYMMDDThhmmssZ

  • Reduced resolution

YYYYMMDDThhmmZ
YYYYMMDDThhZ
YYYYMMDD
YYYY-MM
YYYY

Where:

  • Y is a digit used in the time element “year”
  • M is a digit used in the time element “month”
  • D is a digit used in the time element “day”
  • T is the separator between the date and time parts
  • h is a digit used in the time element “hour”
  • m is a digit used in the time element “minute”
  • s is a digit used in the time element “second”
  • [,.] the decimal mark – either the comma or the full stop.
  • f is a digit used in the decimal fraction of a second
  • + means "one or more digits"
  • Z is UTC time zone designator

Recommendation Details: It is commonplace to find date-time information in Earth Science granule file names; however, its formatting varies. ISO 8601 is an international standard for representing dates and times of the Gregorian calendar in many interoperable formats and with differing level of detail. The recommended formats imply:

  1. Date-time information should always be in the UTC time zone.
  2. There are no limits on the highest date-time resolution.
  3. The delimiter between the seconds and the fraction of a second can only be the comma or the full stop. The choice should take into account which of these two characters is considered safe for the adopted granule file naming scheme.