[CF-metadata] date and time

From: John Graybeal <graybeal>
Date: Fri, 24 Oct 2008 09:58:45 -0700

On Oct 24, 2008, at 12:37 AM, Jonathan Gregory wrote:

> I think we could define other standard_names for such time-like
> quantities of the form time_since_EVENT if they are needed.

ooh, it would be very useful to have time_since_start_of_year,
time_since_start_of_day, and time_since_start_of_mission. I could
label a lot of values using those.

They assume the existence of another variable that reflects the start
of the year, day, or mission; I am not sure whether that has to be
explicitly detailed within this variable, explicitly pointed to
another variable, or whether it can be inferred. (I prefer the middle,
and propose that below.)

So I now suggest the following for consideration:

time_from_device: time reported by some device (data source)
    (I just changed the form of this name so that it is collocated
with the other time variables)

The following three can each have an attribute pointing to the
variable that determines the time sequence; for example, the attribute
could name another source of time values, and the current year is
established by those values. The units in all 3 are the same as the
units for time.

time_since_start_of_year: amount of time elapsed since the current
year began
time_since_start_of_day: amount of time elapsed since the current year
began
time_since_start_of_mission: amount of time elapsed since the current
mission began

For completeness, a more general-purpose variable is as follows. I
don't have a need for this yet, so it can be deferred until such time:

time_since_event: amount of time elapsed since the referenced event

I appreciate continued feedback on these requests.

John
Received on Fri Oct 24 2008 - 10:58:45 BST