time ref

time_ref

time_ref

Reference time (yyyymmdd.f) used to compute relative time: elapsed time interval since reference-time.

option =

routine = mod_scalars.F

keyword = TIME_REF

input = roms.in

---

Reference time used to define the "units" attribute written to the output netcdf files.

For so-called realistic applications where the model time corresponds to a certain calendar date, time_ref will be a floating point number > 0 in the format (yyyymmdd.f)

For example, setting TIME_REF=20020115.5 in your roms.in will yield the following CF-Comliant time units attribute:

   units = "seconds since 2002-01-15 12:00:00" 

There are some default special values for TIME_REF:

If TIME_REF = -2, model time and DSTART are in modified Julian days units. The "units" attribute becomes:

   units = "since 1968-05-23 00:00:00 GMT:

If TIME_REF = -1, model time and DSTART are in a calendar with 360 days in every year (30 days each month). The "units" attribute is:

  units = "seconds since 0000-01-01 00:00:00"

If TIME_REF = 0, model time and DSTART are in a common year calendar with 365.25 days. The "units" attribute is:

  units = "seconds since 0000-01-01 00:00:00"

There are several user postings about time keeping in ROMS on the User Forum