REFERENCE: MITgcm Documentation
In input file data.cal, the following settings are commonly used:
$CAL_NML
TheCalendar='gregorian',
startDate_1=YYYMMDD,
startDate_2=HHMMSS,
&
Here, TheCalendar sets usingGregorianCalendar=.TRUE. (see cal_set.F).
The cal package will track weekdays and leap years based on a reference date. A Gregorian year is 365 days with a day added on for leap years. The maximum number of days in a month is 31 days.
We're interested in outputting the model state and diagnostics monthly or yearly intervals (among others). Here is how to treat intervals in data
| interval | days | seconds |
|---|---|---|
| 1 year | 365.25 | 31 557 600 |
| 1 month | 30.5 | 2 635 200 |
| 30 days | 30 | 2 592 000 |
| 1 week | 7 | 604 800 |
| 1 day | 1 | 86 400 |
| 1 hour | ~0.04 | 3600 |
In data, parameters like pChkptFreq, chkptFreq, dumpFreq, and monitorFreq use intervals defined in seconds. The timestep, often defined in data by deltaT, determines the number of time steps wanted in the simulation nTimeSteps based on the interval the model needs to run.
If using the DIAGNOSTICS package, you define intervals of model output by seconds in namelist data.diagnostics's frequency(n) parameter.
Remember to turn on the Calendar package at runtime. In data.pkg add the following line:
useCal=.true.,
Otherwise, you will likely see an error like:
CAL_GETDATE: called too early (cal_setStatus=-1 )
ABNORMAL END: S/R CAL_GETDATE