[MITgcm-support] how long is a year? & monthly mean forcing

[Martin Losch]

Hi Jonny,

I think, it should work. I would change the start date to something like 197901015 (the year doesn’t matter, but that way the model interprets the records as a monthly mean centered at mid-month).

Martin

On Apr 11, 2014, at 5:23 PM, Jonny Williams <Jonny.Williams at bristol.ac.uk> wrote:

> Thanks a lot for that Martin! Does my implementation of the monthly mean forcing look correct to you?
> 
> Thanks again
> 
> Jonny
> 
> 
> On 11 April 2014 15:11, Martin Losch <Martin.Losch at awi.de> wrote:
> Hi Jonny,
> 
> if your calendar (see data.cal) is “gregorian”, then it is 365 and 366 in leap years. So the average year is 365.25, but you’ll get into trouble with these assumptions at the turn of a century, when leap years are skipped (except for millenia …)
> 
> Your parameters make the model believe that there are twelve records that repeat each year (climatological seasons).
> 
> Martin
> 
> 
> On Apr 11, 2014, at 3:57 PM, Jonny Williams <Jonny.Williams at bristol.ac.uk> wrote:
> 
> > Hi everyone
> >
> > I've got a couple of (hopefully) quick questions.
> >       • In the MITgcm, how long is a year? Is it 365 or 365.25 days?
> >       • I want to use monthly mean forcing for the EXF and OBCS packages. As far as I can tell, I need to use the format in my data.exf file which I have copied and pasted below. Is this correct?
> >  &EXF_NML_01
> >  ...
> >  precipstartdate1  = 19790101,
> >  precipstartdate2  = 000000,
> >  precipperiod      = -12.,
> >  atempstartdate1   = 19790101,
> >  atempstartdate2   = 000000,
> >  atempperiod       = -12.,
> >  aqhstartdate1     = 19790101,
> >  aqhstartdate2     = 000000,
> >  aqhperiod         = -12.,
> >  swdownstartdate1  = 19790101,
> >  swdownstartdate2  = 000000,
> >  swdownperiod      = -12.,
> >  lwdownstartdate1  = 19790101,
> >  lwdownstartdate2  = 000000,
> >  lwdownperiod      = -12.,
> >  uwindstartdate1   = 19790101,
> >  uwindstartdate2   = 000000,
> >  uwindperiod       = -12.,
> >  vwindstartdate1   = 19790101,
> >  vwindstartdate2   = 000000,
> >  vwindperiod       = -12.,
> >
> > and
> >
> > &EXF_NML_OBCS
> >   obcsNstartdate1   = 19790101,
> >   obcsNstartdate2   = 00000,
> >   obcsNperiod       = -12.,
> > #
> >   obcsSstartdate1   = 19790101,
> >   obcsSstartdate2   = 00000,
> >   obcsSperiod       = -12.,
> > #
> >   obcsWstartdate1   = 19790101,
> >   obcsWstartdate2   = 00000,
> >   obcsWperiod       = -12.,
> > #
> >   obcsEstartdate1   = 19790101,
> >   obcsEstartdate2   = 00000,
> >   obcsEperiod       = -12.,
> >
> >  &
> >
> > Many thanks!
> >
> > Jonny
> >
> > --
> > Dr Jonny Williams
> > School of Geographical Sciences
> > University of Bristol
> > University Road
> > BS8 1SS
> >
> > +44 (0)117 3318352
> > jonny.williams at bristol.ac.uk
> > bit.ly/jonnywilliams
> > _______________________________________________
> > MITgcm-support mailing list
> > MITgcm-support at mitgcm.org
> > http://mitgcm.org/mailman/listinfo/mitgcm-support
> 
> 
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> 
> 
> -- 
> Dr Jonny Williams
> School of Geographical Sciences
> University of Bristol
> University Road
> BS8 1SS
> 
> +44 (0)117 3318352
> jonny.williams at bristol.ac.uk
> bit.ly/jonnywilliams
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