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

[Martin Losch]

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
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