[MITgcm-support] time-dep-wind-file

[Matthew Mazloff]

Hi Ming,

1)  I think the best way to do it (though I may be wrong) is to use the 
external forcing (exf) package.  There is a short description in section 
8.2 of the manual.  You should check out the verification experiments 
too.  I know lab_sea and many of the global experiments use the exf package.

disclaimer: I am not an expert on the MITgcm and so do not take my words 
as the only or best way to do things. 

That said, to enable the EXF package, all I do is add
exf
in  packages.conf which is found in my code folder. (this makes sure the 
package is compiled)
(PACKAGES_CONFIG.h is automatically generated and sets  #define ALLOW_EXF)

I don't think you need to add anything in ECCO_CPPOPTIONS to use wind 
stress but here I may be wrong.

Then in my input folder I add a data.exf file with instructions on how 
to treat the files.  see for example the very complete data.exf:
http://mitgcm.org/cgi-bin/viewcvs.cgi/packages/realtime_forcing/data.exf?rev=HEAD&content-type=text/vnd.viewcvs-markup
or go to cvs repository online at
http://mitgcm.org/cgi-bin/viewcvs.cgi/
click on
MITgcm / packages / realtime_forcing / data.exf

2) You should use a separate file for X and Ycomponent of the wind 
stress and no need to include the time in the file so its like
file ustress:  talx(t1), talx(t2), talx(t3) ....
file vstress:  taly(t1) taly(t2) taly(t3) ....

3) There might be but I don't know.  If you can't find it in the manual 
I am doubtful it exists.  I hope if I'm wrong someone will correct me.

Good luck!
-Matt

Ming Guo wrote:

> Hi, Matt,
> thanks for your help, but I am still a little confused,
>
> 1. you mean I should generate a file, "data.exf", to specify the 
> forcing interval and period? no need using command in "data", like
> "externalForcingPeriod"...
>
> 2. what is the format of time-dep-wind-forcing file? Is it like
> talx1 taly1 time1
> talx2 taly2 time2
> talx3 taly3 time3
> ...
>
> 3. is there some commands to be added in file "data" to read the 
> time-dep-wind file? I can't find it in the manual.
>
> Thanks,
> Ming
>
>
> On Fri, 5 Aug 2005, Matthew Mazloff wrote:
>
>> Hi Ming,
>>
>> You now write your file with several time records.  So the record for 
>> t = 0 goes first, then the next time record is written into the file 
>> following that record, and so on.  In data.exf you then specify the 
>> period so the model knows how over what interval each record is 
>> valid.  I believe with the wind stress the model linearly 
>> interpolates between the two time records so the transitions are smooth.
>>
>> data.exf will have something like:
>> ustressstartdate1=19920601,
>> ustressstartdate2=30000,
>> ustressperiod=43200.0,
>>
>> so that t = 0 is at June 1, 1992 at 3am and a new record is valid 
>> every 43200.0 seconds.
>>
>> To actually generate the file just add the next record on after the 
>> first.
>> so that the record is valid for
>> from t = 0:nts
>> NX*NY*(t)+1 : NX*NY*(t)
>>
>> Hope I helped,
>> -Matt
>>
>> Ming Guo wrote:
>>
>>> Hi,
>>> anyone can tell me how to creat the time dependent wind stress file?
>>>
>>> Thanks,
>>>
>>> Ming
>>>
>>>
>>> _______________________________________________
>>> MITgcm-support mailing list
>>> MITgcm-support at mitgcm.org
>>> http://mitgcm.org/mailman/listinfo/mitgcm-support
>>>
>>
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