[MITgcm-support] KPP & OB file

[Martin Losch]

Forgot to say: the model does the interpolation in time to each  
timestep, but that's "only" a linear interpolation.
M.
On 2 Mar 2007, at 10:02, Martin Losch wrote:

> Hi Riema,
>
> In order to use KPP you have to put "kpp" into your local  
> packages.conf and you have to set #define SHORTWAVE_HEATING in your  
> local CPP_OPTIONS.h because kpp requires a two band incoming  
> radiation (short wave= visible light and long wave = the remaining  
> part). The model will stop if you don't have short wave heating  
> defined.
> You don't need to set any other parameters, unless you are unhappy  
> with the choice of default values for, say, Ricr, etc. (see  
> kpp_readparms.F). I have never changed them so far, but it's  
> possible. KPP then compute vertical mixing coefficients etc based  
> on your present vertical stratification, vertical shear, surface  
> fluxes, etc. (see, eg., Large et al 1994 for details)
>
> OBCS:
> exp4 gives an example of how to specify CONSTANT (in time) open  
> boundary values from files:
>  useOBCSprescribe = .TRUE., (enables reading from files in general)
>  OBNuFile = 'OBmeridU.bin', (example of a file)
> [...]
> these files were generated with exp4/input/gendata.m. The script  
> tell you that a filed for the northern (southern) boundary should  
> have the dimension (nx,nr) and for eastern (western), (ny,nr).
>
> If you want to specify time dependent boundary values you can do  
> that too. For example, you have hourly data you have create a field  
> (nx,nr,nt), where nt is the number of "hours" you have. and then  
> you use the parameters
>   periodicExternalForcing=.TRUE.,
>   externForcingPeriod=3600.,
> in the file "data", in namelist PARM03. If your data is the same  
> after say 12 hour (ie., that you want to use the fields repeatedly)  
> then add this parameter in data
>  externForcingCycle=43200.,
> These parameters that control reading external forcing data (also  
> surface forcing if you use any) in general. the drawback is that  
> all forcing data have to be at the exact same time levels. The  
> advantage is , that it's simple.
> The alternative is to use the exf-package, where you can use  
> different frequencies etc for different input fields, but it's also  
> far more complicated.
>
> Does that help?
>
> M
>
> On 2 Mar 2007, at 02:45, Riema Rachmayani wrote:
>
>> thanks martin for KPP...KPP is  special in that you have to set  
>> #define SHORTWAVE_HEATING in  CPP_OPTIONS.h in addtion...so you  
>> mean that KPP is used ONLY when we define shortwave_heating??so i  
>> dont need to change Ricr  for my internal wave case...because i  
>> thought it influence of dynamic stability...
>>
>> one more question :
>>
>> now i'd like to ask about open boundaries file, as in \verification 
>> \exp4\input\data.obcs :
>>
>> # Open-boundaries
>>  &OBCS_PARM01
>>  OB_Jnorth=80*-1,
>>  OB_Jsouth=80*1,
>>  OB_Ieast=42*-1,
>>  OB_Iwest=42*1,
>> #useOrlanskiNorth=.TRUE.,
>> #useOrlanskiSouth=.TRUE.,
>> #useOrlanskiEast=.TRUE.,
>> #useOrlanskiWest=.FALSE.,
>>  useOBCSprescribe = .TRUE.,
>>  OBNuFile = 'OBmeridU.bin',
>>  OBSuFile = 'OBmeridU.bin',
>>  OBWuFile = 'OBzonalU.bin',
>>  OBEuFile = 'OBzonalU.bin',
>>  OBWsFile = 'OBzonalS.bin',
>>  OBWptrFile(1) = 'OBzonalS.bin',
>>  &
>> # Orlanski parameters
>>  &OBCS_PARM02
>> #Cmax=0.45,
>> #cVelTimeScale=1000.,
>>  &
>>
>> in the blue line means that data  open boundaries is given from  
>> data observation/prediction?? may i know how to read and to write  
>> (format) for that open bondaries file?? is the data read every  
>> time step or every one hour??how to interpolate them?? in what  
>> routines that files read??
>>
>> in my case, i'm gonna use tidal prediction data of eta (elevation)  
>> from ORITIDE from Ocean Research Instute, University of Tokyo, the  
>> data is in every one hour, and usually we use spline cubic  
>> subroutine to interpolated one hour data become every time step  
>> data, so that every time step data/value used for open boundaries  
>> input/value...how to modify my case in MITgcm?? because as far i  
>> can see there is no open boundaries file for eta...
>>
>> thank you,
>> regards
>> rima
>>
>>
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