[MITgcm-support] RBCS relax u velocities problem

[Dustin Carroll]

Hi Jean-Michel,

Thank you for your suggestions. The Um_Ext and Vm_Ext diagnostics are very helpful.

Looking at my Um_Ext data, the relaxUFile='rbcsU.bin', is being loaded. The initial Um_Ext velocity profile at the plume looks like the relaxUFile profile * ~10^-5.

However, it does not relax to the prescribed value over time. It doesn't stay constant, but varies almost unnoticeably (by ~10^-8)

For this model, I want to relax the u velocity in a grid cell from 0 to ~0.5 m/s over 86400s. Is setting rbcsIniter=0 and tauRelaxU=86400 the correct way to do this? 

Thanks,
Dustin


On Jan 15, 2014, at 11:39 AM, Jean-Michel Campin <jmc at ocean.mit.edu> wrote:

> Hi Dustin,
> 
> Recently (Dec 31, 2013), pkg/rbcs can output to binary files 
> the various relaxation masks that are used. This is activated
> for debugLevel greater or equal to 3.
> 
> And if your set-up does not have complex momentum forcing
> (e.g., only surface wind stress and RBCS) you can diagnose the horizontal 
> momentum external forcing contribution (3-D field) which includes 
> the RBCS part: 
> diagnostics 'Um_Ext  ' & 'Vm_Ext  '
> This will also contain the surface wind stress, but for any k > 1,
> you should only find the forcing comming from RBCS.
> 
> Cheers,
> Jean-Michel
> 
> On Wed, Jan 15, 2014 at 09:49:25AM -0800, Dustin Carroll wrote:
>> Hi Martin,
>> 
>> Thanks for the reply. Good question, I am relaxing the plume sufficiently far away from the boundaries or a land mask. 
>> 
>> Are there any diagnostics for the rbcs pkg so I can see if the mask are being loaded properly, etc?
>> 
>> Cheers,
>> Dustin
>> 
>> On Jan 15, 2014, at 9:40 AM, Martin Losch <Martin.Losch at awi.de> wrote:
>> 
>>> Hi Dustin,
>>> 
>>> does it make sense to use the same mask for U as for T/S ? The U points are staggered by half a grid cell on a C-grid and if you are only restoring near the boundaries this might lead to unexpected results (i.e. relaxing the velocites on the boundaries, that are always masked to zero)?
>>> 
>>> Martin
>>> 
>>> On Jan 15, 2014, at 11:50 AM, Dustin Carroll <dcarroll at uoregon.edu> wrote:
>>> 
>>>> Hi All,
>>>> 
>>>> I am trying to use the RBCS package to create a plume in a 3-D model domain. The T,S, and tracer fields are relaxing properly, but the velocities are not relaxing. 
>>>> 
>>>> I looked through the RBCS pkg code and it looks this functionality is supported, are there any special flags / settings I need to get this work?
>>>> 
>>>> I am setting:
>>>> 
>>>> #undef DISABLE_RBCS_MOM
>>>> #define ALLOW_RBCS
>>>> 
>>>> in my CPP_OPTIONS.h file.
>>>> 
>>>> 
>>>> In my STDOUT.0000 file I see that the rbcsU.bin files are loading. It only shows the loading of two masks though.
>>>> 
>>>> (PID.TID 0000.0001) // =======================================================
>>>> (PID.TID 0000.0001) // End MONITOR EXF statistics
>>>> (PID.TID 0000.0001) // =======================================================
>>>> RBCS_FIELDS_LOAD, it=         0 : Reading new data, i0,i1=    1    1 (prev=    1    0 )
>>>> (PID.TID 0000.0001)  MDS_READ_FIELD: opening global file: rbcsT.bin
>>>> (PID.TID 0000.0001)  MDS_READ_FIELD: opening global file: rbcsT.bin
>>>> (PID.TID 0000.0001)  MDS_READ_FIELD: opening global file: rbcsS.bin
>>>> (PID.TID 0000.0001)  MDS_READ_FIELD: opening global file: rbcsS.bin
>>>> (PID.TID 0000.0001)  MDS_READ_FIELD: opening global file: rbcsMask.bin
>>>> (PID.TID 0000.0001)  MDS_READ_FIELD: opening global file: rbcsMask.bin
>>>> RBCS_FIELDS_LOAD, it=         0 : Reading new data, i0,i1=    1    1 (prev=    1    0 )
>>>> (PID.TID 0000.0001)  MDS_READ_FIELD: opening global file: rbcsU.bin
>>>> (PID.TID 0000.0001)  MDS_READ_FIELD: opening global file: rbcsU.bin
>>>> RBCS_FIELDS_LOAD, it=         0 : Reading new data, i0,i1=    1    1 (prev=    1    0 )
>>>> (PID.TID 0000.0001)  MDS_READ_FIELD: opening global file: rbcsU.bin
>>>> (PID.TID 0000.0001)  MDS_READ_FIELD: opening global file: rbcsU.bin
>>>> RBCS_FIELDS_LOAD, it=         0 : Reading new data, i0,i1=    1    1 (prev=    1    0 )
>>>> RBCS_FIELDS_LOAD, it=         0 : Reading new data, i0,i1=    1    1 (prev=    1    0 )
>>>> 
>>>> Here is my data.rbcs file, I am using the same mask for T,S, ptracer and u.
>>>> 
>>>> &RBCS_PARM01
>>>> tauRelaxT=86400.,
>>>> tauRelaxS=86400.,
>>>> tauRelaxU=86400.,
>>>> 
>>>> rbcsForcingUPeriod=0.,
>>>> rbcsForcingUCycle=0.,
>>>> rbcsForcingUOffset=0.,
>>>> 
>>>> relaxMaskFile(1)='rbcsMask.bin',
>>>> relaxMaskFile(2)='rbcsMask.bin',
>>>> relaxMaskFile(3)='rbcsMask.bin',    
>>>> 
>>>> relaxTFile='rbcsT.bin',
>>>> relaxSFile='rbcsS.bin',
>>>> relaxUFile='rbcsU.bin',
>>>> 
>>>> relaxMaskUFile='rbcsMask.bin',
>>>> 
>>>> useRBCtemp=.TRUE.,
>>>> useRBCsalt=.TRUE.,
>>>> useRBCuVel=.TRUE.,
>>>> 
>>>> useRBCptracers=.TRUE.,
>>>> rbcsIniter=0.,
>>>> rbcsForcingPeriod=0.,
>>>> rbcsForcingCycle=0.,
>>>> &
>>>> 
>>>> &RBCS_PARM02
>>>> 
>>>> useRBCptrnum(1)    = .TRUE.,
>>>> tauRelaxPTR(1)     = 1200.,
>>>> relaxPtracerFile(1)='rbcsMask.bin',
>>>> 
>>>> &
>>>> 
>>>> Thanks for the help,
>>>> Dustin Carroll
>>>> 
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>>>> MITgcm-support at mitgcm.org
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>>> 
>>> 
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