[MITgcm-support] hfac question

[Matthew Mazloff]

Hi David,

It is a bit odd that it gave you 90 for hFacW(1,:), but I guess it is  
fine as I believe what happens on the western open boundary is that it  
sets U(1,:) and U(2,:) to the prescribed value and sets (assumes) zero  
divergence right on the boundary center (helps pressure solver).  So  
yes, I believe what is truly coming into the dynamics -- and what is  
entering the domain -- is sum(U(2,:).*drF .* hfacW(2,:)).

-Matt


On Oct 6, 2009, at 8:56 AM, David Hebert wrote:

> Hi Matt,
>
> The point I mentioned is a W boundary point (should  have noted that  
> before, sorry). All surrounding points  are  also 100m. I do note  
> that the Eastern boundary is 90m. So if hFacW will obtain depth on  
> Eastern bounary is there something different I should do on the  
> West? i.e., seems I should use hFacW(2,:)?
>
> Thanks
>
> David
>
> On 10/06/09 10:49, Matthew Mazloff wrote:
>>
>> Hi David,
>>
>> This is correct.  You must have sloping topography and the depth at  
>> the west side of the cell is 90m, while its 100m in the center.  U  
>> is calculated on the west face, so the total volume transport is
>> sum(U(1,:).*drF .* hfacW(1,:)).
>>
>> Likewise one should use hFacS for V transport.
>>
>> -Matt
>>
>>
>> On Oct 6, 2009, at 8:38 AM, David Hebert wrote:
>>
>>> Hi all,
>>>
>>> I am attempting to balance barotropic inflow/outflow on the  
>>> boundaries of a 2D simulation. I ran the model one timestep to  
>>> obtain the hFac's in order to more accurately determine the depth  
>>> the model uses. The result from Depth.data at one point is 100m.
>>>
>>> In order to balance U, according to manual, I would use hFacW. I  
>>> get a very different result if I do sum(drF * hFacW). Results from  
>>> matlab (for 2D hFac's)...
>>>
>>> sum(drF .* hfacW(1,:)) = 90
>>> sum(drF .* hfacC(1,:)) = 100
>>>
>>> Seems I don't quite understand hfacW. Any ideas on what I did  
>>> wrong here?
>>>
>>> Thanks
>>>
>>> David
>>>
>>>
>>> _______________________________________________
>>> MITgcm-support mailing list
>>> MITgcm-support at mitgcm.org
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>>
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>
> -- 
> David A. Hebert
> NRC Postdoc
> Naval Research Lab
> Stennis Space Center, MS 39529
> david.hebert.ctr at nrlssc.navy.mil
> Phone: (228) 688-5846
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