[MITgcm-support] Bulk formula package and wind stress

[Martin Losch]

Hi Océane,

I have no experience with pkg/bulk_force, but I would assume that the stress specified in data&PARAM05 will not be used in your case. The code e.g. in bulkf_formula_lanl.F looks very similar to the exf package (in fact it looks like a copy). I don’t know what the advantage of pkg/bulkf_force is over that of pkg/exf. The latter is probably more flexible in terms of specifying different fields with different forcing periods etc. (and you need pkg/exf if you want to use pkg/seaice)

Martin

> On 5. Nov 2019, at 06:02, Richet, Oceane (O&A, Hobart) <Oceane.Richet at csiro.au> wrote:
> 
> Hi Martin,
> 
> Thank you for your answer. Actually, I don't use the EXF package to calculate the bulk formula but directly the bulk_force package with wind vectors. But it should be similar to the EXF package. 
> 
> Just to give you a quick summary of what I have done. Before to implement the bulk formula, I was relaxing the fields at the surface and driving the ocean with wind stress vectors (PARM05 in data). Now, because I wanted to use the bulk_force package I added the wind vectors as input files (in data.blk) for the bulk formula calculation but with what you were saying, it looks redundant because the wind stress is directly calculated via the bulk_force package and then used to drive the ocean. Which means that I don't need anymore to have the wind stress vectors in data to drive my ocean - the wind (wind or wind stress vectors) is now only read via the bulk_force package (data.blk). Is it correct?
> 
> Does it change something to use the bulk_force package instead of the exf package?
> 
> Thank you,
> 
> Océane Richet
> CSHOR Postdoctoral Fellow 
> CSIRO, Hobart, Australia
> From: MITgcm-support <mitgcm-support-bounces at mitgcm.org> on behalf of Martin Losch <Martin.Losch at awi.de>
> Sent: Friday, November 1, 2019 6:54 PM
> To: MITgcm Support <mitgcm-support at mitgcm.org>
> Subject: Re: [MITgcm-support] Bulk formula package and wind stress
>  
> Hi Océane,
> 
> the wind stress (vector) will also drive the ocean circulation. Depending on your parameter setting, the input to exf_bulkformulae are wind vectors, wind speed (and sometimes wStress). wind speed sh (and sometimes wind stress wStress) have been computed in exf_wind, again depending on your parameter settings and CPP-flags. exf_bulkformulae then computes the turbulent fluxes and also the wind stress vector (uStress, vStress) at the end of the routine.
> 
> The routine is a little complicated because it depends on what you want to specify. In other words, if you have the model read precomputed stress vectors, then these will be used to drive the ocean, to derive some wStress and then compute the turbulent fluxes. If you use wind vectors to drive the model, then exf_bulkformulae will also compute the stress vector that drives the ocean.
> 
> Martin 
> 
> > On 31. Oct 2019, at 05:38, Richet, Oceane (O&A, Hobart) <Oceane.Richet at csiro.au> wrote:
> > 
> > Hi all,
> > 
> > I have a quick question. I am using the bulk formula package and I would like to know if the wind stress is only used for the bulk formula calculation or also as an external forcing.
> > 
> > Thank you,
> > 
> > Océane Richet
> > CSHOR Postdoctoral Fellow 
> > CSIRO, Hobart, Australia
> > _______________________________________________
> > MITgcm-support mailing list
> > MITgcm-support at mitgcm.org
> > http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support
> 
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