about the usage of background brunt vasaila frequency

General scientific issues regarding ROMS

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leonjld
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about the usage of background brunt vasaila frequency

#1 Post by leonjld » Thu Nov 17, 2011 3:07 pm

hi, I have a case in which I want to change the stratification. will it make any difference if I change the BVF_BAK in the input file? will that value has any effect in the momentum equation? it seems from the code that BVF_BAK is only used in brunt-vasaila frequency dependent vertical mixing? just want to make sure.

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arango
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Re: about the usage of background brunt vasaila frequency

#2 Post by arango » Thu Nov 17, 2011 3:42 pm

No, this parameter is only used to scale the energy norm in adjoint-based algorithms for singular vectors and optimal perturbations. If you want to change the stratification in any ocean modeling application, you need to change the vertical gradients of density. That is, you need to change your initial conditions for temperature and salinity. There is not other way. You cannot control change easily of stratification via a vertical mixing parametrization because it involves nonlinear processes between ambient circulation and external forcing.

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Re: about the usage of background brunt vasaila frequency

#3 Post by Kun » Mon Apr 20, 2015 12:47 pm

arango wrote:No, this parameter is only used to scale the energy norm in adjoint-based algorithms for singular vectors and optimal perturbations. If you want to change the stratification in any ocean modeling application, you need to change the vertical gradients of density. That is, you need to change your initial conditions for temperature and salinity. There is not other way. You cannot control change easily of stratification via a vertical mixing parametrization because it involves nonlinear processes between ambient circulation and external forcing.
If I use the ROMS ADJOINT MODEL to do some work. Here is one problem: If I want use the energy norm for all kinds of perturbations, I know kinetic energy (involved with du dv) and gravitational potential energy (involved with dzeta). But how can deal with the dtemp and dsalt varibles in the energy norm in ROMS??

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