[Mitgcm-support] Re: convective adjustment

[mitgcm-support at dev.mitgcm.org]

Hi Sonya,

 At checkpoint 38

 cAdjFreq = -1 causes the frequency to be set
 to the model timestep.

 cAdjFreq = 0 stops it happening

 cAdjFreq = +NNN causes it to happen every NNN seconds.

 There are two forms of convective adjustment
 (1) mixing by averaging adjacent levels
 (2) mixing by high vertical diffusivity

 cAdjFreq controls (1)
   relevant code is
    convect.F
    convective_adjustment.F
    the_correction_step.F

 ivdc_Kappa controls (2) There is no way to set a frequency
 with 2. ivdc_Kappa is a high vertical diffusivity that will
 be used where adjacent vertical levels are unstable.
  relevant code is
   calc_ivdc.F
   impldiff.F
 (2) requires implicitDiffusion=.TRUE.

 (1) and (2) produce indistinguishable results!!!

Chris
Sonya Legg wrote:
> 
> Yes, I actually want to do some runs with convective adjustment!
> I've never used it before, so just want to check I know what I'm
> doing - is the only parameter I need to change cadjfreq?
> And that is a real time number, not number of timesteps?
> At the moment it's set to -1, I presume that means cadj never
> happens?
> 
> Thanks for help
> 
> Sonya