[Mitgcm-support] Re: about AIM

[mitgcm-support at dev.mitgcm.org]

Hi Jean-Michel,

I'm not sure why FWIND0 is set to 0.42 but this is the value I always used. 
I believe the value was originally changed by Christophe Herbaut while he 
was working on AIM (before me) and doing some debugging (see the comment 
line cchdbg).

Daniel

At 05:31 PM 9/22/2002 -0400, Jean-Michel Campin wrote:
>Hi,
>
>I have few questions about AIM:
>(Daniel, if you have some idea about the 1rst one ...Thanks)
>
>1) Does any one remember why we set FWIND0 to .42 instead of
>the value Franco use in his paper (=0.6)
>It's set in INPHYS, line 118:
>
>C
>C---  3. Constants for surface fluxes (common SFLCON):
>C
>       FWIND0 = 0.6 _d 0
>cchdbg *****************************************************
>       FWIND0 = 0.6 _d 0*0.7 _d 0
>cchdbg ******************************************************
>
>Since FWIND0 is use to compute the wind at the surface from
>the wind at the 1rst level, and used after in the stress,
>this can contribute to the strong surface wind we found in the
>runs.
>
>2) with full-cell and no Shapiro on Q, the global average of P-E
>balance the surface correction term. The 2 are different by less
>than 10^-4 mm/day.
>
>3) Concerning Temperature, it does not work:
>the same run with full-cell and no Shapiro on theta :
>net heat flux (top) - (surface) = 0.9 W/m2  => warm the atmosphere
>surface correction on Theta     = 0.5 W/m2  => warm the atmosphere
>latent heat due to exess P-E    = 0.3 W/m2  => warm the atmosphere
>
>My impression is that there is a problem in Heat conservation:
>the dynamics conserves theta but the physics conserves the absolute
>temperature:
>If there is a radiative flux Fr from level 1 --> 2,
>   Cp*dT1 = -Fr ; Cp*dT2 = +Fr   ==> T is conserved.
>but
>   PI_1*dTheta_1= -Fr ; PI_2*dTheta_2 = +Fr  ==> Theta is not conserved
>because PI_1 & PI_2 are differents (PI = Cp*(p/Po)**kappa)
>
>And since the dynamics advects theta, only theta can be conserved,
>its my impression.
>
>4) for Chris: to put partial cell in AIM, can I start with the code in
>the repository or would be better to use the coupled version ?
>
>Jean-Michel