Blowing-up when using GLS turbulence closure

[Rocky_Wang]

Hello everyone,
I usually use the Mellor–Yamada Level 2.5 scheme in my model. Bnd when I try to use the GLS turbulence closure today, It always blowing-up after hundreds of time-steps. And I can not find the reason. I think the grid that I use is normal(I use this grid file for a longtime). I try to run the model only with tidal forcing (turn off sediment module, atmosphere and river forcing and so on in my model), decrease DT or increase NDTFAST, but they can't work. The attachment is my .h file and my log.dat file, I didn't change any GLS turbulence closure parameters in my .in file. Can you tell me the correct way to use GLS scheme?

[kate]

I see you went for the default K-epsilon GLS parameters. We should get input from the GLS folks about why they are the default. They have never worked for me, while the K-omega values do work (mostly):

Code: Select all

       GLS_P == -1.0d0                           ! K-omega
       GLS_M == 0.5d0
       GLS_N == -1.0d0
    GLS_Kmin == 7.6d-6
    GLS_Pmin == 1.0d-12

    GLS_CMU0 == 0.5477d0
      GLS_C1 == 0.555d0
      GLS_C2 == 0.833d0
     GLS_C3M == -0.6d0
     GLS_C3P == 1.0d0
    GLS_SIGK == 2.0d0
    GLS_SIGP == 2.0d0

[Rocky_Wang]

Thank you Kate! It works!

[bperfect]

Kate, as far as I can tell, the default GLS settings come from JC Warner's implementation of K-epsilon (Warner, Sherwood, Arango, 2005). Have you ever used the "gen" set of parameters? (P=2,M=1,N=-0.67)

[kate]

No, I've mostly gone back to LMD_MIXING now.

[Rocky_Wang]

Hello Kate,
I use the BULK_FLUXES in my model. My CPPDEFS options are :

# define BULK_FLUXES
# define ANA_BTFLUX
# define ANA_BSFLUX
# define ATM_PRESS
# define EMINUSP
# define SOLAR_SOURCE

and I download data from ERA-interim to make my forcing files. My variables are:

lwrad_down % downward longwave radiation flux W/m2
swrad % downward shortwave radiation flux W/m2
rain % precipitation rate kg/m2/s
Tair % surface air temperature K
Pair % pressure at surface Pa
Qair % relative_humidity
Winds % surface u-wind m/s


Recently, I find the sea water temperature that I simulated is higher than observation. And I have no idea which parameter I can change to improve the result. Is the temperature diffusion related to AKT_BAK or something else?

[kate]

You need to define LONGWAVE_OUT so that the model will compute the upward longwave. I hope that helps.