How to change Soil heat capacity, thermal diffusivity, thermal inertia

[water]

Hi, WRF support:
I want to change Soil heat capacity (C), thermal diffusivity (Kt), and thermal inertia (Iq), in such a way that they remain constant during the integration time. Where should I make these modifications, and what is the specific code?How to change the height of vertical soil layer? Is it in the namelist?

 

[Ming Chen]

It depends on what scheme you activate. Soil heat capacity (C) and thermal inertia are specified in LANDUSE.TBL. They are later read into the model and used by the SLAB scheme. You can find related code to read LANDUSE.TBL in phys/module_physics_init.F.

Calculation and modification of these variables depend on what schemes you use. For example, if you run with Noah LSM, thermal diffusivity is calculated in the subroutine "TDFCND" (see phys/module_sf_noahlsm.F). It is handled in a different way in RUC LSM, and you can find details in the subroutine "SOILPROP" of RUC LSM scheme.

By skipping the calculation of these variables, you can keep them unchanged. This will involve some coding work in the related codes.

Hope this is helpful for you.

 

[water]

It depends on what scheme you activate. Soil heat capacity (C) and thermal inertia are specified in LANDUSE.TBL. They are later read into the model and used by the SLAB scheme. You can find related code to read LANDUSE.TBL in phys/module_physics_init.F.

Calculation and modification of these variables depend on what schemes you use. For example, if you run with Noah LSM, thermal diffusivity is calculated in the subroutine "TDFCND" (see phys/module_sf_noahlsm.F). It is handled in a different way in RUC LSM, and you can find details in the subroutine "SOILPROP" of RUC LSM scheme.

By skipping the calculation of these variables, you can keep them unchanged. This will involve some coding work in the related codes.

Hope this is helpful for you.

Can I directly modify the F11 value in SOILPARM.TBL? Currently, the F11 for the soil type SILT LOAM is 0.162. What is the unit, and is it reasonable to change it to 2.84?

 

[Ming Chen]

Soil thermal diffusivity depends on soil type, density and water content, the range of values that can take is broad. However, I am not an expert in soil physics and have no idea whether 2.84 is a reasonable value. Please refer to the literature for more information.
If you only modify F11, it will change the diffusivity, but I don't think it will keep soil heat capacity unchanged during the integration.

 

[water]

Soil thermal diffusivity depends on soil type, density and water content, the range of values that can take is broad. However, I am not an expert in soil physics and have no idea whether 2.84 is a reasonable value. Please refer to the literature for more information.
If you only modify F11, it will change the diffusivity, but I don't think it will keep soil heat capacity unchanged during the integration.

I'm examining the code in module_sf_noahlsm.F, and I noticed that the program calls the thermal diffusivity using the parameter F11 from SOILPARM.TBL. Can you tell me other ways to modify the thermal diffusivity parameters? I'm conducting an ideal experiment and using the Noah LSM scheme.