Slab(Bulk) Scheme configurations

[sadeghnn]

Hello,
I am using Noah LSM(sf_surface_physics = 2) with Bulk Scheme (sf_urban_physics = 0) I want to change: roughness length, surface albedo,volumetric heat capacity, and thermal conductivity of urban and build up. I read WRF User's Guide and mentioned for Noah LSM we should change VEGPARM.TBL table, but all of these parameters are not available there. How can I do that? Thanks for helping me to figure it out.

 

[Ming Chen]

Please look at both VEGPARM.TBL and LANDSE.TBL, which includes these variables you are looking for.

 

[mgakinsola]

Please is there a way to determine/change roughness length for SLUCM; sf_urban_physics=1 and BEPBEM sf_urban_physics=3 as I am not sure these urban models use the VEGPARM.TBL and LANDUSE.TBL. The roughness lenght for ground and building available in the URBPARM.TBL is only valid for CH_SCHEME=1 , how can i determine/modify the roughness lenght when using CH_SCHEME=2

 

[Ming Chen]

If you run with urban physics module, then the roughness over urban area are specified in "URBPARM.TBL", in which you can find the variables Z0B, Z0G and Z0R. They are roughness length for momentum over building wall, roughness length for momentum over ground (road), and roughness length for momentum over roof, respectively. Please modify these variables in URBPARM.TBL.

 

[papayasalad]

If you run with urban physics module, then the roughness over urban area are specified in "URBPARM.TBL", in which you can find the variables Z0B, Z0G and Z0R. They are roughness length for momentum over building wall, roughness length for momentum over ground (road), and roughness length for momentum over roof, respectively. Please modify these variables in URBPARM.TBL.

I’m currently using gridded Urban Canopy Parameters (UCPs) in my WRF simulation and would like to clarify how the surface roughness length (Z0) is handled in this case.

If UCPs such as lp_urb!, stdh_urb!, frc_urb!, lb_urb!, lf_urb! are provided in a spatially distributed (grid-based) format, is the Z0 value internally calculated based on these UCPs for each grid cell? Or is Z0 still determined solely from the values defined in the URBPARM_LCZ.TBL for each LCZ or urban category?

Best regards
Dan Song

 

[Ming Chen]

Hi Dan,

Z0 is specified based on the urban category at each individual grid. Its value is given in URBPARM_LCZ.TBL. I don't think it has anything to do with those UCPs, while the UCPs may also depend on urban category.