Surface latent heat flux Components in WRF-CLM

Hi,

I am using the CLM option in WRF for my land surface model (CLMv4 in WRFv3.9), and I am trying to look for the partitioning of latent heat flux into its component parts (i.e., bare soil evaporation, transpiration, etc.). CLM produces LHSOI, LHTRAN, LHVEG as variables that (I assume) would contain this information. However, each of these variables is only populated in the top three levels. These variables are 3 dimensional: lat, lon and something called "subgrid_stag". Subgrid_stag=10, which is the same as the number of soil layers. Am I correct in assuming that "subgrid_stag" refers to the soil layers?

If the third dimension of LHSOI,LHTRAN, and LHVEG is not depth, then does anyone know what it is referring to? Also, can anyone confirm that these variables (LHSOI, LHVEG, LHTRAN) contain the information that I am looking for?

Any advice is welcome.

Hi,
Yes, I believe you have the correct variables. If you look in the Registry/registry.clm file, you can see the descriptions for each of the variables. As for the subgrid_soil dimension, it does sound like it's likely the soil layers. Where are you actually seeing that name (subgrid_stag) though? In searching through the code, I'm unable to find it anywhere. Thanks!

Hi kwerner,

Thank you for the response.

I find it originally in the dimensions section of the model output:

dimensions:
Time = 1 // unlimited
DateStrLen = 19
west_east = 402
south_north = 297
bottom_top = 50
bottom_top_stag = 51
soil_layers_stag = 10
west_east_stag = 403
south_north_stag = 298
subgrid_stag = 10

Then I find it again as the dimensions for CLM specific variables (such as LHSOI, etc.):

float LHSOI ( Time, subgrid_stag, south_north, west_east )
FieldType : 104
MemoryOrder : XYZ
description : LH from soil
units : W/m^2
stagger : Z
coordinates : XLONG XLAT XTIME

float LHVEG ( Time, subgrid_stag, south_north, west_east )
FieldType : 104
MemoryOrder : XYZ
description : LH from vegetation
units : W/m^2
stagger : Z
coordinates : XLONG XLAT XTIME

float LHTRAN ( Time, subgrid_stag, south_north, west_east )
FieldType : 104
MemoryOrder : XYZ
description : LH from transpiration
units : W/m^2
stagger : Z
coordinates : XLONG XLAT XTIME

It only seems to occur when CLM is chosen as the LSM.

Thank you for your help!

EJD