GOCART AFWA dust_opt=3

Dear WRFChem users,

Is anyone else using dust_opt=3?
In wrfout there is a variable called UST_T (threshold frictional velocity) and our values currently show as zero.
I suspect this is causing us to generate dust continuously as U* > U*t.
Is anyone else experiencing the same issue?

from registry.chem
# soiltexturef is texture category fraction for each grid cell
state real ust_t ij misc 1 - i012rh "UST_T" "Threshold Friction Velocity" "m s-1"

Running WRFv3.9
Thanks and regards
Michael

The dust emission is calculated correctly with dust_opt = 3. The UST_T values are not written in output file by default so you see zero values. You need to modify the FORTRAN codes to output this variable if you need.