EXERCISE 6

Exercise 6: Using smoke tracers with a WRF-Chem run over Southeastern Asia

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Purpose: To familiarize the user with the using smoke tracers WRF simulation.

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1. Save the wrf output data file from any previous exercise by moving it to a file with a different name.

   mv wrfout_d01_2012-09-16_00:00:00 wrfout_d01_2012-09-16_save

   
   

2. Save the wrf input and boundar data files from any previous exercise by copying them to a file with a different name.

   cp wrfinput_d01 wrfinput_d01_save

   cp wrfbdy_d01 wrfinbdy_d01_save

   
   

3. If necessary, edit the module_input_tracer_data.F module inside the WRFV3/chem directory. This module is used to define the smoke tracers lateral boundary values. Look for "tr_smoke_values" which is the parameter that defines the tracer smoke value and set it to your desired background level. The default value in the release code is .08, but a value of 0. would be better for this tutorial exercise. Change the value of tr_smoke_value to zero and recompile WRF-Chem to apply the new parameter setting.

   REAL, PARAMETER:: tr_smoke_value=.0

   
   
4. Next, inside the chem directory is the program module_add_emiss_burn.F. The module_add_emiss_burn.F subroutine is used to set the smoke emissions input array and smoke tracers input values. Look for the "temiss_select" case statement for tracer_opt in the module. Here the CO biomass burning emissions (ebu_co) from the biomass burning structure (ebu) are used to provide the smoke emissions input. A user could define a different source for the smoke tracer by modifying chemistry values inside the do loop.

   temiss_select: SELECT CASE(tracer_opt)

   CASE (TRACER_SMOKE)

   !

   ! for smoke only

   !

   do j=jts,jte

   do i=its,ite

   do k=kts,kte

   conv_rho=r_q*4.828e-4/rho_phy(i,k,j)*dtstep/(dz8w(i,k,j)*60.)

   chem(i,k,j,p_smoke) = chem(i,k,j,p_smoke)+ebu(i,k,j,p_ebu_co)*conv_rho

   enddo

   enddo

   enddo

   
   

5. To run WRF-Chem with smoke tracers, set the tracer_opt in the dynamics section of the namelist.input file

   tracer_opt = 1,

   
   

6. Run real.exe for seven days to include dust (dust_opt=401) and smoke tracers (tracer_opt = 1). Since the smoke tracer input comes from the biomass burning data, be sure to have the auxiliary input port turned on as well (io_form_auxinput7 = 2) and a wrffirechemi_d01 data file in the WRFV3/test/em_real directory.

   
   

7. Run wrf.exe for seven days with dust (dust_opt=401) and smoke tracers (tracer_opt = 1).

   Examine the model results and look at the value of the smoke array.

   

This concludes WRF-Chem Southeastern Asia domain tutorial exercise 6

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