<p>Well I can see one major reason the dry deposition is not working- the namelist variable for gas deposition (gas_drydep_opt) is turned off. I am not entirely sure how the wet deposition works, though my guess is that it only applies to aerosols, so you would need to turn on wet scavenging for non-zero values.</p>
<p><a href="https://ruc.noaa.gov/wrf/wrf-chem/Users_guide.pdf" rel="nofollow noreferrer">Some of the documentation</a> implies that wet deposition only applies to certain chemical mechanisms and for certain chemicals. This is probably the reason you aren't getting any wet deposition.</p>

CC BY-SA 4.0
2021-06-01T06:10:16.590Z
Thanks for the response, I shall tell you that I am working with chem_opt=17(GHG: greenhouse gases option) and I put the wet scavenging for non-zero values too, but the model showed this error: "wet scav_onoff" option requires chem_opt=8,13,36 to 41,42,503,504,601,611".
sara
CC BY-SA 4.0
2021-06-01T06:10:21.420Z
then I had to put the value of "wet scav_onoff" and "cldchem_onoff" to zero value again , and put the value of gas_drydep_opt to 1. after all run the model by this condition for 24 hours. today I checked the wrf outpout files and saw that the dry_dep_flux and wet_dep_flux are zero again and understood that "gas_drydep_opt" doesn't affect  dry_dep_flux values!!!.
sara
CC BY-SA 4.0
2021-06-01T14:36:13.263Z
Yes, the wet scavenging applies for aerosols (certain chemical mechanisms and certain chemicals). Admittedly I overlooked that it is WRF_GHG you are using and not WRF-Chem. But chem_opt=17 is probably the WRF-Chem tracer option which is not subject to dry deposition per page 4 of the [user guide](https://www.bgc-jena.mpg.de/bgc-systems/pmwiki2/uploads/Download/Wrf-ghg/WRF-GHG_Techn_Report.pdf). What you are looking for is probably chem_opt=98, per page 36. Note this is not one of the options for wet scavenging, that is because scavenging is used more for aerosols.
BarocliniCplusplus
CC BY-SA 4.0
2021-06-02T19:54:42.647Z
Thank you dear BarocliniCplusplus, then I have to give up everything about dry_dep and wet_dep with this chem_opt=17or 16. Thanks for the response :)
sara
CC BY-SA 4.0
2021-05-31T14:11:11.137Z
2021-05-31T14:11:11.137Z
BarocliniCplusplus
<p>I am working on WRF_GHG, I would like to calculate dry and wet deposition in the dry and wet seasons for CO<sub>2</sub> and CH<sub>4</sub> gases. However, when I check the wrf output, I see that all the variables (DRY_DEP_FLUX and WET_DEP_FLUX) are zero in all the time steps.</p>
<p>I've attached my namelist.input link too.</p>
<p><a href="https://drive.google.com/file/d/1JS6Y77EIk0XQ3BzwHXGDH2BRk9b5rwgV/view?usp=sharing" rel="nofollow noreferrer">https://drive.google.com/file/d/1JS6Y77EIk0XQ3BzwHXGDH2BRk9b5rwgV/view?usp=sharing</a></p>
<p>What causes my mistake?</p>
<p>Could I possibly ask you to check it please? Do you know why I get the wrong zero values for two of those variables (DRY_DEP_FLUX and WET_DEP_FLUX)?</p>

<meteorology><weather-forecasting><numerical-modelling><wrf><wrf-chem>
Why are all the variables ( DRY_DEP_FLUX and WET_DEP_FLUX) zero in a wrf model output in all the time steps
sara
# Why are all the variables ( DRY_DEP_FLUX and WET_DEP_FLUX) zero in a wrf model output in all the time steps

(Asked by: username_0 on 2021-05-30)

I am working on WRF\_GHG, I would like to calculate dry and wet deposition in the dry and wet seasons for CO2 and CH4 gases. However, when I check the wrf output, I see that all the variables (DRY\_DEP\_FLUX and WET\_DEP\_FLUX) are zero in all the time steps.

I've attached my namelist.input link too.

<https://drive.google.com/file/d/1JS6Y77EIk0XQ3BzwHXGDH2BRk9b5rwgV/view?usp=sharing>

What causes my mistake?

Could I possibly ask you to check it please? Do you know why I get the wrong zero values for two of those variables (DRY\_DEP\_FLUX and WET\_DEP\_FLUX)?

**Tags:** meteorology, weather-forecasting, numerical-modelling, wrf, wrf-chem


---

## 1 answers

### Answer by username_1 on 2021-05-31. Score: 1

Well I can see one major reason the dry deposition is not working- the namelist variable for gas deposition (gas\_drydep\_opt) is turned off. I am not entirely sure how the wet deposition works, though my guess is that it only applies to aerosols, so you would need to turn on wet scavenging for non-zero values.

[Some of the documentation](https://ruc.noaa.gov/wrf/wrf-chem/Users_guide.pdf) implies that wet deposition only applies to certain chemical mechanisms and for certain chemicals. This is probably the reason you aren't getting any wet deposition.

> **Comments:**
> **username_0**: Thanks for the response, I shall tell you that I am working with chem_opt=17(GHG: greenhouse gases option) and I put the wet scavenging for non-zero values too, but the model showed this error: "wet scav_onoff" option requires chem_opt=8,13,36 to 41,42,503,504,601,611".  
> **username_0**: then I had to put the value of "wet scav_onoff" and "cldchem_onoff" to zero value again , and put the value of gas_drydep_opt to 1. after all run the model by this condition for 24 hours. today I checked the wrf outpout files and saw that the dry_dep_flux and wet_dep_flux are zero again and understood that "gas_drydep_opt" doesn't affect  dry_dep_flux values!!!.  
> **username_1**: Yes, the wet scavenging applies for aerosols (certain chemical mechanisms and certain chemicals). Admittedly I overlooked that it is WRF_GHG you are using and not WRF-Chem. But chem_opt=17 is probably the WRF-Chem tracer option which is not subject to dry deposition per page 4 of the [user guide](https://www.bgc-jena.mpg.de/bgc-systems/pmwiki2/uploads/Download/Wrf-ghg/WRF-GHG_Techn_Report.pdf). What you are looking for is probably chem_opt=98, per page 36. Note this is not one of the options for wet scavenging, that is because scavenging is used more for aerosols.  
> **username_0**: Thank you dear username_1, then I have to give up everything about dry_dep and wet_dep with this chem_opt=17or 16. Thanks for the response :)  

---

