Theta tendency due to radiation and aer_ra_feedback

[mikkolaj]

Hello,

Im working on idealised WRF-CHEM simulations using the ideal case em_les. To separate the impact of aerosol direct effect on meteorology and transport of aerosol, I use the namelist option aer_ra_feedback . This way I can still study the transport of aerosols even for the case with direct effect off (instead of setting the concentrations to zero).

Variable RTHRATENSW - UNCOUPLED THETA TENDENCY DUE TO SHORT WAVE RADIATION would be useful in my use case. However, the variable seem to have similar values for both cases aer_ra_feedback=1 and aer_ra_feedback=0. I have tried extreme high concentrations to test if the aerosol effect would have been just very small, which does not seem to be the case. The difference in the response of the meteorological fields is logical between these cases, so the namelist option aer_ra_feedback should act properly.

Do these output variables take to account the aer_ra_feedback or do they care only for the concentrations of the aerosol compounds? Is there a straightforward way to output the heating rate due to aerosols in SW scheme? I have also tried the output variables of opt_pars_out=1, extcof3 etc, but they seem to have the same problem.

I use WRF-Chem V4.4.1 with RRTMG radiation scheme and chem_opt=300 GOCART simple aerosol scheme. I initialize the run with idealised black carbon vertical profile and do not have any emissions during the simulation. Dry deposition for aerosols is switched on, otherwise the aerosol chemistry is switched off. Chemical compounds other than black carbon are initialized as zero.

Thanks for the help,
Johannes Mikkola