Interpretation of heating rate output

[sean_m_davis@noaa_gov]

Is the heating rate output from WACCM the changein theta per unit time or the change in temperature per unit time?it's not clear from the netcdf meta data:

float HR(time, lev, lat, lon) ;
HR:mdims = 1 ;
HR:units = "K/s" ;
HR:long_name = "Heating rate needed for d(theta)/dt computation" ;
HR:cell_methods = "time: mean" ;

 

[mmills]

This is not a heating rate that we generally look at in WACCM runs. We use QRS_TOT for shortwave and QRL_TOT for longwave. You can have a look in the code at where HR is output. If you are using WACCM4, this is in cam/src/physics/cam/radiation.F90:    ! output rad inputs and resulting heating rates    call rad_data_write( pbuf, state, cam_in, coszrs )     ! Compute net radiative heating tendency    call radheat_tend(state, pbuf,  ptend, qrl, qrs, fsns, &                         fsnt, flns, flnt, cam_in%asdir, net_flx)     if (write_output) then       ! Compute heating rate for dtheta/dt       do k=1,pver          do i=1,ncol             ftem(i,k) = (qrs(i,k) + qrl(i,k))/cpair * (1.e5_r8/state%pmid(i,k))**cappa          end do       end do       call outfld('HR      ',ftem    ,pcols   ,lchnk   )    end if 

 

[mmills]

Be aware that the QRS and QRL components used in the HR calculation are not valid above about 50 km in WACCM. WACCM uses a non-LTE radiation code above 50 km. The merged heating rates are available as QRS_TOT and QRL_TOT.