bug in the lidar simulator (COSP1.4 and COSP2)

Greg Cesana from GISS/Columbia Univ. recently reported a bug in the lidar simulator in COSP1.4 and COSP2. For COSP1.4, “snow” has been mistakenly added to liquid in COSP1.4. For COPS2, “snow” is not accounted for at all. This will have potentially large impact on cloud phase diagnostics from the lidar simulator. So we need to fix it.

For COSP2, to fix the bug, we only need to change the line 463-468 in cosp_optics.F90

from
betatot_ice(1:npoints,icol,1:nlev) = betatot_ice(1:npoints,icol,1:nlev)+ &
kp_part(1:npoints,1:nlev,INDX_LSICE)*alpha_part(1:npoints,1:nlev,INDX_LSICE)+ &
kp_part(1:npoints,1:nlev,INDX_CVICE)*alpha_part(1:npoints,1:nlev,INDX_CVICE)
tautot_ice(1:npoints,icol,1:nlev) = tautot_ice(1:npoints,icol,1:nlev) + &
tau_part(1:npoints,1:nlev,INDX_LSICE) + &
tau_part(1:npoints,1:nlev,INDX_CVICE)

to
betatot_ice(1:npoints,icol,1:nlev) = betatot_ice(1:npoints,icol,1:nlev)+ &
kp_part(1:npoints,1:nlev,INDX_LSICE)*alpha_part(1:npoints,1:nlev,INDX_LSICE)+ &
kp_part(1:npoints,1:nlev,INDX_CVICE)*alpha_part(1:npoints,1:nlev,INDX_CVICE)+ &
kp_part(1:npoints,1:nlev,INDX_LSSNOW)*alpha_part(1:npoints,1:nlev,INDX_LSSNOW)
tautot_ice(1:npoints,icol,1:nlev) = tautot_ice(1:npoints,icol,1:nlev) + &
tau_part(1:npoints,1:nlev,INDX_LSICE) + &
tau_part(1:npoints,1:nlev,INDX_CVICE) + &
tau_part(1:npoints,1:nlev,INDX_LSSNOW)

For COSP1.4, we need to change the line 484-491 in lidar_simulator.F90

from
DO i = 2, npart,2
betatot_ice(:,:) = betatot_ice(:,:)+ kp_part(:,:,i)*alpha_part(:,:,i)
tautot_ice(:,:) = tautot_ice(:,:) + tau_part(:,:,i)
ENDDO ! i
DO i = 1, npart,2
betatot_liq(:,:) = betatot_liq(:,:)+ kp_part(:,:,i)*alpha_part(:,:,i)
tautot_liq(:,:) = tautot_liq(:,:) + tau_part(:,:,i)
ENDDO ! i

to
DO i = 2, npart,2
betatot_ice(:,:) = betatot_ice(:,:)+ kp_part(:,:,i)*alpha_part(:,:,i)
tautot_ice(:,:) = tautot_ice(:,:) + tau_part(:,:,i)
ENDDO ! i
betatot_ice(:,:) = betatot_ice(:,:)+ kp_part(:,:,5)*alpha_part(:,:,5)
tautot_ice(:,:) = tautot_ice(:,:) + tau_part(:,:,5)
DO i = 1, npart-1,2
betatot_liq(:,:) = betatot_liq(:,:)+ kp_part(:,:,i)*alpha_part(:,:,i)
tautot_liq(:,:) = tautot_liq(:,:) + tau_part(:,:,i)
ENDDO ! i

Yuying Zhang (LLNL)