From ae59beaec3e1c61ddb11184bfcf1a5d2863a2ca7 Mon Sep 17 00:00:00 2001 From: Peter Norris Date: Wed, 19 Jan 2022 17:43:04 -0500 Subject: [PATCH] pmn: simple fix to prevent negative tauaer in RRTMG LW --- .../GEOSirrad_GridComp/GEOS_IrradGridComp.F90 | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/GEOSagcm_GridComp/GEOSphysics_GridComp/GEOSradiation_GridComp/GEOSirrad_GridComp/GEOS_IrradGridComp.F90 b/GEOSagcm_GridComp/GEOSphysics_GridComp/GEOSradiation_GridComp/GEOSirrad_GridComp/GEOS_IrradGridComp.F90 index 48b52cc49..2daddb370 100644 --- a/GEOSagcm_GridComp/GEOSphysics_GridComp/GEOSradiation_GridComp/GEOSirrad_GridComp/GEOS_IrradGridComp.F90 +++ b/GEOSagcm_GridComp/GEOSphysics_GridComp/GEOSradiation_GridComp/GEOSirrad_GridComp/GEOS_IrradGridComp.F90 @@ -3283,7 +3283,11 @@ subroutine Lw_Driver(IM,JM,LM,LATS,LONS,CoresPerNode,RC) ! aerosol system's *un*-normalized single scattering albedo, ! which is actually tau_ext * omega0 = tau_scat, and TAUA ! is the aerosol extinction optical thickness. - TAUAER(IJ,K,:) = TAUA(I,J,LV,:) - SSAA(I,J,LV,:) + ! PMN 2022-01-19 Added max(,0.) ... it shouldn't happen + ! that tau_ext < tau_scat, but since these TAUA and SSAA + ! come directly from the radiatively active aerosols + ! system, we provide a simple mitigation here. + TAUAER(IJ,K,:) = max(TAUA(I,J,LV,:) - SSAA(I,J,LV,:), 0.) enddo