From e4d291e1b08ab68a7820f55921d0b5584d58944b Mon Sep 17 00:00:00 2001 From: tanyasmirnova Date: Fri, 1 Nov 2019 16:47:58 +0000 Subject: [PATCH] This commit has a fix for a problem of cloud-radiation coupling with the use of MYNN PBL. The problem: the first call to the radiation happens before the first call to MYNN PBL, therefore CLDFRA_BL=0 in the first call to mynnrad_pre, and zero values are sent to array cldcov(:,:). When cloud cover is zero, the RRTMG radiation thinks that there are no clouds at all. The erroneous cloud-free LW and SW downward radiation fluxes affect the first hour of itegration, and cause siginificant cooling in the ploar regions, and too warm land surface temperature from cloud-free SW radiation. The fix: the fist call to mynnrad_pre should be skipped, so that cloud cover - cldcov(:,:) - is not overwritten by zero values of MYNN subgrid-clouds. In this case the initial cloud cover is computed in progcld5 from initial cloud water mixing ratio, relative humidity and specific humidity in the layer. Starting with the second call to the rrtmg radiation, the MYNN subgrid clouds are used. --- physics/module_MYNNrad_post.F90 | 7 +++++++ physics/module_MYNNrad_post.meta | 16 ++++++++++++++++ physics/module_MYNNrad_pre.F90 | 8 +++++++- physics/module_MYNNrad_pre.meta | 16 ++++++++++++++++ 4 files changed, 46 insertions(+), 1 deletion(-) diff --git a/physics/module_MYNNrad_post.F90 b/physics/module_MYNNrad_post.F90 index 7acd2e406..1364db62e 100644 --- a/physics/module_MYNNrad_post.F90 +++ b/physics/module_MYNNrad_post.F90 @@ -22,6 +22,7 @@ end subroutine mynnrad_post_finalize #endif SUBROUTINE mynnrad_post_run( & & ix,im,levs, & + & flag_init,flag_restart, & & qc,qi, & & qc_save, qi_save, & & errmsg, errflg ) @@ -34,6 +35,7 @@ SUBROUTINE mynnrad_post_run( & !------------------------------------------------------------------- integer, intent(in) :: ix, im, levs + logical, intent(in) :: flag_init, flag_restart real(kind=kind_phys), dimension(im,levs), intent(out) :: qc, qi real(kind=kind_phys), dimension(im,levs), intent(in) :: qc_save, qi_save character(len=*), intent(out) :: errmsg @@ -48,6 +50,11 @@ SUBROUTINE mynnrad_post_run( & !write(0,*)"==============================================" !write(0,*)"in mynn rad post" + if (flag_init .and. (.not. flag_restart)) then + !write (0,*) 'Skip MYNNrad_post flag_init = ', flag_init + return + endif + ! Add subgrid cloud information: do k = 1, levs do i = 1, im diff --git a/physics/module_MYNNrad_post.meta b/physics/module_MYNNrad_post.meta index b09abe01e..881a19fff 100644 --- a/physics/module_MYNNrad_post.meta +++ b/physics/module_MYNNrad_post.meta @@ -25,6 +25,22 @@ type = integer intent = in optional = F +[flag_init] + standard_name = flag_for_first_time_step + long_name = flag signaling first time step for time integration loop + units = flag + dimensions = () + type = logical + intent = in + optional = F +[flag_restart] + standard_name = flag_for_restart + long_name = flag for restart (warmstart) or coldstart + units = flag + dimensions = () + type = logical + intent = in + optional = F [qc] standard_name = cloud_condensed_water_mixing_ratio long_name = moist (dry+vapor, no condensates) mixing ratio of cloud water (condensate) diff --git a/physics/module_MYNNrad_pre.F90 b/physics/module_MYNNrad_pre.F90 index 858abebee..95dc95445 100644 --- a/physics/module_MYNNrad_pre.F90 +++ b/physics/module_MYNNrad_pre.F90 @@ -32,6 +32,7 @@ end subroutine mynnrad_pre_finalize !###=================================================================== SUBROUTINE mynnrad_pre_run( & & ix,im,levs, & + & flag_init,flag_restart, & & qc, qi, T3D, & & qc_save, qi_save, & & qc_bl,cldfra_bl, & @@ -50,6 +51,7 @@ SUBROUTINE mynnrad_pre_run( & ! Interface variables real (kind=kind_phys), parameter :: gfac=1.0e5/con_g integer, intent(in) :: ix, im, levs + logical, intent(in) :: flag_init, flag_restart real(kind=kind_phys), dimension(im,levs), intent(inout) :: qc, qi real(kind=kind_phys), dimension(im,levs), intent(in) :: T3D,delp real(kind=kind_phys), dimension(im,levs), intent(inout) :: & @@ -71,13 +73,17 @@ SUBROUTINE mynnrad_pre_run( & !write(0,*)"==============================================" !write(0,*)"in mynn rad pre" + if (flag_init .and. (.not. flag_restart)) then + !write (0,*) 'Skip MYNNrad_pre flag_init = ', flag_init + return + endif ! Add subgrid cloud information: do k = 1, levs do i = 1, im qc_save(i,k) = qc(i,k) qi_save(i,k) = qi(i,k) - clouds1(i,k)=CLDFRA_BL(i,k) + clouds1(i,k) = CLDFRA_BL(i,k) IF (qc(i,k) < 1.E-6 .AND. qi(i,k) < 1.E-8 .AND. CLDFRA_BL(i,k)>0.001) THEN !Partition the BL clouds into water & ice according to a linear diff --git a/physics/module_MYNNrad_pre.meta b/physics/module_MYNNrad_pre.meta index 617ee3f31..3b5943c66 100644 --- a/physics/module_MYNNrad_pre.meta +++ b/physics/module_MYNNrad_pre.meta @@ -25,6 +25,22 @@ type = integer intent = in optional = F +[flag_init] + standard_name = flag_for_first_time_step + long_name = flag signaling first time step for time integration loop + units = flag + dimensions = () + type = logical + intent = in + optional = F +[flag_restart] + standard_name = flag_for_restart + long_name = flag for restart (warmstart) or coldstart + units = flag + dimensions = () + type = logical + intent = in + optional = F [qc] standard_name = cloud_condensed_water_mixing_ratio long_name = moist (dry+vapor, no condensates) mixing ratio of cloud water (condensate)