From 34865fad5f70c03dd064f9d29827a4ecbc1c6831 Mon Sep 17 00:00:00 2001 From: Robert Hallberg Date: Sat, 20 Jan 2024 06:06:38 -0500 Subject: [PATCH] (*)Avoid using RHO_0 in non-Boussinesq averaging Use GV%H_to_MKS instead of GV%H_to_m when undoing the dimensional rescaling of thicknesses when taking weighted averages in horizontally_average_diag_field, global_layer_mean and global_volume_mean. In Boussinesq mode, these are identical, but in non-Boussinesq mode using GV%H_to_m introduced a multiplication and then division by the Boussinesq reference density, whereas GV%H_to_MKS avoids this by rescaling to a volume or mass-based coordinate depending on the mode. Several comments were also updated to reflect these conditional changes in the units of some internal variables. All expressions are mathematically equivalent, and this does not impact any solutions, but there can be changes in the last bits in some non-Boussinesq averaged diagnostics. --- src/diagnostics/MOM_spatial_means.F90 | 20 +++++++++++--------- src/framework/MOM_diag_remap.F90 | 17 ++++++++++++----- 2 files changed, 23 insertions(+), 14 deletions(-) diff --git a/src/diagnostics/MOM_spatial_means.F90 b/src/diagnostics/MOM_spatial_means.F90 index ab1210c0f5..60ad8dfba5 100644 --- a/src/diagnostics/MOM_spatial_means.F90 +++ b/src/diagnostics/MOM_spatial_means.F90 @@ -211,11 +211,13 @@ function global_layer_mean(var, h, G, GV, scale, tmp_scale) ! Local variables ! In the following comments, [A] is used to indicate the arbitrary, possibly rescaled units of the ! input array while [a] indicates the unscaled (e.g., mks) units that can be used with the reproducing sums - real, dimension(G%isc:G%iec,G%jsc:G%jec,SZK_(GV)) :: tmpForSumming ! An unscaled cell integral [a m3] - real, dimension(G%isc:G%iec,G%jsc:G%jec,SZK_(GV)) :: weight ! The volume of each cell, used as a weight [m3] + real, dimension(G%isc:G%iec,G%jsc:G%jec,SZK_(GV)) :: tmpForSumming ! An unscaled cell integral [a m3] or [a kg] + real, dimension(G%isc:G%iec,G%jsc:G%jec,SZK_(GV)) :: weight ! The volume or mass of each cell, depending on + ! whether the model is Boussinesq, used as a weight [m3] or [kg] type(EFP_type), dimension(2*SZK_(GV)) :: laysums - real, dimension(SZK_(GV)) :: global_temp_scalar ! The global integral of the tracer in each layer [a m3] - real, dimension(SZK_(GV)) :: global_weight_scalar ! The global integral of the volume of each layer [m3] + real, dimension(SZK_(GV)) :: global_temp_scalar ! The global integral of the tracer in each layer [a m3] or [a kg] + real, dimension(SZK_(GV)) :: global_weight_scalar ! The global integral of the volume or mass of each + ! layer [m3] or [kg] real :: temp_scale ! A temporary scaling factor [a A-1 ~> 1] or [1] real :: scalefac ! A scaling factor for the variable [a A-1 ~> 1] integer :: i, j, k, is, ie, js, je, nz @@ -226,7 +228,7 @@ function global_layer_mean(var, h, G, GV, scale, tmp_scale) tmpForSumming(:,:,:) = 0. ; weight(:,:,:) = 0. do k=1,nz ; do j=js,je ; do i=is,ie - weight(i,j,k) = (GV%H_to_m * h(i,j,k)) * (G%US%L_to_m**2*G%areaT(i,j) * G%mask2dT(i,j)) + weight(i,j,k) = (GV%H_to_MKS * h(i,j,k)) * (G%US%L_to_m**2*G%areaT(i,j) * G%mask2dT(i,j)) tmpForSumming(i,j,k) = scalefac * var(i,j,k) * weight(i,j,k) enddo ; enddo ; enddo @@ -262,9 +264,9 @@ function global_volume_mean(var, h, G, GV, scale, tmp_scale) ! input array while [a] indicates the unscaled (e.g., mks) units that can be used with the reproducing sums real :: temp_scale ! A temporary scaling factor [a A-1 ~> 1] or [1] real :: scalefac ! A scaling factor for the variable [a A-1 ~> 1] - real :: weight_here ! The volume of a grid cell [m3] - real, dimension(SZI_(G),SZJ_(G)) :: tmpForSumming ! The volume integral of the variable in a column [a m3] - real, dimension(SZI_(G),SZJ_(G)) :: sum_weight ! The volume of each column of water [m3] + real :: weight_here ! The volume or mass of a grid cell [m3] or [kg] + real, dimension(SZI_(G),SZJ_(G)) :: tmpForSumming ! The volume integral of the variable in a column [a m3] or [a kg] + real, dimension(SZI_(G),SZJ_(G)) :: sum_weight ! The volume or mass of each column of water [m3] or [kg] integer :: i, j, k, is, ie, js, je, nz is = G%isc ; ie = G%iec ; js = G%jsc ; je = G%jec ; nz = GV%ke @@ -273,7 +275,7 @@ function global_volume_mean(var, h, G, GV, scale, tmp_scale) tmpForSumming(:,:) = 0. ; sum_weight(:,:) = 0. do k=1,nz ; do j=js,je ; do i=is,ie - weight_here = (GV%H_to_m * h(i,j,k)) * (G%US%L_to_m**2*G%areaT(i,j) * G%mask2dT(i,j)) + weight_here = (GV%H_to_MKS * h(i,j,k)) * (G%US%L_to_m**2*G%areaT(i,j) * G%mask2dT(i,j)) tmpForSumming(i,j) = tmpForSumming(i,j) + scalefac * var(i,j,k) * weight_here sum_weight(i,j) = sum_weight(i,j) + weight_here enddo ; enddo ; enddo diff --git a/src/framework/MOM_diag_remap.F90 b/src/framework/MOM_diag_remap.F90 index ff0eda6325..a2ecc197bc 100644 --- a/src/framework/MOM_diag_remap.F90 +++ b/src/framework/MOM_diag_remap.F90 @@ -658,8 +658,15 @@ subroutine horizontally_average_diag_field(G, GV, h, staggered_in_x, staggered_i logical, dimension(:), intent(inout) :: averaged_mask !< Mask for horizontally averaged field [nondim] ! Local variables - real, dimension(G%isc:G%iec, G%jsc:G%jec, size(field,3)) :: volume, stuff - real, dimension(size(field, 3)) :: vol_sum, stuff_sum ! nz+1 is needed for interface averages + real :: volume(G%isc:G%iec, G%jsc:G%jec, size(field,3)) ! The area [m2], volume [m3] or mass [kg] of each cell. + real :: stuff(G%isc:G%iec, G%jsc:G%jec, size(field,3)) ! The area, volume or mass-weighted integral of the + ! field being averaged in each cell, in [m2 A], [m3 A] or [kg A], + ! depending on the weighting for the averages and whether the + ! model makes the Boussinesq approximation. + real, dimension(size(field, 3)) :: vol_sum ! The global sum of the areas [m2], volumes [m3] or mass [kg] + ! in the cells that used in the weighted averages. + real, dimension(size(field, 3)) :: stuff_sum ! The global sum of the weighted field in all cells, in + ! [A m2], [A m3] or [A kg] type(EFP_type), dimension(2*size(field,3)) :: sums_EFP ! Sums of volume or stuff by layer real :: height ! An average thickness attributed to an velocity point [H ~> m or kg m-2] integer :: i, j, k, nz @@ -688,7 +695,7 @@ subroutine horizontally_average_diag_field(G, GV, h, staggered_in_x, staggered_i I1 = i - G%isdB + 1 height = 0.5 * (h(i,j,k) + h(i+1,j,k)) volume(I,j,k) = (G%US%L_to_m**2 * G%areaCu(I,j)) & - * (GV%H_to_m * height) * G%mask2dCu(I,j) + * (GV%H_to_MKS * height) * G%mask2dCu(I,j) stuff(I,j,k) = volume(I,j,k) * field(I1,j,k) enddo ; enddo endif @@ -717,7 +724,7 @@ subroutine horizontally_average_diag_field(G, GV, h, staggered_in_x, staggered_i J1 = J - G%jsdB + 1 height = 0.5 * (h(i,j,k) + h(i,j+1,k)) volume(i,J,k) = (G%US%L_to_m**2 * G%areaCv(i,J)) & - * (GV%H_to_m * height) * G%mask2dCv(i,J) + * (GV%H_to_MKS * height) * G%mask2dCv(i,J) stuff(i,J,k) = volume(i,J,k) * field(i,J1,k) enddo ; enddo endif @@ -748,7 +755,7 @@ subroutine horizontally_average_diag_field(G, GV, h, staggered_in_x, staggered_i else ! Intensive do j=G%jsc, G%jec ; do i=G%isc, G%iec volume(i,j,k) = (G%US%L_to_m**2 * G%areaT(i,j)) & - * (GV%H_to_m * h(i,j,k)) * G%mask2dT(i,j) + * (GV%H_to_MKS * h(i,j,k)) * G%mask2dT(i,j) stuff(i,j,k) = volume(i,j,k) * field(i,j,k) enddo ; enddo endif