Merge pull request #3721 from CliMA/as/diff-mass-terms

exclude contributions from condensate, precip diffusion in mass tendency

Author: akshaysridhar

NEWS.md

@@ -12,6 +12,12 @@ removed from the configurable options.
 v0.29.1
 -------
 
+### Remove contribution from condensate, precip diffusion in mass tendency
+PR[#3721](https://github.com/CliMA/ClimaAtmos.jl/pull/3721)
+Diffusion of condensate (liq, ice) and precip (rai, sno) vars no longer 
+contributes to the mass tendency terms (updates in vert diffusion boundary layer,
+smag-lilly, implicit solver terms)
+
 ### Add support for non-zero `t_start`
 
 Passing a non zero `t_start` is useful in conditions where one wants to have a

src/parameterized_tendencies/les_sgs_models/smagorinsky_lilly.jl

@@ -166,7 +166,7 @@ function vertical_smagorinsky_lilly_tendency!(Yₜ, Y, p, t, ::SmagorinskyLilly)
         ᶜ∇ᵥρD∇χₜ = @. ᶜtemp_scalar = ᶜdivᵥ_ρχ(-(ᶠρ * ᶠD_smag * ᶠgradᵥ(ᶜχ)))
         @. ᶜρχₜ -= ᶜ∇ᵥρD∇χₜ
         # Rain and snow does not affect the mass
-        if χ_name ∉ (:q_rai, :q_sno)
+        if χ_name == :q_tot
             @. Yₜ.c.ρ -= ᶜ∇ᵥρD∇χₜ
         end
     end

src/prognostic_equations/hyperdiffusion.jl

@@ -295,7 +295,12 @@ NVTX.@annotate function apply_tracer_hyperdiffusion_tendency!(Yₜ, Y, p, t)
             ν₄_scalar,
         )
         @. ᶜρχₜ -= ν₄_scalar * wdivₕ(Y.c.ρ * gradₕ(ᶜ∇²χ))
-        @. Yₜ.c.ρ -= ν₄_scalar * wdivₕ(Y.c.ρ * gradₕ(ᶜ∇²χ))
+
+        # Exclude contributions from hyperdiffusion of condensate, 
+        # precipitating species from mass tendency. 
+        if χ_name == :q_tot
+            @. Yₜ.c.ρ -= ν₄_scalar * wdivₕ(Y.c.ρ * gradₕ(ᶜ∇²χ))
+        end
     end
     if turbconv_model isa PrognosticEDMFX
         (; ᶜ∇²q_totʲs) = p.hyperdiff

src/prognostic_equations/implicit/implicit_solver.jl

@@ -264,7 +264,6 @@ function ImplicitEquationJacobian(
                 (ρatke_if_available..., @name(c.uₕ)),
             )...,
         )
-
     end
 
     sgs_scalar_names = (
@@ -813,6 +812,7 @@ function update_implicit_equation_jacobian!(A, Y, p, dtγ, t)
                 dtγ * ᶜdiffusion_h_matrix ⋅ DiagonalMatrixRow(1 / ᶜρ)
         end
 
+
         MatrixFields.unrolled_foreach(tracer_info) do (ρq_name, q_name, _)
             MatrixFields.has_field(Y, ρq_name) || return
             ᶜq = MatrixFields.get_field(ᶜspecific, q_name)
@@ -823,8 +823,7 @@ function update_implicit_equation_jacobian!(A, Y, p, dtγ, t)
                 ᶜdiffusion_h_matrix_scaled,
                 ᶜdiffusion_h_matrix,
             )
-            @. ∂ᶜρq_err_∂ᶜρ =
-                dtγ * ᶜtridiagonal_matrix_scalar ⋅ DiagonalMatrixRow(-(ᶜq) / ᶜρ)
+            @. ∂ᶜρq_err_∂ᶜρ = zero(typeof(∂ᶜρq_err_∂ᶜρ))
             @. ∂ᶜρq_err_∂ᶜρq +=
                 dtγ * ᶜtridiagonal_matrix_scalar ⋅ DiagonalMatrixRow(1 / ᶜρ)
         end

src/prognostic_equations/surface_flux.jl

@@ -65,6 +65,8 @@ function surface_flux_tendency!(Yₜ, Y, p, t)
         end
         btt = boundary_tendency_scalar(ᶜχ, ρ_flux_χ)
         @. ᶜρχₜ -= btt
-        @. Yₜ.c.ρ -= btt
+        if χ_name == :q_tot
+            @. Yₜ.c.ρ -= btt
+        end
     end
 end

src/prognostic_equations/vertical_diffusion_boundary_layer.jl

@@ -54,6 +54,10 @@ function vertical_diffusion_boundary_layer_tendency!(
         @. ᶜρχₜ_diffusion =
             ᶜdivᵥ_ρχ(-(ᶠinterp(Y.c.ρ) * ᶠinterp(ᶜK_h_scaled) * ᶠgradᵥ(ᶜχ)))
         @. ᶜρχₜ -= ᶜρχₜ_diffusion
-        @. Yₜ.c.ρ -= ᶜρχₜ_diffusion
+        # Exclude contributions from diffusion of condensate, precipitation 
+        # in mass tendency
+        if χ_name == :q_tot
+            @. Yₜ.c.ρ -= ᶜρχₜ_diffusion
+        end
     end
 end