From 66bc9aec47fdf71d020f863d0888f97c6347e346 Mon Sep 17 00:00:00 2001
From: Anna Jaruga <ajaruga@caltech.edu>
Date: Fri, 5 Jul 2024 16:30:50 -0700
Subject: [PATCH] Add prescribed cloud droplet number concentration for rain
 autoconversion

---
 .../microphysics/microphysics_wrappers.jl                  | 7 +++++--
 src/parameters/create_parameters.jl                        | 6 ++++++
 toml/single_column_precipitation_test.toml                 | 3 +++
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/parameterized_tendencies/microphysics/microphysics_wrappers.jl b/src/parameterized_tendencies/microphysics/microphysics_wrappers.jl
index 9c8a7642d0..5379909bc2 100644
--- a/src/parameterized_tendencies/microphysics/microphysics_wrappers.jl
+++ b/src/parameterized_tendencies/microphysics/microphysics_wrappers.jl
@@ -3,6 +3,7 @@
 import Thermodynamics as TD
 import CloudMicrophysics.Microphysics0M as CM0
 import CloudMicrophysics.Microphysics1M as CM1
+import CloudMicrophysics.Microphysics2M as CM2
 import CloudMicrophysics.MicrophysicsNonEq as CMNe
 import CloudMicrophysics.Parameters as CMP
 
@@ -172,10 +173,12 @@ function compute_precipitation_sources!(
 
     #! format: off
     # rain autoconversion: q_liq -> q_rain
-    @. Sᵖ = min(
-        limit(qₗ(thp, ts), dt, 5),
+    @. Sᵖ = ifelse(
+        mp.Ndp <= 0,
         CM1.conv_q_liq_to_q_rai(mp.pr.acnv1M, qₗ(thp, ts), true),
+        CM2.conv_q_liq_to_q_rai(mp.var, qₗ(thp, ts), ρ, mp.Ndp),
     )
+    @. Sᵖ = min(limit(qₗ(thp, ts), dt, 5), Sᵖ)
     @. Sqₜᵖ -= Sᵖ
     @. Sqᵣᵖ += Sᵖ
     @. Seₜᵖ -= Sᵖ * (Iₗ(thp, ts) + Φ)
diff --git a/src/parameters/create_parameters.jl b/src/parameters/create_parameters.jl
index 2136717261..61dab684d5 100644
--- a/src/parameters/create_parameters.jl
+++ b/src/parameters/create_parameters.jl
@@ -96,6 +96,12 @@ function create_parameter_set(config::AtmosConfig)
                 ce = CM.Parameters.CollisionEff(toml_dict),
                 tv = CM.Parameters.Blk1MVelType(toml_dict),
                 aps = CM.Parameters.AirProperties(toml_dict),
+                var = CM.Parameters.VarTimescaleAcnv(toml_dict),
+                Ndp = CP.get_parameter_values(
+                    toml_dict,
+                    "prescribed_cloud_droplet_number_concentration",
+                    "ClimaAtmos",
+                ).prescribed_cloud_droplet_number_concentration,
             )
         else
             error("Invalid precip_model $(precip_model)")
diff --git a/toml/single_column_precipitation_test.toml b/toml/single_column_precipitation_test.toml
index 6d7a943ddb..7012136c83 100644
--- a/toml/single_column_precipitation_test.toml
+++ b/toml/single_column_precipitation_test.toml
@@ -1,2 +1,5 @@
 [C_H]
 value = 0.0
+
+[prescribed_cloud_droplet_number_concentration]
+value = 0.0