From b6c1d8b57114d4d1d1bffa0326f2422e35fa77fa Mon Sep 17 00:00:00 2001
From: Zhaoyi Shen <11598433+szy21@users.noreply.github.com>
Date: Tue, 1 Oct 2024 09:46:18 -0700
Subject: [PATCH] add a lower limit for pressure in radiation

---
 src/callbacks/callbacks.jl | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/callbacks/callbacks.jl b/src/callbacks/callbacks.jl
index f3be69cf03f..a5869a69a9a 100644
--- a/src/callbacks/callbacks.jl
+++ b/src/callbacks/callbacks.jl
@@ -89,7 +89,10 @@ NVTX.@annotate function rrtmgp_model_callback!(integrator)
 
     ᶜp = Fields.array2field(rrtmgp_model.center_pressure, axes(Y.c))
     ᶜT = Fields.array2field(rrtmgp_model.center_temperature, axes(Y.c))
-    @. ᶜp = TD.air_pressure(thermo_params, ᶜts)
+    # Here we multiply p_min by a small number to avoid exactly same
+    # pressure in the top layer and in the extra layer added in rrtmgp
+    p_min = RRTMGPI.get_p_min(rrtmgp_model)
+    @. ᶜp = max(TD.air_pressure(thermo_params, ᶜts), p_min * FT(1.01))
     # TODO: move this to RRTMGP
     @. ᶜT =
         min(max(TD.air_temperature(thermo_params, ᶜts), FT(T_min)), FT(T_max))