From 1a6cd17363d8d13202ffdebceb7256c7586d1776 Mon Sep 17 00:00:00 2001
From: Ove <ovehaugv@outlook.com>
Date: Wed, 29 Nov 2023 15:19:00 +0100
Subject: [PATCH] fix floating point error in activation when T<-50C

---
 src/chemistry/oslo_aero/NdParam.f | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/chemistry/oslo_aero/NdParam.f b/src/chemistry/oslo_aero/NdParam.f
index 417a640a15..44cfe2a46a 100644
--- a/src/chemistry/oslo_aero/NdParam.f
+++ b/src/chemistry/oslo_aero/NdParam.f
@@ -235,6 +235,15 @@ SUBROUTINE PDFACTIV (WPARC,TP,AKK,A,B,ACCOM,SG,SIGW,
       DOUBLE PRECISION NACTI, DENOM
       REAL             PDF
 
+      !C Check if temperature is below -50C
+      IF (TPARC.LT.223.0) THEN
+            SMAX  = 0d0
+            NACT  = 0d0
+            ACF = 0d0
+            MACF = 0d0
+            RETURN
+      ENDIF
+
 !C
 !C *** Single updraft case
 !C