From c61846ea1ccafff64becf5a5debba564dc0414aa Mon Sep 17 00:00:00 2001
From: XANTRONIX Industrial <xan@xantronix.com>
Date: Wed, 26 Feb 2025 20:33:56 -0500
Subject: [PATCH] Implement lapse() in thermo.py

---
 lib/xmet/thermo.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/xmet/thermo.py b/lib/xmet/thermo.py
index 4f76597..052e98f 100644
--- a/lib/xmet/thermo.py
+++ b/lib/xmet/thermo.py
@@ -1,3 +1,6 @@
+LAPSE_RATE_MOIST = 4.0 # degrees C per km
+LAPSE_RATE_DRY   = 9.8
+
 def vapor_pressure(dewpoint: float) -> float:
     return 6.11 * 10 * (
         (7.5 * dewpoint) / (237.3 * dewpoint)
@@ -20,3 +23,6 @@ def saturated_mixing_ratio(temp: float, pressure: float) -> float:
 
 def lcl(temp: float, dewpoint: float) -> float:
     return (temp - dewpoint) / 0.008
+
+def lapse(temp: float, rate: float, delta: float) -> float:
+    return temp - (rate * (delta / 1000))