From 3585011c55c615146ce6c6debc064c72924c7b9f Mon Sep 17 00:00:00 2001
From: Marcus Gastaldello
 <116652649+MarcusGastaldello@users.noreply.github.com>
Date: Thu, 25 Jan 2024 14:50:30 +0100
Subject: [PATCH 1/3] Update constants.py

Added option for new Yen et al. (1981) specific heat capacity method
---
 constants.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/constants.py b/constants.py
index 45340ec7..2e118946 100644
--- a/constants.py
+++ b/constants.py
@@ -17,6 +17,7 @@
 roughness_method = 'Moelg12'                    # possibilities: 'Moelg12'
 saturation_water_vapour_method = 'Sonntag90'    # possibilities: 'Sonntag90'
 thermal_conductivity_method = 'bulk'		    # possibilities: 'bulk', 'empirical'
+specific_heat_capacity_method = 'bulk'          # possibilities: 'bulk', 'Yen81'
 sfc_temperature_method = 'SLSQP'                # possibilities: 'L-BFGS-B', 'SLSQP'(faster), 'Newton' (Secant, fastest)'
 
 # WRF_X_CSPY: for efficiency and consistency

From ffd21b7cfacfabf3e6308c3a6b7c30706b30f774 Mon Sep 17 00:00:00 2001
From: Marcus Gastaldello
 <116652649+MarcusGastaldello@users.noreply.github.com>
Date: Thu, 25 Jan 2024 15:22:12 +0100
Subject: [PATCH 2/3] Update node.py

Yen (1981) specific heat method added.
---
 cosipy/cpkernel/node.py | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/cosipy/cpkernel/node.py b/cosipy/cpkernel/node.py
index 88a6abce..21059fa8 100644
--- a/cosipy/cpkernel/node.py
+++ b/cosipy/cpkernel/node.py
@@ -131,7 +131,15 @@ def get_layer_specific_heat(self):
             cp : float
                 Specific heat [:math:`J~kg^{-1}~K^{-1}`]
         """
-        return self.get_layer_ice_fraction()*spec_heat_ice + self.get_layer_air_porosity()*spec_heat_air + self.get_layer_liquid_water_content()*spec_heat_water
+
+        methods_allowed = ['bulk','Yen81']
+        if specific_heat_capacity_method == 'bulk':    
+            cp = self.get_layer_ice_fraction() * spec_heat_ice + self.get_layer_air_porosity() * spec_heat_air + self.get_layer_liquid_water_content() * spec_heat_water
+        elif specific_heat_capacity_method == 'Yen81':
+            cp = 152.2 + 7.122 * self.get_layer_temperature()
+        else:
+            raise ValueError("Specific heat method = \"{:s}\" is not allowed, must be one of {:s}".format(specific_heat_capacity_method, ", ".join(methods_allowed)))
+        return cp
 
     def get_layer_liquid_water_content(self):
         """ Returns the liquid water content of the node.

From 15bb7076ad5bc5d87e3c175b2baac6ba0e5f1c88 Mon Sep 17 00:00:00 2001
From: Marcus Gastaldello
 <116652649+MarcusGastaldello@users.noreply.github.com>
Date: Thu, 25 Jan 2024 15:24:28 +0100
Subject: [PATCH 3/3] Update node.py

---
 cosipy/cpkernel/node.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cosipy/cpkernel/node.py b/cosipy/cpkernel/node.py
index 21059fa8..3bf8576c 100644
--- a/cosipy/cpkernel/node.py
+++ b/cosipy/cpkernel/node.py
@@ -135,7 +135,7 @@ def get_layer_specific_heat(self):
         methods_allowed = ['bulk','Yen81']
         if specific_heat_capacity_method == 'bulk':    
             cp = self.get_layer_ice_fraction() * spec_heat_ice + self.get_layer_air_porosity() * spec_heat_air + self.get_layer_liquid_water_content() * spec_heat_water
-        elif specific_heat_capacity_method == 'Yen81':
+        elif specific_heat_capacity_method == 'Yen81':    # empirical parameterisation according to Yen, 1981
             cp = 152.2 + 7.122 * self.get_layer_temperature()
         else:
             raise ValueError("Specific heat method = \"{:s}\" is not allowed, must be one of {:s}".format(specific_heat_capacity_method, ", ".join(methods_allowed)))