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pmf/ProcessLibrary/biomass_lue_co2_stockle.py

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+# -*- coding: utf-8 -*-
+"""
+Created on Tue Dec 16 15:27:21 2014
+
+@author: J. Kellner
+"""
+
+import math
+
+class Biomass_LUE_CO2_Stockle:
+    """
+    Calculates biomass growth with the radiation use efficiency concept.
+    
+    Calculates the daily biomass growth from a crop specific
+    radiation use efficiency (RUE) and the daily incoming absorbed
+    photosynthetic active radiation (aPAR). aPAR depends on the
+    plant leaf area index and a dimensionless extinction
+    coefficiant. RUE varies with change in the atmospheric CO2 concentration.
+    The underlying equation was published in Stöckle et al. (1992).
+    
+    Implementation
+    ==============
+    Biomass_LUE must be implemented with the crop specific parameters
+    for the LUE-concept.
+    
+    Call signature
+    ==============
+    Plant must be called with crop and environmental factors.
+    
+    """
+
+
+    def __init__(self,b_1,b_2):
+        """
+        Returns a Biomass_LUE instance.
+        
+        :type b_1: double
+        :param b_1: coefficient for RUE [-]   
+        :type b_2: double
+        :param b_2: coefficient for RUE [-]   
+        :rtype: biomass_lue
+        :return: Biomass_LUE instance
+        """
+        #Constant variables
+        self.b_1= b_1
+        self.b_2 = b_2
+
+
+        #State variables
+        self.total=0.
+        self.growthrate=0.
+        self.pot_total=0.
+        self.stress = 0.
+    @property
+    def PotentialGrowth(self):
+        """
+        Return potential growth without stress.
+        
+        :rtype: double
+        :return: Potential growth in [g biomass day-1].
+        """ 
+        return self.growthrate
+    @property
+    def ActualGrowth(self):
+        """
+        Return actual growth influenced by water and nitorgen stress.
+        
+        :rtype: double
+        :return: Actual growth in [g biomass day-1].
+        """ 
+        return self.growthrate * (1-self.stress)
+    @property
+    def Total(self):
+        """
+        Returns total biomass.
+        
+        :rtype: double
+        :return: Biomass in [g biomass day-1].
+        """ 
+        return self.total
+    def __call__(self,step,stress,Rs,interception,LAI,CO2_measured,senesced_leaf):  
+        """
+        Calculates the stressed and unstressed growth of the plant.
+        
+        :type step: double
+        :param step: Time step in [days].
+        :type Rs: double
+        :param Rs: total solar radiation [MJ m-2 day-1].
+        :type stress: double
+        :param stress: Parameter for water and nitrogen stress between 0 - 1. 
+        in [-].
+        :type LAI: double
+        :param LAI: Leaf area index of the plant in [m2 m-2].
+        :type CO2_measured: double
+        :param CO2_measured: atmospheric CO2 concentration in rings [ppm].
+        """
+
+        self.stress = stress
+        self.growthrate = self.PAR_a(Rs, interception)* self.rue_stockle(CO2_measured, self.b_1, self.b_2)   ################ N E W #############
+        self.total = self.total - senesced_leaf + self.growthrate * (1-self.stress) * step         
+        self.pot_total = self.pot_total + self.growthrate
+
+
+    def rue_stockle(self, C_measured, b_1, b_2):
+        """
+        Returns radiation use efficiency affected by CO2 concentration [g/MJ] according to Stockle et al. 1992
+        
+        This apporach is extracted from Stockle et al. 1992 to adapt the EPIC model to changing CO2 concentrations.
+        In this paper b1 = 7784 and b2 = 0.00107 to reach RUE = 3 at 350 ppm and RUE = 3.9 at 600 ppm.
+        
+        :type C_measured: double
+        :param C_measured: target CO2 concentration [µmol/mol]
+        :type b_1: double
+        :param b_1: parameter to adapt RUE for any value of CO2 concentration.
+        :type b_2: double
+        :param b_2: parameter to adapt RUE for any value of CO2 concentration.
+        """
+        return 100 * C_measured / (C_measured + b_1 *math.exp(- b_2 * C_measured))          
+
+
+    def PAR_a(self,Rs,interception):
+        """ 
+        Returns photosynthetically active absorbed radiation
+        
+        Canopy photosynthesis is closely related to the photosynthetically 
+        active (400 to 700 mm) absorbed radiation (PARa) by green tissue in the 
+        canopy. The values 0.5 is the fraction of total solar energy, which is 
+        photosynthetically active interception - fraction of total solar 
+        radiation flux, which is intercepted by the crop. The value 0.9 is the 
+        fraction of radiation absorbed by the crop  allowing for a 6 percent 
+        albedo and for inactive radiation absorption.
+        
+        :type Rs: double
+        :param Rs: total solar radiation [MJ m-2 day-1].
+        :type interception: double
+        :param interception: Fraction of total solar radiation flux, which is 
+        intercepted by the crop in [-].
+        
+        :rtype: double
+        :return: Photosynthetically active absorbed radiation in [MJ m-2 day-1].
+        """
+        return Rs*0.5*0.9*(1-interception)
+
+
+    def atmosphere_values(self,atmosphere,time_act):
+        """
+        Returns a method to interfere with the atmosphere interface over the 
+        plant instance.
+        
+        :type atmosphere: atmosphere
+        :param atmosphere: Atmosphere object from the plant interface soil.
+        :type time_act: datetime
+        :param time_act: Actual time in [DD,MM,JJJ].
+        :rtype: method
+        :return: Function for getting required atmosphere values.
+        """
+        return atmosphere.get_Rs(time_act)
+
+
+    def measured_CO2(self,atmosphere,time_act):
+        """
+        Returns a method to interfere with the atmosphere interface over the 
+        plant instance.
+        
+        :type atmosphere: atmosphere
+        :param atmosphere: Atmosphere object from the plant interface soil.
+        :type time_act: datetime
+        :param time_act: Actual time in [DD,MM,JJJ].
+        :rtype: method
+        :return: Function for getting elevated CO2 concentration
+        """
+        return atmosphere.get_CO2_measured(time_act)