private double soilwat2_eeq_fac(MetData Met)
{
//*+ Mission Statement
//* Calculate the Equilibrium Evaporation Rate
if (Met.maxt > cons.max_crit_temp)
{
//! at very high max temps eo/eeq increases
//! beyond its normal value of 1.1
return((Met.maxt - cons.max_crit_temp) * 0.05 + 1.1);
}
else
{
if (Met.maxt < cons.min_crit_temp)
{
//! at very low max temperatures eo/eeq
//! decreases below its normal value of 1.1
//! note that there is a discontinuity at tmax = 5
//! it would be better at tmax = 6.1, or change the
//! .18 to .188 or change the 20 to 21.1
return(0.01 * Math.Exp(0.18 * (Met.maxt + 20.0)));
}
}
return(1.1); //sv- normal value of eeq fac (eo/eeq)
}
public void CalcEo_AtmosphericPotential(MetData Met, CanopyData Canopy)
{
//Get Eo and assign it to the public Eo field for this object.
//private void soilwat2_priestly_taylor()
// {
double albedo; //! albedo taking into account plant material
double eeq; //! equilibrium evaporation rate (mm)
double wt_ave_temp; //! weighted mean temperature for the day (oC)
//* ******* calculate potential evaporation from soil surface (eos) ******
// ! find equilibrium evap rate as a
// ! function of radiation, albedo, and temp.
albedo = cons.max_albedo - (cons.max_albedo - salb) * (1.0 - Canopy.cover_green_sum);
// ! wt_ave_temp is mean temp, weighted towards max.
wt_ave_temp = (0.60 * Met.maxt) + (0.40 * Met.mint);
eeq = Met.radn * 23.8846 * (0.000204 - 0.000183 * albedo) * (wt_ave_temp + 29.0);
//! find potential evapotranspiration (eo) from equilibrium evap rate
Eo = eeq * soilwat2_eeq_fac(Met);
// }
}
private void OnSimulationCommencing(object sender, EventArgs e)
{
SaveModuleConstants();
//daily inputs
met = new MetData();
irrig = new IrrigData();
canopy = new CanopyData();
surfaceCover = new SurfaceCoverData();
//optional daily inputs
runon = 0.0;
interception = 0.0;
residueinterception = 0.0;
if (Soil.Thickness != null)
{
try
{
SoilObject = new SoilWaterSoil(constants, Soil); //constructor can throw an Exception
surfaceFactory = new SurfaceFactory();
surface = surfaceFactory.GetSurface(SoilObject, Clock); //constructor can throw an Exception (Evap class constructor too)
//optional inputs (array)
inflow_lat = null;
}
catch (Exception Ex)
{
throw new ApsimXException(this, Ex.Message); //catch any constructor Exceptions and rethrow as an ApsimXException.
}
}
else
{
throw new ApsimXException(this, "SoilWater module has detected that the Soil has no layers.");
}
}
private double soilwat2_eeq_fac(MetData Met)
{
//*+ Mission Statement
//* Calculate the Equilibrium Evaporation Rate
if (Met.maxt > cons.max_crit_temp)
{
//! at very high max temps eo/eeq increases
//! beyond its normal value of 1.1
return ((Met.maxt - cons.max_crit_temp) * 0.05 + 1.1);
}
else
{
if (Met.maxt < cons.min_crit_temp)
{
//! at very low max temperatures eo/eeq
//! decreases below its normal value of 1.1
//! note that there is a discontinuity at tmax = 5
//! it would be better at tmax = 6.1, or change the
//! .18 to .188 or change the 20 to 21.1
return (0.01 * Math.Exp(0.18 * (Met.maxt + 20.0)));
}
}
return 1.1; //sv- normal value of eeq fac (eo/eeq)
}
public void CalcEo_AtmosphericPotential(MetData Met, CanopyData Canopy)
{
//Get Eo and assign it to the public Eo field for this object.
//private void soilwat2_priestly_taylor()
// {
double albedo; //! albedo taking into account plant material
double eeq; //! equilibrium evaporation rate (mm)
double wt_ave_temp; //! weighted mean temperature for the day (oC)
//* ******* calculate potential evaporation from soil surface (eos) ******
// ! find equilibrium evap rate as a
// ! function of radiation, albedo, and temp.
albedo = cons.max_albedo - (cons.max_albedo - salb) * (1.0 - Canopy.cover_green_sum);
// ! wt_ave_temp is mean temp, weighted towards max.
wt_ave_temp = (0.60 * Met.maxt) + (0.40 * Met.mint);
eeq = Met.radn * 23.8846 * (0.000204 - 0.000183 * albedo) * (wt_ave_temp + 29.0);
//! find potential evapotranspiration (eo) from equilibrium evap rate
Eo = eeq * soilwat2_eeq_fac(Met);
// }
}
