class Hargreaves(Model):
def initial(self):
self.temperature_module = Temperature(self)
self.extraterrestrial_radiation_module = ExtraterrestrialRadiation(
self)
self.temperature_module.initial()
self.extraterrestrial_radiation_module.initial()
self.ETref = np.zeros((self.domain.nxy))
self.reporting_module = Reporting(self,
variable_list,
config_section='ETREF')
self.reporting_module.initial()
def hargreaves(self):
self.ETref = (
0.0023 *
(self.extraterrestrial_radiation * 0.408) # MJ m-2 d-1 -> mm d-1
* ((np.maximum(0, (self.tmean.values[0, self.domain.mask.values] -
273.0))) + 17.8) *
np.sqrt(
np.maximum(0, (self.tmax.values[0, self.domain.mask.values] -
self.tmin.values[0, self.domain.mask.values]))))
def dynamic(self):
self.temperature_module.dynamic()
self.extraterrestrial_radiation_module.dynamic()
self.hargreaves()
self.reporting_module.dynamic()
def initial(self):
self.temperature_module = Temperature(self)
self.extraterrestrial_radiation_module = ExtraterrestrialRadiation(
self)
self.temperature_module.initial()
self.extraterrestrial_radiation_module.initial()
self.ETref = np.zeros((self.domain.nxy))
self.reporting_module = Reporting(
self, variable_list, config_section='ETREF')
self.reporting_module.initial()
def initial(self):
# self.longwave_radiation_module.initial()
self.shortwave_radiation_module.initial()
self.extraterrestrial_radiation_module.initial()
self.relative_humidity_module.initial()
self.specific_humidity_module.initial()
self.surface_pressure_module.initial()
self.vapour_pressure_module.initial()
self.net_radiation_module.initial()
self.temperature_module.initial()
self.wind_module.initial()
self.reporting_module = Reporting(self, variable_list)
self.reporting_module.initial()
class PenmanMonteith(Model):
def __init__(self, config, time, domain, init=None):
super(PenmanMonteith, self).__init__(config,
time,
domain,
is_1d=True,
init=init)
self.temperature_module = Temperature(self)
# self.longwave_radiation_module = LongwaveRadiation(self)
self.shortwave_radiation_module = ShortwaveRadiation(self)
self.extraterrestrial_radiation_module = ExtraterrestrialRadiation(
self)
self.relative_humidity_module = RelativeHumidity(self)
self.specific_humidity_module = SpecificHumidity(self)
self.surface_pressure_module = SurfacePressure(self)
self.vapour_pressure_module = VapourPressure(self)
self.net_radiation_module = NetRadiation(self)
self.wind_module = Wind(self)
self.ETref = np.zeros((self.domain.nxy))
def initial(self):
# self.longwave_radiation_module.initial()
self.shortwave_radiation_module.initial()
self.extraterrestrial_radiation_module.initial()
self.relative_humidity_module.initial()
self.specific_humidity_module.initial()
self.surface_pressure_module.initial()
self.vapour_pressure_module.initial()
self.net_radiation_module.initial()
self.temperature_module.initial()
self.wind_module.initial()
self.reporting_module = Reporting(self, variable_list)
self.reporting_module.initial()
def penman_monteith(self):
"""Function implementing the Penman-Monteith
equation (*NOT* FAO version)
"""
cp = 0.001013 # specific heat of air 1013 [MJ kg-1 K-1]
TimeStepSecs = 86400 # timestep in seconds
rs = 70 # surface resistance, 70 [s m-1]
R = 287.058 # Universal gas constant [J kg-1 K-1]
# ratio of water vapour/dry air molecular weights [-]
eps = 0.622
# g = 9.81 # gravitational constant [m s-2]
rho = self.surface_pressure.values / \
(self.tmean.values * R) # density of air [kg m-3]
# latent heat [MJ kg-1]
latent_heat = (2.501 - (0.002361 * (self.tmean.values - 273.15)))
# slope of vapour pressure [kPa K-1]
deltop = 4098. * \
(0.6108 * np.exp((17.27 * (self.tmean.values - 273.15)) /
((self.tmean.values - 273.15) + 237.3)))
delbase = ((self.tmean.values - 273.15) + 237.3)**2
delta = deltop / delbase
# psychrometric constant [kPa K-1]
gamma = cp * (self.surface_pressure.values / 1000) / \
(eps * latent_heat)
# aerodynamic resistance [m s-1]
z = 10 # height of wind speed variable (10 meters above surface)
Wsp_2 = self.wind.values * 4.87 / (np.log(67.8 * z - 5.42))
ra = np.divide(208., Wsp_2, out=np.zeros_like(Wsp_2), where=Wsp_2 != 0)
# Penman-Monteith equation (NB unit conversion)
PETtop = np.maximum(
((delta * 1e3) * self.net_radiation + rho *
(cp * 1e6) * np.divide(self.vapour_pressure_deficit,
ra,
out=np.zeros_like(ra),
where=ra != 0)), 1)
PETbase = np.maximum(
((delta * 1e3) + (gamma * 1e3) *
(1 + np.divide(rs, ra, out=np.zeros_like(ra), where=ra != 0))), 1)
PET = np.maximum(PETtop / PETbase, 0)
PETmm = np.maximum((PET / (latent_heat * 1e6) * TimeStepSecs), 0)
self.ETref = PETmm.copy()
# FAO Penman-Monteith:
# PETtop = (
# (0.408 * delta * self.net_radiation * 0.086400)
# + (gamma
# * (900 / self.tmean)
# * Wsp_2
# * self.vapour_pressure_deficit / 1e3)
# )
# PETbot = (delta + gamma * (1 + 0.34 * Wsp_2))
# PETmm = PETtop / PETbot
# self.ETref = PETmm.copy()
def dynamic(self):
# logger.info("Reading forcings for time %s", self._modelTime)
self.temperature_module.dynamic()
# self.longwave_radiation_module.dynamic()
self.shortwave_radiation_module.dynamic()
self.extraterrestrial_radiation_module.dynamic()
self.relative_humidity_module.dynamic()
self.specific_humidity_module.dynamic()
self.surface_pressure_module.dynamic()
self.vapour_pressure_module.dynamic()
self.net_radiation_module.dynamic()
self.wind_module.dynamic()
self.penman_monteith()
self.reporting_module.dynamic()