"""Object-oriented code for radiative-convective models with grey-gas radiation.
Code developed by Brian Rose, University at Albany
brose@albany.edu
Note that the column models by default represent global, time averages.
Thus the insolation is a prescribed constant.
Here is an example to implement seasonal insolation at 45 degrees North
:Example:
.. code-block:: python
import climlab
# create the column model object
col = climlab.GreyRadiationModel()
# create a new latitude axis with a single point
lat = climlab.domain.Axis(axis_type='lat', points=45.)
# add this new axis to the surface domain
col.Ts.domain.axes['lat'] = lat
# create a new insolation process using this domain
Q = climlab.radiation.insolation.DailyInsolation(domains=col.Ts.domain, **col.param)
# replace the fixed insolation subprocess in the column model
col.add_subprocess('insolation', Q)
This model is now a single column with seasonally varying insolation
calculated for 45N.
"""
from __future__ import division
import numpy as np
from climlab import constants as const
from climlab.process.time_dependent_process import TimeDependentProcess
from climlab.domain.initial import column_state
from climlab.domain.field import Field
from climlab.radiation.insolation import FixedInsolation
from climlab.radiation.greygas import GreyGas, GreyGasSW
from climlab.convection.convadj import ConvectiveAdjustment
from climlab.radiation.nband import ThreeBandSW, FourBandLW, FourBandSW
from climlab.radiation.water_vapor import ManabeWaterVapor
[docs]
class GreyRadiationModel(TimeDependentProcess):
def __init__(self,
num_lev=30,
num_lat=1,
lev=None,
lat=None,
water_depth=1.0,
albedo_sfc=0.299,
timestep=1. * const.seconds_per_day,
Q=341.3,
# absorption coefficient in m**2 / kg
abs_coeff=1.229E-4,
**kwargs):
# Check to see if an initial state is already provided
# If not, make one
if 'state' not in kwargs:
state = column_state(num_lev, num_lat, lev, lat, water_depth)
kwargs.update({'state': state})
super(GreyRadiationModel, self).__init__(timestep=timestep, **kwargs)
self.param['water_depth'] = water_depth
self.param['albedo_sfc'] = albedo_sfc
self.param['Q'] = Q
self.param['abs_coeff'] = abs_coeff
sfc = self.Ts.domain
atm = self.Tatm.domain
# create sub-models for longwave and shortwave radiation
dp = self.Tatm.domain.lev.delta
absorbLW = compute_layer_absorptivity(self.param['abs_coeff'], dp)
absorbLW = Field(np.tile(absorbLW, sfc.shape), domain=atm)
absorbSW = np.zeros_like(absorbLW)
longwave = GreyGas(state=self.state, absorptivity=absorbLW,
albedo_sfc=0)
shortwave = GreyGasSW(state=self.state, absorptivity=absorbSW,
albedo_sfc=self.param['albedo_sfc'])
# sub-model for insolation ... here we just set constant Q
thisQ = self.param['Q']*np.ones_like(self.Ts)
Q = FixedInsolation(S0=thisQ, domains=sfc, **self.param)
self.add_subprocess('LW', longwave)
self.add_subprocess('SW', shortwave)
self.add_subprocess('insolation', Q)
newdiags = ['OLR',
'LW_down_sfc',
'LW_up_sfc',
'LW_absorbed_sfc',
'LW_absorbed_atm',
'LW_emission',
'ASR',
'SW_absorbed_sfc',
'SW_absorbed_atm',
'SW_up_sfc',
'SW_up_TOA',
'SW_down_TOA',
'planetary_albedo']
for name in newdiags:
self.add_diagnostic(name)
# This process has to handle the coupling between
# insolation and column radiation
self.subprocess['SW'].flux_from_space = \
self.subprocess['insolation'].diagnostics['insolation']
def _compute(self):
# set diagnostics
self.do_diagnostics()
# no tendencies for the parent process
tendencies = {}
for name, var in self.state.items():
tendencies[name] = var * 0.
return tendencies
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def do_diagnostics(self):
'''Set all the diagnostics from long and shortwave radiation.'''
self.OLR = self.subprocess['LW'].flux_to_space
self.LW_down_sfc = self.subprocess['LW'].flux_to_sfc
self.LW_up_sfc = self.subprocess['LW'].flux_from_sfc
self.LW_absorbed_sfc = self.LW_down_sfc - self.LW_up_sfc
self.LW_absorbed_atm = self.subprocess['LW'].absorbed
self.LW_emission = self.subprocess['LW'].emission
# contributions to OLR from surface and atm. levels
#self.diagnostics['OLR_sfc'] = self.flux['sfc2space']
#self.diagnostics['OLR_atm'] = self.flux['atm2space']
self.ASR = (self.subprocess['SW'].flux_from_space -
self.subprocess['SW'].flux_to_space)
#self.SW_absorbed_sfc = (self.subprocess['surface'].SW_from_atm -
# self.subprocess['surface'].SW_to_atm)
self.SW_absorbed_atm = self.subprocess['SW'].absorbed
self.SW_down_sfc = self.subprocess['SW'].flux_to_sfc
self.SW_up_sfc = self.subprocess['SW'].flux_from_sfc
self.SW_absorbed_sfc = self.SW_down_sfc - self.SW_up_sfc
self.SW_up_TOA = self.subprocess['SW'].flux_to_space
self.SW_down_TOA = self.subprocess['SW'].flux_from_space
self.planetary_albedo = (self.subprocess['SW'].flux_to_space /
self.subprocess['SW'].flux_from_space)
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class RadiativeConvectiveModel(GreyRadiationModel):
def __init__(self,
# lapse rate for convective adjustment, in K / km
adj_lapse_rate=6.5,
**kwargs):
super(RadiativeConvectiveModel, self).__init__(**kwargs)
self.param['adj_lapse_rate'] = adj_lapse_rate
self.add_subprocess('convective adjustment', \
ConvectiveAdjustment(state=self.state, **self.param))
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class BandRCModel(RadiativeConvectiveModel):
def __init__(self, **kwargs):
super(BandRCModel, self).__init__(**kwargs)
# Initialize specific humidity
h2o = ManabeWaterVapor(state=self.state, **self.param)
self.add_subprocess('H2O', h2o)
# q is an input field for this process, which is set by subproc
# (though in this sense it is actually diagnostic...)
newinput = ['q']
self.add_input('q')
self.q = self.subprocess['H2O'].q
# initialize radiatively active gas inventories
self.absorber_vmr = {}
self.absorber_vmr['CO2'] = 380.E-6 * np.ones_like(self.Tatm)
self.absorber_vmr['O3'] = np.zeros_like(self.Tatm)
# water vapor is actually specific humidity, not VMR.
self.absorber_vmr['H2O'] = self.q
longwave = FourBandLW(state=self.state,
absorber_vmr=self.absorber_vmr,
albedo_sfc=0.)
shortwave = ThreeBandSW(state=self.state,
absorber_vmr=self.absorber_vmr,
emissivity_sfc=0.,
albedo_sfc=self.param['albedo_sfc'])
self.add_subprocess('LW', longwave)
self.add_subprocess('SW', shortwave)
# This process has to handle the coupling between
# insolation and column radiation
self.subprocess['SW'].flux_from_space = \
self.subprocess['insolation'].diagnostics['insolation']
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def compute_layer_absorptivity(abs_coeff, dp):
'''Compute layer absorptivity from a constant absorption coefficient.'''
return (2. / (1 + 2. * const.g / abs_coeff /
(dp * const.mb_to_Pa)))
