"""Some simple tools for configuring the model."""
from firedrake import Function, FunctionSpace, Constant
import inspect
__all__ = [
"BoussinesqParameters", "CompressibleParameters",
"ShallowWaterParameters",
"SpongeLayerParameters", "DiffusionParameters", "BoundaryLayerParameters",
]
class EquationParameters(object):
"""A base configuration object for storing equation parameters."""
mesh = None
def __init__(self, mesh, **kwargs):
"""
Args:
mesh: for creating the real function space
**kwargs: attributes and their values to be stored in the object.
"""
self.mesh = mesh
typecheck = lambda val: type(val) in [float, int, Constant]
params = dict(inspect.getmembers(self, typecheck))
params.update(kwargs.items())
for name, value in params.items():
self.__setattr__(name, value)
def __setattr__(self, name, value):
"""
Sets the model configuration attributes.
When attributes are provided as floats or integers, these are converted
to Firedrake :class:`Constant` objects, other than a handful of special
integers.
Args:
name: the attribute's name.
value: the value to provide to the attribute.
Raises:
AttributeError: if the :class:`Configuration` object does not have
this attribute pre-defined.
"""
if not hasattr(self, name):
raise AttributeError("'%s' object has no attribute '%s'" % (type(self).__name__, name))
# Almost all parameters should be functions on the real space
# -- but there are some specific exceptions which should be
# kept as integers
if self.mesh is not None:
# This check is required so that on instantiation we do
# not hit this line while self.mesh is still None
R = FunctionSpace(self.mesh, 'R', 0)
if type(value) in [float, int, Constant]:
object.__setattr__(self, name, Function(R, val=float(value)))
else:
object.__setattr__(self, name, value)
[docs]
class BoussinesqParameters(EquationParameters):
"""Physical parameters for the Boussinesq equations."""
g = 9.810616
N = 0.01 # Brunt-Vaisala frequency (1/s)
cs = 340 # sound speed (for compressible case) (m/s)
Omega = None
[docs]
class CompressibleParameters(EquationParameters):
"""Physical parameters for the Compressible Euler equations."""
g = 9.810616
N = 0.01 # Brunt-Vaisala frequency (1/s)
cp = 1004.5 # SHC of dry air at const. pressure (J/kg/K)
R_d = 287. # Gas constant for dry air (J/kg/K)
kappa = 2.0/7.0 # R_d/c_p
p_0 = 1000.0*100.0 # reference pressure (Pa, not hPa)
cv = 717.5 # SHC of dry air at const. volume (J/kg/K)
c_pl = 4186. # SHC of liq. wat. at const. pressure (J/kg/K)
c_pv = 1885. # SHC of wat. vap. at const. pressure (J/kg/K)
c_vv = 1424. # SHC of wat. vap. at const. pressure (J/kg/K)
R_v = 461. # gas constant of water vapour
L_v0 = 2.5e6 # ref. value for latent heat of vap. (J/kg)
T_0 = 273.15 # ref. temperature
w_sat1 = 380.3 # first const. in Teten's formula (Pa)
w_sat2 = -17.27 # second const. in Teten's formula (no units)
w_sat3 = 35.86 # third const. in Teten's formula (K)
w_sat4 = 610.9 # fourth const. in Teten's formula (Pa)
Omega = None # Rotation rate
[docs]
class ShallowWaterParameters(EquationParameters):
"""Physical parameters for the shallow-water equations."""
g = 9.80616
Omega = 7.292e-5 # rotation rate
H = None # mean depth
# Factor that multiplies the vapour in the equivalent buoyancy
# formulation of the thermal shallow water equations
beta2 = None
# Scaling factor for the saturation function in the equivalent buoyancy
# formulation of the thermal shallow water equations
nu = None
# Scaling factor for the saturation function in the equivalent buoyancy
# formulation of the thermal shallow water equations
q0 = None
[docs]
class SpongeLayerParameters(EquationParameters):
"""Specifies parameters describing a 'sponge' (damping) layer."""
H = None
z_level = None
mubar = None
[docs]
class DiffusionParameters(EquationParameters):
"""Parameters for a diffusion term with an interior penalty method."""
kappa = None
mu = None
[docs]
class BoundaryLayerParameters(EquationParameters):
"""
Parameters for the idealised wind drag, surface flux and boundary layer
mixing schemes.
"""
coeff_drag_0 = 7e-4 # Zeroth drag coefficient (dimensionless)
coeff_drag_1 = 6.5e-5 # First drag coefficient (s/m)
coeff_drag_2 = 2e-3 # Second drag coefficient (dimensionless)
coeff_heat = 1.1e-3 # Dimensionless surface sensible heat coefficient
coeff_evap = 1.1e-3 # Dimensionless surface evaporation coefficient
height_surface_layer = 75. # Height (m) of surface level (usually lowest level)
mu = 100. # Interior penalty coefficient for vertical diffusion
class HeldSuarezParameters(EquationParameters):
"""
Parameters used in the default configuration for the Held Suarez test case.
"""
T0stra = 200 # Stratosphere temp
T0surf = 315 # Surface temperature at equator
T0horiz = 60 # Equator to pole temperature difference
T0vert = 10 # Stability parameter
sigmab = 0.7 # Height of the boundary layer
tau_d = 40 * 24 * 60 * 60 # 40 day time scale
tau_u = 4 * 24 * 60 * 60 # 4 day timescale