def qair2rh(qair, temp, press=1013.25):
"""
Specific humidity to relative humidity
qair: DimArray or NDArray or number
Specific humidity - dimensionless (e.g. kg/kg) ratio of water mass / total air mass
temp: DimArray or NDArray or number
Temperature - degree c
press: DimArray or NDArray or number
Pressure - hPa (mb)
return: DimArray or NDArray or number
Relative humidity - %
"""
if isinstance(press, NDArray) or isinstance(press, DimArray):
p = press.asarray()
else:
p = press
if isinstance(qair, NDArray):
r = NDArray(MeteoMath.qair2rh(qair.asarray(), temp.asarray(), p))
if isinstance(qair, DimArray):
r = DimArray(r, qair.dims, qair.fill_value, qair.proj)
return r
else:
return MeteoMath.qair2rh(qair, temp, press)
def p2h(press):
"""
Pressure to height
:param press: (*float*) Pressure - hPa.
:returns: (*float*) Height - meter.
"""
if isinstance(press, NDArray):
r = NDArray(MeteoMath.press2Height(press.asarray()))
if isinstance(press, DimArray):
r = DimArray(r, press.dims, press.fill_value, press.proj)
return r
else:
return MeteoMath.press2Height(press)
def h2p(height):
"""
Height to pressure
:param height: (*float*) Height - meter.
:returns: (*float*) Pressure - hPa.
"""
if isinstance(height, NDArray):
r = NDArray(MeteoMath.height2Press(height.asarray()))
if isinstance(height, DimArray):
r = DimArray(r, height.dims, height.fill_value, height.proj)
return r
else:
return MeteoMath.height2Press(height)
def get_slp(wrfin, timeidx=0, units='hPa'):
'''
Return the sea level pressure in the specified units.
This function extracts the necessary variables from the NetCDF file
object in order to perform the calculation.
:param wrfin: (*DimDataFile*) Data file.
:param timeidx: (*int*) Time index.
:param units: (*string*) The desired units.
:returns: (*array*) Sea level pressure.
'''
t = wrfin['T'][timeidx, :, :, :]
p = wrfin['P'][timeidx, :, :, :]
pb = wrfin['PB'][timeidx, :, :, :]
qvapor = wrfin['QVAPOR'][timeidx, :, :, :]
ph = wrfin['PH'][timeidx, :, :, :]
phb = wrfin['PHB'][timeidx, :, :, :]
full_t = t + constants.T_BASE
full_p = p + pb
qvapor[qvapor < 0] = 0.
full_ph = (ph + phb) / constants.g
destag_ph = destagger(full_ph, -3)
tk = meteo.temperature_from_potential_temperature(full_p * 0.01, full_t)
slp = MeteoMath.calSeaPrs(destag_ph._array, tk._array, full_p._array,
qvapor._array)
return DimArray(slp, dims=t.dims[1:])
def vorticity(u, v, x=None, y=None):
"""
Calculates the vertical component of the curl (ie, vorticity). The data should be lon/lat projection.
:param u: (*array*) U component array (2D).
:param v: (*array*) V component array (2D).
:param x: (*array*) X coordinate array (1D).
:param y: (*array*) Y coordinate array (1D).
:returns: Array of the vertical component of the curl.
"""
if x is None or y is None:
if isinstance(u, DimArray) and isinstance(v, DimArray):
x = u.dimvalue(1)
y = u.dimvalue(0)
else:
raise ValueError("Need x, y coordinates")
if isinstance(x, (list, tuple)):
x = np.array(x)
if isinstance(y, (list, tuple)):
y = np.array(y)
r = MeteoMath.hcurl(u.asarray(), v.asarray(), x.asarray(), y.asarray())
return DimArray(NDArray(r), u.dims, u.fill_value, u.proj)
def divergence(u, v, x=None, y=None):
'''
Calculates the horizontal divergence using finite differencing. The data should be lon/lat projection.
:param u: (*array*) U component array.
:param v: (*array*) V component array.
:param x: (*array*) X coordinate.
:param y: (*array*) Y coordinate.
:returns: Array of the horizontal divergence.
'''
ny = u.shape[-2]
nx = u.shape[-1]
if x is None:
if isinstance(u, DimArray):
x = u.dimvalue(-1)
else:
x = np.arange(nx)
elif isinstance(x, (list, tuple)):
x = np.array(x)
if y is None:
if isinstance(v, DimArray):
y = u.dimvalue(-2)
else:
y = np.arange(ny)
elif isinstance(y, (list, tuple)):
y = np.array(y)
r = MeteoMath.divergence(u.asarray(), v.asarray(), x.asarray(), y.asarray())
if isinstance(u, DimArray):
return DimArray(NDArray(r), u.dims, u.fill_value, u.proj)
else:
return NDArray(r)
def vorticity(u, v, x=None, y=None):
"""
Calculates the vertical component of the curl (ie, vorticity). The data should be lon/lat projection.
:param u: (*array*) U component array (2D).
:param v: (*array*) V component array (2D).
:param x: (*array*) X coordinate array (1D).
:param y: (*array*) Y coordinate array (1D).
:returns: Array of the vertical component of the curl.
"""
ny = u.shape[-2]
nx = u.shape[-1]
if x is None:
if isinstance(u, DimArray):
x = u.dimvalue(-1)
else:
x = np.arange(nx)
elif isinstance(x, (list, tuple)):
x = np.array(x)
if y is None:
if isinstance(v, DimArray):
y = u.dimvalue(-2)
else:
y = np.arange(ny)
elif isinstance(y, (list, tuple)):
y = np.array(y)
r = MeteoMath.vorticity(u.asarray(), v.asarray(), x.asarray(), y.asarray())
return DimArray(NDArray(r), u.dims, u.fill_value, u.proj)
def get_slp(wrfin, timeidx=0, units='hPa'):
'''
Return the sea level pressure in the specified units.
This function extracts the necessary variables from the NetCDF file
object in order to perform the calculation.
:param wrfin: (*DimDataFile*) Data file.
:param timeidx: (*int*) Time index.
:param units: (*string*) The desired units.
:returns: (*array*) Sea level pressure.
'''
t = wrfin['T'][timeidx,:,:,:]
p = wrfin['P'][timeidx,:,:,:]
pb = wrfin['PB'][timeidx,:,:,:]
qvapor = wrfin['QVAPOR'][timeidx,:,:,:]
ph = wrfin['PH'][timeidx,:,:,:]
phb = wrfin['PHB'][timeidx,:,:,:]
full_t = t + constants.T_BASE
full_p = p + pb
qvapor[qvapor < 0] = 0.
full_ph = (ph + phb) / constants.g
destag_ph = destagger(full_ph, -3)
tk = meteo.temperature_from_potential_temperature(full_p * 0.01, full_t)
slp = MeteoMath.calSeaPrs(destag_ph.array, tk.array, full_p.array, qvapor.array)
return DimArray(slp, dims=t.dims[1:])
def tc2tf(tc):
"""
Celsius temperature to Fahrenheit temperature
tc: DimArray or NDArray or number
Celsius temperature - degree c
return: DimArray or NDArray or number
Fahrenheit temperature - degree f
"""
if isinstance(tc, NDArray):
r = NDArray(MeteoMath.tc2tf(tc.asarray()))
if isinstance(tc, DimArray):
r = DimArray(r, tc.dims, tc.fill_value, tc.proj)
return r
else:
return MeteoMath.tc2tf(tc)
def tf2tc(tf):
"""
Fahrenheit temperature to Celsius temperature
tf: DimArray or NDArray or number
Fahrenheit temperature - degree f
return: DimArray or NDArray or number
Celsius temperature - degree c
"""
if isinstance(tf, NDArray):
r = NDArray(MeteoMath.tf2tc(tf.asarray()))
if isinstance(tf, DimArray):
r = DimArray(r, tf.dims, tf.fill_value, tf.proj)
return r
else:
return MeteoMath.tf2tc(tf)
def rh2dewpoint(rh, temp):
"""
Calculate dewpoint from relative humidity and temperature
rh: DimArray or NDArray or number
Relative humidity - %
temp: DimArray or NDArray or number
Temperature - degree c
return: DimArray or NDArray or number
Relative humidity - %
"""
if isinstance(rh, NDArray):
r = NDArray(MeteoMath.rh2dewpoint(rh.asarray(), temp.asarray()))
if isinstance(rh, DimArray):
r = DimArray(r, rh.dims, rh.fill_value, rh.proj)
return r
else:
return MeteoMath.rh2dewpoint(rh, temp)
def dewpoint2rh(dewpoint, temp):
"""
Dew point to relative humidity
dewpoint: DimArray or NDArray or number
Dew point - degree c
temp: DimArray or NDArray or number
Temperature - degree c
return: DimArray or NDArray or number
Relative humidity - %
"""
if isinstance(dewpoint, NDArray):
r = NDArray(MeteoMath.dewpoint2rh(dewpoint.asarray(), temp.asarray()))
if isinstance(dewpoint, DimArray):
r = DimArray(r, dewpoint.dims, dewpoint.fill_value, dewpoint.proj)
return r
else:
return MeteoMath.dewpoint2rh(temp, dewpoint)
def ds2uv(d, s):
'''
Calculate U/V from wind direction and wind speed.
:param d: (*array_like*) Wind direction.
:param s: (*array_like*) Wind speed.
:returns: Wind U/V.
'''
if isinstance(d, NDArray):
r = MeteoMath.ds2uv(d.asarray(), s.asarray())
u = NDArray(r[0])
v = NDArray(r[1])
if isinstance(d, DimArray) and isinstance(s, DimArray):
u = DimArray(u, d.dims, d.fill_value, d.proj)
v = DimArray(v, d.dims, d.fill_value, d.proj)
return u, v
else:
r = MeteoMath.ds2uv(d, s)
return r[0], r[1]
def uv2ds(u, v):
'''
Calculate wind direction and wind speed from U/V.
:param u: (*array_like*) U component of wind field.
:param v: (*array_like*) V component of wind field.
:returns: Wind direction and wind speed.
'''
if isinstance(u, NDArray):
r = MeteoMath.uv2ds(u.asarray(), v.asarray())
d = NDArray(r[0])
s = NDArray(r[1])
if isinstance(u, DimArray) and isinstance(v, DimArray):
d = DimArray(d, u.dims, u.fill_value, u.proj)
s = DimArray(s, u.dims, u.fill_value, u.proj)
return d, s
else:
r = MeteoMath.uv2ds(u, v)
return r[0], r[1]
def cdiff(a, dimidx):
'''
Performs a centered difference operation on a array in a specific direction
:param a: (*array*) The input array.
:param dimidx: (*int*) Demension index of the specific direction.
:returns: Result array.
'''
r = MeteoMath.cdiff(a.asarray(), dimidx)
if isinstance(a, DimArray):
return DimArray(NDArray(r), a.dims, a.fill_value, a.proj)
else:
return NDArray(r)
