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Update thickness_hydrostatic to have an option to return full profile #3148

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Update thickness_hydrostatic to have an option to return full profile #3148

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62 changes: 36 additions & 26 deletions src/metpy/calc/thermo.py
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Original file line number Diff line number Diff line change
Expand Up @@ -3338,16 +3338,9 @@ def moist_static_energy(height, temperature, specific_humidity):
)
def thickness_hydrostatic(pressure, temperature, mixing_ratio=None,
molecular_weight_ratio=mpconsts.nounit.epsilon, bottom=None,
depth=None):
depth=None, full_profile=False):
r"""Calculate the thickness of a layer via the hypsometric equation.

This thickness calculation uses the pressure and temperature profiles (and optionally
mixing ratio) via the hypsometric equation with virtual temperature adjustment.

.. math:: Z_2 - Z_1 = -\frac{R_d}{g} \int_{p_1}^{p_2} T_v d\ln p,

Which is based off of Equation 3.24 in [Hobbs2006]_.

This assumes a hydrostatic atmosphere. Layer bottom and depth specified in pressure.

Parameters
Expand All @@ -3374,6 +3367,12 @@ def thickness_hydrostatic(pressure, temperature, mixing_ratio=None,
The depth of the layer in hPa. Defaults to the full profile if bottom is not given,
and 100 hPa if bottom is given.

full_profile : `bool`, optional
Controls whether or not to return the full thickness profile, i.e., the thickness
between individual layers as a `Pint.Quantity` array or the thickness of
the whole atmospheric profile as a `Pint.Quantity`. Defaults to False, which returns
the thickness of the atmosphere as a single value.

Returns
-------
`pint.Quantity`
Expand Down Expand Up @@ -3427,6 +3426,13 @@ def thickness_hydrostatic(pressure, temperature, mixing_ratio=None,
Since this function returns scalar values when given a profile, this will return Pint
Quantities even when given xarray DataArray profiles.

This thickness calculation uses the pressure and temperature profiles (and optionally
mixing ratio) via the hypsometric equation with virtual temperature adjustment.

.. math:: Z_2 - Z_1 = -\frac{R_d}{g} \int_{p_1}^{p_2} T_v d\ln p,

Which is based off of Equation 3.24 in [Hobbs2006]_.

.. versionchanged:: 1.0
Renamed ``mixing`` parameter to ``mixing_ratio``

Expand Down Expand Up @@ -3470,31 +3476,21 @@ def thickness_hydrostatic(pressure, temperature, mixing_ratio=None,
)

# Take the integral
return (
-mpconsts.nounit.Rd / mpconsts.nounit.g
* np.trapz(layer_virttemp, np.log(layer_p))
)
diff_logp = np.diff(np.log(layer_p))
thickness = (-mpconsts.nounit.Rd / mpconsts.nounit.g * diff_logp * (
layer_virttemp[1:] + layer_virttemp[:-1]) / 2.)

return thickness if full_profile else np.sum(thickness)


@exporter.export
@preprocess_and_wrap()
@check_units('[pressure]', '[temperature]')
def thickness_hydrostatic_from_relative_humidity(pressure, temperature, relative_humidity,
bottom=None, depth=None):
bottom=None, depth=None, full_profile=False):
r"""Calculate the thickness of a layer given pressure, temperature and relative humidity.

Similar to ``thickness_hydrostatic``, this thickness calculation uses the pressure,
temperature, and relative humidity profiles via the hypsometric equation with virtual
temperature adjustment

.. math:: Z_2 - Z_1 = -\frac{R_d}{g} \int_{p_1}^{p_2} T_v d\ln p,

which is based off of Equation 3.24 in [Hobbs2006]_. Virtual temperature is calculated
from the profiles of temperature and relative humidity.

This assumes a hydrostatic atmosphere.

Layer bottom and depth specified in pressure.
This assumes a hydrostatic atmosphere. Layer bottom and depth specified in pressure.

Parameters
----------
Expand All @@ -3516,6 +3512,12 @@ def thickness_hydrostatic_from_relative_humidity(pressure, temperature, relative
The depth of the layer in hPa. Defaults to the full profile if bottom is not given,
and 100 hPa if bottom is given.

full_profile : `bool`, optional
Controls whether or not to return the full thickness profile, i.e., the thickness
between individual layers as a `Pint.Quantity` array or the thickness of
the whole atmospheric profile as a `Pint.Quantity`. Defaults to False, which returns
the thickness of the atmosphere as a single value.

Returns
-------
`pint.Quantity`
Expand Down Expand Up @@ -3557,11 +3559,19 @@ def thickness_hydrostatic_from_relative_humidity(pressure, temperature, relative
Since this function returns scalar values when given a profile, this will return Pint
Quantities even when given xarray DataArray profiles.

Similar to ``thickness_hydrostatic``, this thickness calculation uses the pressure,
temperature, and relative humidity profiles via the hypsometric equation with virtual
temperature adjustment

.. math:: Z_2 - Z_1 = -\frac{R_d}{g} \int_{p_1}^{p_2} T_v d\ln p,

which is based off of Equation 3.24 in [Hobbs2006]_. Virtual temperature is calculated
from the profiles of temperature and relative humidity.
"""
mixing = mixing_ratio_from_relative_humidity(pressure, temperature, relative_humidity)

return thickness_hydrostatic(pressure, temperature, mixing_ratio=mixing, bottom=bottom,
depth=depth)
depth=depth, full_profile=full_profile)


@exporter.export
Expand Down
11 changes: 11 additions & 0 deletions tests/calc/test_thermo.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1607,6 +1607,17 @@ def test_thickness_hydrostatic_isothermal_subset():
assert_almost_equal(thickness, 4242.527 * units.m, 2)


def test_thickness_hydrostatic_full_profile():
"""Test the thickness calculation for a moist layer."""
pressure = np.array([959., 779.2, 751.3, 724.3, 700., 269.]) * units.hPa
temperature = np.array([22.2, 14.6, 12., 9.4, 7., -38.]) * units.degC
mixing = np.array([0.01458, 0.00209, 0.00224, 0.00240, 0.00256, 0.00010])
thickness = thickness_hydrostatic(pressure, temperature, mixing_ratio=mixing,
full_profile=True)
result = [1780.778, 306.126, 304.513, 281.455, 7218.833] * units.m
assert_almost_equal(thickness, result, 2)


def test_thickness_hydrostatic_from_relative_humidity():
"""Test the thickness calculation for a moist layer using RH data."""
pressure = np.array([959., 779.2, 751.3, 724.3, 700., 269.]) * units.hPa
Expand Down