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test_lfc_equals_lcl()   A

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# Copyright (c) 2008-2015 MetPy Developers.
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# Distributed under the terms of the BSD 3-Clause License.
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# SPDX-License-Identifier: BSD-3-Clause
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"""Test the `thermo` module."""
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import numpy as np
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import pytest
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from metpy.calc import (density, dewpoint, dewpoint_rh, dry_lapse, el,
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                        equivalent_potential_temperature, lcl, lfc, mixing_ratio,
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                        mixing_ratio_from_specific_humidity, moist_lapse,
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                        parcel_profile, potential_temperature,
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                        psychrometric_vapor_pressure_wet,
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                        relative_humidity_from_mixing_ratio,
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                        relative_humidity_from_specific_humidity,
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                        relative_humidity_wet_psychrometric,
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                        saturation_mixing_ratio,
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                        saturation_vapor_pressure, vapor_pressure,
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                        virtual_potential_temperature, virtual_temperature)
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from metpy.testing import assert_almost_equal, assert_array_almost_equal, assert_nan
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from metpy.units import units
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def test_potential_temperature():
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    """Test potential_temperature calculation."""
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    temp = np.array([278., 283., 291., 298.]) * units.kelvin
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    pres = np.array([900., 500., 300., 100.]) * units.mbar
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    real_th = np.array([286.493, 344.961, 410.4335, 575.236]) * units.kelvin
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    assert_array_almost_equal(potential_temperature(pres, temp), real_th, 3)
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def test_scalar():
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    """Test potential_temperature accepts scalar values."""
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    assert_almost_equal(potential_temperature(1000. * units.mbar, 293. * units.kelvin),
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                        293. * units.kelvin, 4)
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    assert_almost_equal(potential_temperature(800. * units.mbar, 293. * units.kelvin),
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                        312.2828 * units.kelvin, 4)
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def test_fahrenheit():
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    """Test that potential_temperature handles temperature values in Fahrenheit."""
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    assert_almost_equal(potential_temperature(800. * units.mbar, 68. * units.degF),
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                        (312.444 * units.kelvin).to(units.degF), 2)
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def test_pot_temp_inhg():
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    """Test that potential_temperature can handle pressure not in mb (issue #165)."""
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    assert_almost_equal(potential_temperature(29.92 * units.inHg, 29 * units.degC),
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                        301.019735 * units.kelvin, 4)
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def test_dry_lapse():
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    """Test dry_lapse calculation."""
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    levels = np.array([1000, 900, 864.89]) * units.mbar
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    temps = dry_lapse(levels, 303.15 * units.kelvin)
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    assert_array_almost_equal(temps,
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                              np.array([303.15, 294.16, 290.83]) * units.kelvin, 2)
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def test_dry_lapse_2_levels():
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    """Test dry_lapse calculation when given only two levels."""
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    temps = dry_lapse(np.array([1000., 500.]) * units.mbar, 293. * units.kelvin)
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    assert_array_almost_equal(temps, [293., 240.3723] * units.kelvin, 4)
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def test_moist_lapse():
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    """Test moist_lapse calculation."""
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    temp = moist_lapse(np.array([1000., 800., 600., 500., 400.]) * units.mbar,
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                       293. * units.kelvin)
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    true_temp = np.array([293, 284.64, 272.81, 264.42, 252.91]) * units.kelvin
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    assert_array_almost_equal(temp, true_temp, 2)
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def test_moist_lapse_degc():
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    """Test moist_lapse with Celsius temperatures."""
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    temp = moist_lapse(np.array([1000., 800., 600., 500., 400.]) * units.mbar,
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                       19.85 * units.degC)
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    true_temp = np.array([293, 284.64, 272.81, 264.42, 252.91]) * units.kelvin
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    assert_array_almost_equal(temp, true_temp, 2)
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def test_parcel_profile():
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    """Test parcel profile calculation."""
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    levels = np.array([1000., 900., 800., 700., 600., 500., 400.]) * units.mbar
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    true_prof = np.array([303.15, 294.16, 288.026, 283.073, 277.058, 269.402,
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                          258.966]) * units.kelvin
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    prof = parcel_profile(levels, 30. * units.degC, 20. * units.degC)
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    assert_array_almost_equal(prof, true_prof, 2)
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def test_parcel_profile_saturated():
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    """Test parcel_profile works when LCL in levels (issue #232)."""
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    levels = np.array([1000., 700., 500.]) * units.mbar
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    true_prof = np.array([296.95, 284.381, 271.123]) * units.kelvin
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    prof = parcel_profile(levels, 23.8 * units.degC, 23.8 * units.degC)
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    assert_array_almost_equal(prof, true_prof, 2)
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def test_sat_vapor_pressure():
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    """Test saturation_vapor_pressure calculation."""
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    temp = np.array([5., 10., 18., 25.]) * units.degC
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    real_es = np.array([8.72, 12.27, 20.63, 31.67]) * units.mbar
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    assert_array_almost_equal(saturation_vapor_pressure(temp), real_es, 2)
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def test_sat_vapor_pressure_scalar():
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    """Test saturation_vapor_pressure handles scalar values."""
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    es = saturation_vapor_pressure(0 * units.degC)
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    assert_almost_equal(es, 6.112 * units.mbar, 3)
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def test_sat_vapor_pressure_fahrenheit():
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    """Test saturation_vapor_pressure handles temperature in Fahrenheit."""
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    temp = np.array([50., 68.]) * units.degF
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    real_es = np.array([12.2717, 23.3695]) * units.mbar
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    assert_array_almost_equal(saturation_vapor_pressure(temp), real_es, 4)
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def test_basic_dewpoint_rh():
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    """Test dewpoint_rh function."""
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    temp = np.array([30., 25., 10., 20., 25.]) * units.degC
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    rh = np.array([30., 45., 55., 80., 85.]) / 100.
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    real_td = np.array([11, 12, 1, 16, 22]) * units.degC
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    assert_array_almost_equal(real_td, dewpoint_rh(temp, rh), 0)
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def test_scalar_dewpoint_rh():
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    """Test dewpoint_rh with scalar values."""
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    td = dewpoint_rh(10.6 * units.degC, 0.37)
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    assert_almost_equal(td, 26. * units.degF, 0)
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def test_dewpoint():
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    """Test dewpoint calculation."""
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    assert_almost_equal(dewpoint(6.112 * units.mbar), 0. * units.degC, 2)
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def test_dewpoint_weird_units():
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    """Test dewpoint using non-standard units.
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    Revealed from odd dimensionless units and ending up using numpy.ma math
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    functions instead of numpy ones.
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    """
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    assert_almost_equal(dewpoint(15825.6 * units('g * mbar / kg')),
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                        13.8564 * units.degC, 4)
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def test_mixing_ratio():
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    """Test mixing ratio calculation."""
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    p = 998. * units.mbar
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    e = 73.75 * units.mbar
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    assert_almost_equal(mixing_ratio(e, p), 0.04963, 2)
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def test_vapor_pressure():
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    """Test vapor pressure calculation."""
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    assert_almost_equal(vapor_pressure(998. * units.mbar, 0.04963),
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                        73.74925 * units.mbar, 5)
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def test_lcl():
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    """Test LCL calculation."""
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    lcl_pressure, lcl_temperature = lcl(1000. * units.mbar, 30. * units.degC, 20. * units.degC)
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    assert_almost_equal(lcl_pressure, 864.761 * units.mbar, 2)
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    assert_almost_equal(lcl_temperature, 17.676 * units.degC, 2)
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def test_lcl_convergence():
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    """Test LCL calculation convergence failure."""
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    with pytest.raises(RuntimeError):
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        lcl(1000. * units.mbar, 30. * units.degC, 20. * units.degC, max_iters=2)
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def test_lfc_basic():
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    """Test LFC calculation."""
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    levels = np.array([959., 779.2, 751.3, 724.3, 700., 269.]) * units.mbar
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    temperatures = np.array([22.2, 14.6, 12., 9.4, 7., -49.]) * units.celsius
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    dewpoints = np.array([19., -11.2, -10.8, -10.4, -10., -53.2]) * units.celsius
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    l = lfc(levels, temperatures, dewpoints)
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    assert_almost_equal(l[0], 727.468 * units.mbar, 2)
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    assert_almost_equal(l[1], 9.705 * units.celsius, 2)
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def test_no_lfc():
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    """Test LFC calculation when there is no LFC in the data."""
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    levels = np.array([959., 867.9, 779.2, 647.5, 472.5, 321.9, 251.]) * units.mbar
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    temperatures = np.array([22.2, 17.4, 14.6, 1.4, -17.6, -39.4, -52.5]) * units.celsius
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    dewpoints = np.array([9., 4.3, -21.2, -26.7, -31., -53.3, -66.7]) * units.celsius
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    lfc_pressure, lfc_temperature = lfc(levels, temperatures, dewpoints)
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    assert assert_nan(lfc_pressure, levels.units)
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    assert assert_nan(lfc_temperature, temperatures.units)
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def test_lfc_inversion():
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    """Test LFC when there is an inversion to be sure we don't pick that."""
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    levels = np.array([963., 789., 782.3, 754.8, 728.1, 727., 700.,
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                       571., 450., 300., 248.]) * units.mbar
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    temperatures = np.array([25.4, 18.4, 17.8, 15.4, 12.9, 12.8,
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                             10., -3.9, -16.3, -41.1, -51.5]) * units.celsius
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    dewpoints = np.array([20.4, 0.4, -0.5, -4.3, -8., -8.2, -9.,
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                          -23.9, -33.3, -54.1, -63.5]) * units.celsius
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    l = lfc(levels, temperatures, dewpoints)
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    assert_almost_equal(l[0], 706.0103 * units.mbar, 2)
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    assert_almost_equal(l[1], 10.6232 * units.celsius, 2)
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def test_lfc_equals_lcl():
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    """Test LFC when there is no cap and the lfc is equal to the lcl."""
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    levels = np.array([912., 905.3, 874.4, 850., 815.1, 786.6, 759.1,
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                       748., 732.2, 700., 654.8]) * units.mbar
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    temperatures = np.array([29.4, 28.7, 25.2, 22.4, 19.4, 16.8,
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                             14.3, 13.2, 12.6, 11.4, 7.1]) * units.celsius
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    dewpoints = np.array([18.4, 18.1, 16.6, 15.4, 13.2, 11.4, 9.6,
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                          8.8, 0., -18.6, -22.9]) * units.celsius
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    l = lfc(levels, temperatures, dewpoints)
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    assert_almost_equal(l[0], 777.0333 * units.mbar, 2)
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    assert_almost_equal(l[1], 15.8714 * units.celsius, 2)
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def test_saturation_mixing_ratio():
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    """Test saturation mixing ratio calculation."""
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    p = 999. * units.mbar
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    t = 288. * units.kelvin
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    assert_almost_equal(saturation_mixing_ratio(p, t), .01068, 3)
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def test_equivalent_potential_temperature():
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    """Test equivalent potential temperature calculation."""
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    p = 999. * units.mbar
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    t = 288. * units.kelvin
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    ept = equivalent_potential_temperature(p, t)
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    assert_almost_equal(ept, 315.9548 * units.kelvin, 3)
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def test_virtual_temperature():
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    """Test virtual temperature calculation."""
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    t = 288. * units.kelvin
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    qv = .0016  # kg/kg
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    tv = virtual_temperature(t, qv)
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    assert_almost_equal(tv, 288.2796 * units.kelvin, 3)
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def test_virtual_potential_temperature():
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    """Test virtual potential temperature calculation."""
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    p = 999. * units.mbar
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    t = 288. * units.kelvin
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    qv = .0016  # kg/kg
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    theta_v = virtual_potential_temperature(p, t, qv)
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    assert_almost_equal(theta_v, 288.3620 * units.kelvin, 3)
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def test_density():
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    """Test density calculation."""
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    p = 999. * units.mbar
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    t = 288. * units.kelvin
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    qv = .0016  # kg/kg
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    rho = density(p, t, qv).to(units.kilogram / units.meter ** 3)
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    assert_almost_equal(rho, 1.2072 * (units.kilogram / units.meter ** 3), 3)
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def test_el():
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    """Test equilibrium layer calculation."""
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    levels = np.array([959., 779.2, 751.3, 724.3, 700., 269.]) * units.mbar
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    temperatures = np.array([22.2, 14.6, 12., 9.4, 7., -38.]) * units.celsius
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    dewpoints = np.array([19., -11.2, -10.8, -10.4, -10., -53.2]) * units.celsius
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    el_pressure, el_temperature = el(levels, temperatures, dewpoints)
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    assert_almost_equal(el_pressure, 520.8700 * units.mbar, 3)
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    assert_almost_equal(el_temperature, -11.7027 * units.degC, 3)
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def test_no_el():
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    """Test equilibrium layer calculation when there is no EL in the data."""
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    levels = np.array([959., 867.9, 779.2, 647.5, 472.5, 321.9, 251.]) * units.mbar
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    temperatures = np.array([22.2, 17.4, 14.6, 1.4, -17.6, -39.4, -52.5]) * units.celsius
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    dewpoints = np.array([19., 14.3, -11.2, -16.7, -21., -43.3, -56.7]) * units.celsius
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    el_pressure, el_temperature = el(levels, temperatures, dewpoints)
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    assert assert_nan(el_pressure, levels.units)
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    assert assert_nan(el_temperature, temperatures.units)
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def test_el_lfc_equals_lcl():
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    """Test equilibrium layer calculation when the lfc equals the lcl."""
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    levels = np.array([912., 905.3, 874.4, 850., 815.1, 786.6, 759.1, 748.,
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                       732.3, 700., 654.8, 606.8, 562.4, 501.8, 500., 482.,
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                       400., 393.3, 317.1, 307., 300., 252.7, 250., 200.,
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                       199.3, 197., 190., 172., 156.6, 150., 122.9, 112.,
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                       106.2, 100.]) * units.mbar
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    temperatures = np.array([29.4, 28.7, 25.2, 22.4, 19.4, 16.8, 14.3,
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                             13.2, 12.6, 11.4, 7.1, 2.2, -2.7, -10.1,
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                             -10.3, -12.4, -23.3, -24.4, -38., -40.1, -41.1,
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                             -49.8, -50.3, -59.1, -59.1, -59.3, -59.7, -56.3,
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                             -56.9, -57.1, -59.1, -60.1, -58.6, -56.9]) * units.celsius
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    dewpoints = np.array([18.4, 18.1, 16.6, 15.4, 13.2, 11.4, 9.6, 8.8, 0.,
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                          -18.6, -22.9, -27.8, -32.7, -40.1, -40.3, -42.4, -53.3,
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                          -54.4, -68., -70.1, -70., -70., -70., -70., -70., -70.,
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                          -70., -70., -70., -70., -70., -70., -70., -70.]) * units.celsius
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    el_pressure, el_temperature = el(levels, temperatures, dewpoints)
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    assert_almost_equal(el_pressure, 175.8684 * units.mbar, 3)
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    assert_almost_equal(el_temperature, -57.0307 * units.degC, 3)
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def test_wet_psychrometric_vapor_pressure():
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    """Test calculation of vapor pressure from wet and dry bulb temperatures."""
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    p = 1013.25 * units.mbar
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    dry_bulb_temperature = 20. * units.degC
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    wet_bulb_temperature = 18. * units.degC
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    psychrometric_vapor_pressure = psychrometric_vapor_pressure_wet(dry_bulb_temperature,
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                                                                    wet_bulb_temperature, p)
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    assert_almost_equal(psychrometric_vapor_pressure, 19.3673 * units.mbar, 3)
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def test_wet_psychrometric_rh():
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    """Test calculation of relative humidity from wet and dry bulb temperatures."""
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    p = 1013.25 * units.mbar
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    dry_bulb_temperature = 20. * units.degC
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    wet_bulb_temperature = 18. * units.degC
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    psychrometric_rh = relative_humidity_wet_psychrometric(dry_bulb_temperature,
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                                                           wet_bulb_temperature, p)
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    assert_almost_equal(psychrometric_rh, 82.8747 * units.percent, 3)
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def test_wet_psychrometric_rh_kwargs():
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    """Test calculation of relative humidity from wet and dry bulb temperatures."""
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    p = 1013.25 * units.mbar
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    dry_bulb_temperature = 20. * units.degC
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    wet_bulb_temperature = 18. * units.degC
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    coeff = 6.1e-4 / units.kelvin
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    psychrometric_rh = relative_humidity_wet_psychrometric(dry_bulb_temperature,
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                                                           wet_bulb_temperature, p,
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                                                           psychrometer_coefficient=coeff)
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    assert_almost_equal(psychrometric_rh, 82.9701 * units.percent, 3)
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def test_rh_mixing_ratio():
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    """Tests relative humidity from mixing ratio."""
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    p = 1013.25 * units.mbar
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    temperature = 20. * units.degC
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    w = 0.012
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    rh = relative_humidity_from_mixing_ratio(w, temperature, p)
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    assert_almost_equal(rh, 81.7219 * units.percent, 3)
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def test_mixing_ratio_from_specific_humidity():
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    """Tests mixing ratio from specific humidity."""
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    q = 0.012
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    w = mixing_ratio_from_specific_humidity(q)
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    assert_almost_equal(w, 0.01215, 3)
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def test_rh_specific_humidity():
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    """Tests relative humidity from specific humidity."""
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    p = 1013.25 * units.mbar
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    temperature = 20. * units.degC
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    q = 0.012
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    rh = relative_humidity_from_specific_humidity(q, temperature, p)
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    assert_almost_equal(rh, 82.7145 * units.percent, 3)
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