=================
Advanced Sounding
=================
`Notebook <http://nbviewer.ipython.org/github/metpy/MetPy/blob/master/examples/notebooks/Advanced_Sounding.ipynb>`_

.. code:: ipython3

    import matplotlib.pyplot as plt
    import numpy as np
    
    from metpy.cbook import get_test_data
    from metpy.calc import get_wind_components, lcl, dry_lapse, parcel_profile
    from metpy.plots import SkewT
    from metpy.units import units, concatenate

.. code:: ipython3

    # Parse the data
    p, T, Td, direc, spd = np.loadtxt(get_test_data('may3_sounding.txt'),
            usecols=(0, 2, 3, 6, 7), unpack=True)

.. code:: ipython3

    # Add units to the data arrays
    p = p * units.mbar
    T = T * units.degC
    Td = Td * units.degC
    spd = spd * units.knot
    direc = direc * units.deg

.. code:: ipython3

    # Convert wind speed and direction to components
    u, v = get_wind_components(spd, direc)

.. code:: ipython3

    # Create a new figure. The dimensions here give a good aspect ratio
    fig = plt.figure(figsize=(9, 9))
    skew = SkewT(fig, rotation=45)
    
    # Plot the data using normal plotting functions, in this case using
    # log scaling in Y, as dictated by the typical meteorological plot
    skew.plot(p, T, 'r')
    skew.plot(p, Td, 'g')
    skew.plot_barbs(p, u, v)
    skew.ax.set_ylim(1000, 100)
    skew.ax.set_xlim(-40, 60)
    
    # Calculate LCL height and plot as black dot
    l = lcl(p[0], T[0], Td[0])
    lcl_temp = dry_lapse(concatenate((p[0], l)), T[0])[-1].to('degC')
    skew.plot(l, lcl_temp, 'ko', markerfacecolor='black')
    
    # Calculate full parcel profile and add to plot as black line
    prof = parcel_profile(p, T[0], Td[0]).to('degC')
    skew.plot(p, prof, 'k', linewidth=2)
    
    # Example of coloring area between profiles
    skew.ax.fill_betweenx(p, T, prof, where=T>=prof, facecolor='blue', alpha=0.4)
    skew.ax.fill_betweenx(p, T, prof, where=T<prof, facecolor='red', alpha=0.4)
    
    # An example of a slanted line at constant T -- in this case the 0
    # isotherm
    l = skew.ax.axvline(0, color='c', linestyle='--', linewidth=2)
    
    # Add the relevant special lines
    skew.plot_dry_adiabats()
    skew.plot_moist_adiabats()
    skew.plot_mixing_lines()
    
    # Show the plot
    plt.show()



.. image:: Advanced_Sounding_files/Advanced_Sounding_4_0.png