.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "examples/calculations/Mountain_Problem.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download_examples_calculations_Mountain_Problem.py>`
        to download the full example code

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_examples_calculations_Mountain_Problem.py:


================
Mountain Problem
================

Use functions from `metpy.calc` to perform calculations for a rising and sinking parcel.

The code below explores a common problem in meteorology where a parcel can be defined and
lifted initiatlly dry adibatically until saturation is reached. It then ascends moist
adiabatically to a desired level before descending back to the original level from which the
parcel started.

.. GENERATED FROM PYTHON SOURCE LINES 16-21

.. code-block:: Python

    import numpy as np

    from metpy.calc import dry_lapse, lcl, moist_lapse
    from metpy.units import units








.. GENERATED FROM PYTHON SOURCE LINES 22-24

To set up the classic mountain problem, let's define that the parcel will start at 1000-hPa
and ascend to 700-hPa with an initial temperature of 25 Celsius and a dewpoint of 10 Celsius

.. GENERATED FROM PYTHON SOURCE LINES 24-29

.. code-block:: Python


    p = np.linspace(1000, 700, 301) * units.hPa
    T = 25 * units.degC
    Td = 10 * units.degC








.. GENERATED FROM PYTHON SOURCE LINES 30-32

We first need to determine the maximum level of dry ascent. For this we can use the LCL
function and retain the pressure level and temperature of the parcel at the LCL

.. GENERATED FROM PYTHON SOURCE LINES 32-38

.. code-block:: Python

    lclp, lclt = lcl(p[0], T, Td)
    print('Initial dry ascent yields:')
    print(f'  LCL Pressure: {lclp:.2f}')
    print(f'  LCL Temperature: {lclt:.2f}')
    print()





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    Initial dry ascent yields:
      LCL Pressure: 801.54 hectopascal
      LCL Temperature: 6.74 degree_Celsius





.. GENERATED FROM PYTHON SOURCE LINES 39-43

Knowing that the calculation of the dry ascent is accomplished by the LCL calculation, we
know how to begin our moist ascent. Begin by subsetting the pressure to begin at levels
less than or equal to the LCL pressure and use the moist_lapse to find the temperature
at the top of our ascent (700-hPa in our case)

.. GENERATED FROM PYTHON SOURCE LINES 43-49

.. code-block:: Python

    moist_ascent_p = p[p <= lclp]
    moist_ascent_t = moist_lapse(moist_ascent_p, lclt)
    print('After moist ascent:')
    print(f'  Temperature at top of ascent: {moist_ascent_t[-1]:.2f}')
    print()





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    After moist ascent:
      Temperature at top of ascent: 0.82 degree_Celsius





.. GENERATED FROM PYTHON SOURCE LINES 50-53

Now to come "down the mountain" our parcel will warm dry adiabatically, so we can use the
dry_laspe function to descend from the lowest pressure (using [::-1] to reverse the order)
and convert our solution to Celsius

.. GENERATED FROM PYTHON SOURCE LINES 53-55

.. code-block:: Python

    dry_descent = dry_lapse(p[::-1], moist_ascent_t[-1]).to('degC')








.. GENERATED FROM PYTHON SOURCE LINES 56-57

Pulling it all together

.. GENERATED FROM PYTHON SOURCE LINES 57-62

.. code-block:: Python

    print(f'Starting Temperature: {T:.2f}')
    print(f'Starting Dewpoint: {Td:.2f}', end='\n\n')
    print(f'Final Temperature: {dry_descent[-1]:.2f}')
    print(f'Final Dewpoint: {moist_ascent_t[-1]:.2f}')





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    Starting Temperature: 25.00 degree_Celsius
    Starting Dewpoint: 10.00 degree_Celsius

    Final Temperature: 30.21 degree_Celsius
    Final Dewpoint: 0.82 degree_Celsius




.. GENERATED FROM PYTHON SOURCE LINES 63-66

So as we expect the parcel has warmed and dried out through the combined dry and moist ascent
due to the release of latent heat and subsequent precipitating out of moisture from the
parcel


.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 0.006 seconds)


.. _sphx_glr_download_examples_calculations_Mountain_Problem.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: Mountain_Problem.ipynb <Mountain_Problem.ipynb>`

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: Mountain_Problem.py <Mountain_Problem.py>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_