.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "api/gallery/glaciology/plot_01_agassiz_ice_age.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

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

        :ref:`Go to the end <sphx_glr_download_api_gallery_glaciology_plot_01_agassiz_ice_age.py>`
        to download the full example code or to run this example in your browser via JupyterLite.

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

.. _sphx_glr_api_gallery_glaciology_plot_01_agassiz_ice_age.py:


Agassiz's ice age (1840)
========================

Louis Agassiz read the erratic boulders, polished rock and moraines of the
Jura as the work of glaciers far larger than those of the Alps today, and
proposed a great ice age. A modest cooling is enough: the equilibrium line,
above which snow survives the summer, falls by the cooling divided by the
lapse rate, and the area of a mountain range above it grows quickly. The
example uses a synthetic range with a normal distribution of elevations.

.. GENERATED FROM PYTHON SOURCE LINES 12-34



.. image-sg:: /api/gallery/glaciology/images/sphx_glr_plot_01_agassiz_ice_age_001.png
   :alt: The snow line comes down, Agassiz: a small cooling, a large ice cover
   :srcset: /api/gallery/glaciology/images/sphx_glr_plot_01_agassiz_ice_age_001.png
   :class: sphx-glr-single-img





.. code-block:: Python


    import matplotlib.pyplot as plt
    import numpy as np
    from scipy.stats import norm

    from earthsciencekit.glaciology import ela_shift

    present_ela, lapse_rate = 2900.0, 0.0065  # m, K/m
    mean_elevation, spread = 1400.0, 700.0  # m, of the range
    cooling = np.linspace(0, 10, 101)
    ela = present_ela + ela_shift(-cooling, lapse_rate)
    fraction = norm.sf(ela, mean_elevation, spread)
    assert np.isclose(ela_shift(-6.5, lapse_rate), -1000) and fraction[-1] > 20 * fraction[0]

    fig, (left, right) = plt.subplots(1, 2, figsize=(10, 4))
    left.plot(cooling, ela, color="tab:blue")
    left.set(xlabel="summer cooling [K]", ylabel="equilibrium-line altitude [m]", title="The snow line comes down")
    right.semilogy(cooling, 100 * fraction, color="tab:cyan")
    right.set(xlabel="summer cooling [K]", ylabel="area above the line [%]", title="Agassiz: a small cooling, a large ice cover")
    fig.tight_layout()

    plt.show()


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

   **Total running time of the script:** (0 minutes 0.258 seconds)


.. _sphx_glr_download_api_gallery_glaciology_plot_01_agassiz_ice_age.py:

.. only:: html

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

    .. container:: lite-badge

      .. image:: images/jupyterlite_badge_logo.svg
        :target: ../../../lite/lab/index.html?path=api/gallery/glaciology/plot_01_agassiz_ice_age.ipynb
        :alt: Launch JupyterLite
        :width: 150 px

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

      :download:`Download Jupyter notebook: plot_01_agassiz_ice_age.ipynb <plot_01_agassiz_ice_age.ipynb>`

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

      :download:`Download Python source code: plot_01_agassiz_ice_age.py <plot_01_agassiz_ice_age.py>`

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: plot_01_agassiz_ice_age.zip <plot_01_agassiz_ice_age.zip>`


.. only:: html

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

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