.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "api/gallery/climate/plot_14_myhre_forcing_formulas.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_climate_plot_14_myhre_forcing_formulas.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_climate_plot_14_myhre_forcing_formulas.py:


Myhre's forcing formulas (1998)
===============================

Gunnar Myhre and colleagues fitted simple expressions to line-by-line
radiative calculations for the well-mixed greenhouse gases. CO2 forcing is
logarithmic, ``5.35 ln(C / C0)``, because its strongest bands are saturated.
Methane and nitrous oxide grow with the square root of concentration, less a
term for the band near 7.7 μm that they share. The IPCC adopted the
formulas in 2001; from 1750 to 1998 they give about 1.46, 0.48 and 0.15
W/m² for the three gases.

.. GENERATED FROM PYTHON SOURCE LINES 13-41



.. image-sg:: /api/gallery/climate/images/sphx_glr_plot_14_myhre_forcing_formulas_001.png
   :alt: Well-mixed greenhouse gases
   :srcset: /api/gallery/climate/images/sphx_glr_plot_14_myhre_forcing_formulas_001.png
   :class: sphx-glr-single-img





.. code-block:: Python


    import matplotlib.pyplot as plt
    import numpy as np

    from earthsciencekit.climate import co2_forcing, methane_forcing, nitrous_oxide_forcing

    values = {
        "CO2": co2_forcing(365, 278, 5.35),
        "CH4": methane_forcing(1745, 700, 270),
        "N2O": nitrous_oxide_forcing(314, 270, 700),
    }
    np.testing.assert_allclose(list(values.values()), [1.46, 0.48, 0.15], atol=0.01)
    ratio = np.linspace(1, 3, 101)
    overlap_free = methane_forcing(700 * ratio, 700, 1e-6)
    with_overlap = methane_forcing(700 * ratio, 700, 270)
    assert np.all(with_overlap[1:] < overlap_free[1:])

    fig, (left, right) = plt.subplots(1, 2, figsize=(10, 4))
    left.bar(list(values), list(values.values()), color=["C0", "C1", "C2"])
    left.set(ylabel="forcing 1750-1998 [W/m²]", title="Well-mixed greenhouse gases")
    right.plot(ratio, co2_forcing(278 * ratio, 278, 5.35), label="CO2, logarithmic")
    right.plot(ratio, overlap_free, "--", label="CH4 without N2O overlap")
    right.plot(ratio, with_overlap, label="CH4, square root less overlap")
    right.set(xlabel="concentration relative to 1750", ylabel="forcing [W/m²]")
    right.legend()
    fig.tight_layout()

    plt.show()


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

   **Total running time of the script:** (0 minutes 0.191 seconds)


.. _sphx_glr_download_api_gallery_climate_plot_14_myhre_forcing_formulas.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/climate/plot_14_myhre_forcing_formulas.ipynb
        :alt: Launch JupyterLite
        :width: 150 px

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

      :download:`Download Jupyter notebook: plot_14_myhre_forcing_formulas.ipynb <plot_14_myhre_forcing_formulas.ipynb>`

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

      :download:`Download Python source code: plot_14_myhre_forcing_formulas.py <plot_14_myhre_forcing_formulas.py>`

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

      :download:`Download zipped: plot_14_myhre_forcing_formulas.zip <plot_14_myhre_forcing_formulas.zip>`


.. only:: html

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

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