.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "api/gallery/climate/plot_01_fourier_greenhouse.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_01_fourier_greenhouse.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_01_fourier_greenhouse.py:


Fourier's greenhouse (1824)
===========================

Joseph Fourier argued that the Earth would be much colder if it simply
radiated away the sunlight it absorbs, and that the atmosphere must hold heat
in. A planet in radiative balance emits what it absorbs, which for the
present albedo of about 0.3 gives an effective temperature near 255 K. The
measured mean surface temperature of about 288 K is 33 K warmer; that gap is
the greenhouse effect.

.. GENERATED FROM PYTHON SOURCE LINES 12-35



.. image-sg:: /api/gallery/climate/images/sphx_glr_plot_01_fourier_greenhouse_001.png
   :alt: The Earth is warmer than radiative balance allows
   :srcset: /api/gallery/climate/images/sphx_glr_plot_01_fourier_greenhouse_001.png
   :class: sphx-glr-single-img





.. code-block:: Python


    import matplotlib.pyplot as plt
    import numpy as np

    from earthsciencekit.climate import absorbed_solar, effective_temperature, outgoing_longwave

    albedo = np.linspace(0, 0.8, 201)
    flux = absorbed_solar(1361, albedo)
    temperature = effective_temperature(flux, 1)
    np.testing.assert_allclose(outgoing_longwave(temperature, 1), flux, rtol=1e-14)
    earth = float(effective_temperature(absorbed_solar(1361, 0.3), 1))
    assert np.isclose(earth, 254.6, atol=0.1)

    fig, ax = plt.subplots()
    ax.plot(albedo, temperature, label="radiative balance, no atmosphere")
    ax.axhline(288, color="tab:red", ls="--", label="observed mean surface")
    ax.annotate("", xy=(0.3, 288), xytext=(0.3, earth), arrowprops={"arrowstyle": "<->"})
    ax.text(0.31, (288 + earth) / 2, f"greenhouse gap {288 - earth:.0f} K", va="center")
    ax.plot(0.3, earth, "ko")
    ax.set(xlabel="planetary albedo", ylabel="temperature [K]", title="The Earth is warmer than radiative balance allows")
    ax.legend(loc="lower left")

    plt.show()


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

   **Total running time of the script:** (0 minutes 0.092 seconds)


.. _sphx_glr_download_api_gallery_climate_plot_01_fourier_greenhouse.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_01_fourier_greenhouse.ipynb
        :alt: Launch JupyterLite
        :width: 150 px

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

      :download:`Download Jupyter notebook: plot_01_fourier_greenhouse.ipynb <plot_01_fourier_greenhouse.ipynb>`

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

      :download:`Download Python source code: plot_01_fourier_greenhouse.py <plot_01_fourier_greenhouse.py>`

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

      :download:`Download zipped: plot_01_fourier_greenhouse.zip <plot_01_fourier_greenhouse.zip>`


.. only:: html

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

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