.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "api/gallery/hydrology/plot_03_dalton_evaporation_law.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_hydrology_plot_03_dalton_evaporation_law.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_hydrology_plot_03_dalton_evaporation_law.py:


Dalton's evaporation law (1802)
===============================

John Dalton measured the water lost from heated vessels and found that the
rate of evaporation is proportional to the difference between the vapour
pressure at the temperature of the water and the vapour pressure already in
the air, and grows with the wind. Evaporation stops when the air is saturated
and turns into condensation when the air holds more vapour than the surface.

.. GENERATED FROM PYTHON SOURCE LINES 11-32



.. image-sg:: /api/gallery/hydrology/images/sphx_glr_plot_03_dalton_evaporation_law_001.png
   :alt: Dalton: evaporation follows the vapour-pressure deficit
   :srcset: /api/gallery/hydrology/images/sphx_glr_plot_03_dalton_evaporation_law_001.png
   :class: sphx-glr-single-img





.. code-block:: Python


    import matplotlib.pyplot as plt
    import numpy as np

    from earthsciencekit.atmosphere import saturation_vapor_pressure
    from earthsciencekit.hydrology import dalton_evaporation

    surface = saturation_vapor_pressure(293.15)  # water at 20 degC
    air = np.linspace(0, 1.2 * surface, 100)
    fig, ax = plt.subplots()
    for wind in (0.5, 2.0, 5.0):
        coefficient = 3.0e-8 * (1 + 0.54 * wind)  # kg/(m^2 s Pa), 0.26 (1 + 0.54 u) mm/day per hPa
        rate = dalton_evaporation(surface, air, coefficient) * 86400  # mm/day
        ax.plot(air / surface, rate, label=f"wind {wind:g} m/s")
    assert dalton_evaporation(surface, surface, 1e-9) == 0 and dalton_evaporation(surface, 1.1 * surface, 1e-9) < 0
    ax.axhline(0, color="0.5", lw=0.8)
    ax.set(xlabel="air vapour pressure / saturation at the water surface", ylabel="evaporation [mm/day]")
    ax.set_title("Dalton: evaporation follows the vapour-pressure deficit")
    ax.legend()

    plt.show()


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

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


.. _sphx_glr_download_api_gallery_hydrology_plot_03_dalton_evaporation_law.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/hydrology/plot_03_dalton_evaporation_law.ipynb
        :alt: Launch JupyterLite
        :width: 150 px

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

      :download:`Download Jupyter notebook: plot_03_dalton_evaporation_law.ipynb <plot_03_dalton_evaporation_law.ipynb>`

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

      :download:`Download Python source code: plot_03_dalton_evaporation_law.py <plot_03_dalton_evaporation_law.py>`

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

      :download:`Download zipped: plot_03_dalton_evaporation_law.zip <plot_03_dalton_evaporation_law.zip>`


.. only:: html

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

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