precipitable_water#

metpy.calc.precipitable_water(pressure, dewpoint, *, bottom=None, top=None)#

Calculate precipitable water through the depth of a sounding.

Formula used is:

\[-\frac{1}{\rho_l g} \int\limits_{p_\text{bottom}}^{p_\text{top}} r dp\]

from [Salby1996], p. 28

Parameters

  • pressure (pint.Quantity) – Atmospheric pressure profile

  • dewpoint (pint.Quantity) – Atmospheric dewpoint profile

  • bottom (pint.Quantity, optional) – Bottom of the layer, specified in pressure. Defaults to None (highest pressure).

  • top (pint.Quantity, optional) – Top of the layer, specified in pressure. Defaults to None (lowest pressure).

Returns

pint.Quantity – Precipitable water in the layer

Examples

>>> pressure = np.array([1000, 950, 900]) * units.hPa
>>> dewpoint = np.array([20, 15, 10]) * units.degC
>>> pw = precipitable_water(pressure, dewpoint)

Notes

Only functions on 1D profiles (not higher-dimension vertical cross sections or grids).

Changed in version 1.0: Signature changed from (dewpt, pressure, bottom=None, top=None)

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