precipitable_water¶

metpy.calc.precipitable_water(dewpt, pressure, bottom=None, top=None)[source]¶

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

dewpt (pint.Quantity) – Atmospheric dewpoint profile
pressure (pint.Quantity) – Atmospheric pressure profile
bottom (pint.Quantity, optional) – Bottom of the layer, specified in pressure. Defaults to None (highest pressure).
top (pint.Quantity, optional) – The top of the layer, specified in pressure. Defaults to None (lowest pressure).

Returns

pint.Quantity – The 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(dewpoint, pressure)