vertical_velocity#

metpy.calc.vertical_velocity(omega, pressure, temperature, mixing_ratio=0)[source]#

Calculate w from omega assuming hydrostatic conditions.

This function converts vertical velocity with respect to pressure $$\left(\omega = \frac{Dp}{Dt}\right)$$ to that with respect to height $$\left(w = \frac{Dz}{Dt}\right)$$ assuming hydrostatic conditions on the synoptic scale. By Equation 7.33 in [Hobbs2006],

$\omega \simeq -\rho g w$

so that

$w \simeq \frac{- \omega}{\rho g}$

Density ($$\rho$$) is calculated using the density() function, from the given pressure and temperature. If mixing_ratio is given, the virtual temperature correction is used, otherwise, dry air is assumed.

Parameters:
Returns:

pint.Quantity – Vertical velocity in terms of height (in meters / second)

Examples

>>> from metpy.calc import vertical_velocity
>>> from metpy.units import units
>>> vertical_velocity(-15 * units('Pa/s'), 700 * units.hPa, 5 * units.degC)
<Quantity(1.74463814, 'meter / second')>