critical_angle

metpy.calc.critical_angle(pressure, u, v, height, u_storm, v_storm)

Calculate the critical angle.

The critical angle is the angle between the 10m storm-relative inflow vector and the 10m-500m shear vector. A critical angle near 90 degrees indicates that a storm in this environment on the indicated storm motion vector is likely ingesting purely streamwise vorticity into its updraft, and [Esterheld2008] showed that significantly tornadic supercells tend to occur in environments with critical angles near 90 degrees.

Parameters:

• pressure (pint.Quantity) – Pressures from sounding

• u (pint.Quantity) – U-component of sounding winds

• v (pint.Quantity) – V-component of sounding winds

• height (pint.Quantity) – Heights from sounding

• u_storm (pint.Quantity) – U-component of storm motion

• v_storm (pint.Quantity) – V-component of storm motion

Returns:

pint.Quantity – Critical angle in degrees

Examples

>>> from metpy.calc import critical_angle, wind_components
>>> from metpy.units import units
>>> p = [1000, 925, 850, 700, 500, 400] * units.hPa
>>> h = [250, 700, 1500, 3100, 5720, 7120] * units.meters
>>> wdir = [165, 180, 190, 210, 220, 250] * units.degree
>>> sped = [5, 15, 20, 30, 50, 60] * units.knots
>>> u, v = wind_components(sped, wdir)
>>> critical_angle(p, u, v, h, 7 * units.knots, 7 * units.knots)
<Quantity(67.0942521, 'degree')>

Notes

Only functions on 1D profiles (not higher-dimension vertical cross sections or grids). Since this function returns scalar values when given a profile, this will return Pint Quantities even when given xarray DataArray profiles.

Changed in version 1.0: Renamed heights parameter to height

Examples using metpy.calc.critical_angle

Sounding Calculation Examples

Sounding Calculation Examples