storm_relative_helicity¶
- metpy.calc.storm_relative_helicity(height, u, v, depth, *, bottom=None, storm_u=None, storm_v=None)¶
Calculate storm relative helicity.
Calculates storm relative helicity following [Markowski2010] pg.230-231
\[\int\limits_0^d (\bar v - c) \cdot \bar\omega_{h} \,dz\]This is applied to the data from a hodograph with the following summation:
\[\sum_{n = 1}^{N-1} [(u_{n+1} - c_{x})(v_{n} - c_{y}) - (u_{n} - c_{x})(v_{n+1} - c_{y})]\]- Parameters
u (array-like) – U component winds
v (array-like) – V component winds
height (array-like) – Atmospheric height, will be converted to AGL
depth (number) – Depth of the layer
bottom (number) – Height of layer bottom AGL (default is surface)
storm_u (number) – U component of storm motion (default is 0 m/s)
storm_v (number) – V component of storm motion (default is 0 m/s)
- Returns
pint.Quantity
– Positive storm-relative helicitypint.Quantity
– Negative storm-relative helicitypint.Quantity
– Total storm-relative helicity
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 toheight
and convertedbottom
,storm_u
, andstorm_v
parameters to keyword-only arguments