frontogenesis

metpy.calc.frontogenesis(potential_temperature, u, v, dx=None, dy=None, x_dim=- 1, y_dim=- 2)[source]

Calculate the 2D kinematic frontogenesis of a temperature field.

The implementation is a form of the Petterssen Frontogenesis and uses the formula outlined in [Bluestein1993] pg.248-253

\[F=\frac{1}{2}\left|\nabla \theta\right|[D cos(2\beta)-\delta]\]

  • \(F\) is 2D kinematic frontogenesis

  • \(\theta\) is potential temperature

  • \(D\) is the total deformation

  • \(\beta\) is the angle between the axis of dilitation and the isentropes

  • \(\delta\) is the divergence

Parameters

  • potential_temperature ((…, M, N) xarray.DataArray or pint.Quantity) – Potential temperature

  • u ((…, M, N) xarray.DataArray or pint.Quantity) – x component of the wind

  • v ((…, M, N) xarray.DataArray or pint.Quantity) – y component of the wind

  • dx (pint.Quantity, optional) – The grid spacing(s) in the x-direction. If an array, there should be one item less than the size of u along the applicable axis. Optional if xarray.DataArray with latitude/longitude coordinates used as input.

  • dy (pint.Quantity, optional) – The grid spacing(s) in the y-direction. If an array, there should be one item less than the size of u along the applicable axis. Optional if xarray.DataArray with latitude/longitude coordinates used as input.

  • x_dim (int, optional) – Axis number of x dimension. Defaults to -1 (implying […, Y, X] order). Automatically parsed from input if using xarray.DataArray.

  • y_dim (int, optional) – Axis number of y dimension. Defaults to -2 (implying […, Y, X] order). Automatically parsed from input if using xarray.DataArray.

Returns

(…, M, N) xarray.DataArray or pint.Quantity – 2D Frontogenesis in [temperature units]/m/s

Notes

Conversion factor to go from [temperature units]/m/s to [temperature units/100km/3h] \(1.08e4*1.e5\)

Changed in version 1.0: Changed signature from (thta, u, v, dx, dy, dim_order='yx')

exner_function geostrophic_wind