frontogenesis

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

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 dilatation 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

To convert from [temperature units]/m/s to [temperature units]/100km/3h, multiply by \(1.08e9\)

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

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