divergence

metpy.calc.divergence(u, v, *, dx=None, dy=None, x_dim=-1, y_dim=-2, parallel_scale=None, meridional_scale=None, latitude=None, longitude=None, crs=None)

Calculate the horizontal divergence of a vector.

Parameters:

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

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

• 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. Keyword-only argument.

• 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. Keyword-only argument.

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

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

• parallel_scale (pint.Quantity, optional) – Parallel scale of map projection at data coordinate. Optional if xarray.DataArray with latitude/longitude coordinates and MetPy CRS used as input. Also optional if longitude, latitude, and crs are given. If otherwise omitted, calculation will be carried out on a Cartesian, rather than geospatial, grid. Keyword-only argument.

• meridional_scale (pint.Quantity, optional) – Meridional scale of map projection at data coordinate. Optional if xarray.DataArray with latitude/longitude coordinates and MetPy CRS used as input. Also optional if longitude, latitude, and crs are given. If otherwise omitted, calculation will be carried out on a Cartesian, rather than geospatial, grid. Keyword-only argument.

• latitude (pint.Quantity, optional) – Latitude of data. Optional if xarray.DataArray with latitude/longitude coordinates used as input. Also optional if parallel_scale and meridional_scale are given. If otherwise omitted, calculation will be carried out on a Cartesian, rather than geospatial, grid. Keyword-only argument.

• longitude (pint.Quantity, optional) – Longitude of data. Optional if xarray.DataArray with latitude/longitude coordinates used as input. Also optional if parallel_scale and meridional_scale are given. If otherwise omitted, calculation will be carried out on a Cartesian, rather than geospatial, grid. Keyword-only argument.

• crs (pyproj.crs.CRS, optional) – Coordinate Reference System of data. Optional if xarray.DataArray with MetPy CRS used as input. Also optional if parallel_scale and meridional_scale are given. If otherwise omitted, calculation will be carried out on a Cartesian, rather than geospatial, grid. Keyword-only argument.

Returns:

(…, M, N) xarray.DataArray or pint.Quantity – The horizontal divergence

See also

vorticity

Notes

This implements a numerical version of the typical equation of 2D divergence of a vector in Cartesian coordinates:

\[\nabla \cdot \vec{U} = \frac{\partial u}{\partial x} + \frac{\partial v}{\partial y}\]

Changed in version 1.0: Changed signature from (u, v, dx, dy)

Examples using metpy.calc.divergence

Divergence

Divergence