improver.uv_index module

Module for calculating the uv index using radiation flux in UV downward at surface and radiation flux in UV upward at the surface.

improver.uv_index.calculate_uv_index(uv_upward, uv_downward, scale_factor=3.6)[source]

A plugin to calculate the uv index using radiation flux in UV downward at surface, radiation flux UV upward at surface and a scaling factor. The scaling factor is configurable by the user.

Parameters

  • uv_upward (iris.cube.Cube) – A cube of the radiation flux in UV upward at surface. This is a UM diagnostic produced by the UM radiation scheme. This band covers 200-320 nm and uses six absorption coefficients for ozone and one Rayleigh scattering coefficient(W m-2)

  • uv_downward (iris.cube.Cube) – A cube of the radiation flux in UV downward at surface. This is a UM diagnostic produced by the UM radiation scheme see above or the paper referenced for more details.(W m-2)

  • scale_factor (float) – The uv scale factor. Default is 3.6. This factor has been empirically derived and should not be changed except if there are scientific reasons to do so. For more information see section 2.1.1 of the paper referenced below (no units)

Returns

A cube of the calculated UV index.

Return type

iris.cube.Cube

Raises

References

Turner, E.C, Manners, J. Morcette, C. J, O’Hagan, J. B, & Smedley, A.R.D. (2017): Toward a New UV Index Diagnostic in the Met Office’s Forecast Model. Journal of Advances in Modeling Earth Systems 9, 2654-2671.