.. _divwind_icon:


divwind
===============================================

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        .. image:: /_static/DIVROT.png
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		Computes the divergent wind from spectral (shperical harmonics) divergence GRIB fields.


		.. note:: This function performs the same task as the **Rotational or Divergent Wind** icon in Metview’s :ref:`user interface <user_interface>`. It accepts its parameters as keyword arguments, described below.


.. py:function:: divwind(**kwargs)
  
    Computes the divergent wind from spectral (spherical harmonics) divergence GRIB fields.


    :param data: Specifies the divergence GRIB fields. Must be spectral (spherical harmonics) data.
    :type data: :class:`Fieldset`

    :param divergence_param: Specifies the ecCodes paramId that identifies the divergence in ``data``. *New in Metview version 5.13.0.*
    :type divergence_param: number, default: 155

    :param truncation: Specifies the triangular truncation to be applied to the spherical harmonics input data prior to conversion to lat/lon.
    :type truncation: number, default: 216

    :param smoothing: Specifies whether to apply spatial smoothing to the spherical harmonics prior to transformation to grid points. This operation is performed after the truncation specified in ``truncation``. The smoothing filter is of the form: 
		
		.. math::
		  
		  exp^{(-\frac {n(n+1)}{fltc(fltc+1)})^{mfltexp}}
		
		where:
		
		* n: is the wavenumber
		* fltc, mfltexp: see below
		
		This is roughly equivalent to a :math:`\nabla^{2 \times mfltexp}` operator in grid point space.
    :type smoothing: {"yes", "no"}, default: "no"

    :param fltc: Specifies the value of the parameter fltc to be used in the smoothing filter. Only available if ``smoothing`` set to "yes".
    :type fltc: number, default: 19.4

    :param mfltexp: Specifies the value of the parameter ``mfltexp`` to be used in the smoothing filter. Only available if ``smoothing`` is set to "yes". The default value is 2, roughly equivalent to a  :math:`\nabla^{4}` operator in grid point space.
    :type mfltexp: number, default: 2

    :rtype: :class:`Fieldset`

.. mv-minigallery:: divwind