.. py:function:: virtual_temperature(t, q)
*New in Metview version 5.13.0*.
Computes the virtual temperature from the given temperature (``t``) and specific humidity (``q``).
:param t: temperature (K)
:type t: number, ndarray or :class:`Fieldset`
:param q: specific humidity (kg/kg)
:type q: number, ndarray or :class:`Fieldset`
:rtype: same type as ``t`` or None
The result is the virtual temperature in K units. On error None is returned.
When the result is a :class:`Fieldset` the ecCodes **paramId** in the output is set to 300012 (=virtual temperature).
The computation is based on the following formula:
.. math::
T_{v} = T (1 + \frac{1 - \epsilon}{\epsilon} q)
where
* T is the temperature
* q is the specific humidity
* :math:`\epsilon = \frac{R_{dry}}{R_{vapour}} = 0.621981`
.. mv-minigallery:: virtual_temperature