Universal Thermal Climate Index (UTCI)
======================================
The universal thermal climate index (UTCI), is a bioclimatological model of an average human body’s response
to different thermal conditions, where the subject is
not acclimatised to the climate and is outdoors, doing minimal work.

More Information: https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/gdj3.102


How To Use
----------------

You will need 2m temperature and mean radiant temperature in Kelvin,
relative humidity (calculated as shown below,using 2m dew point temperature in Kelvin) and 10 meter height wind speed in m/s.
Please use with numpy arrays.

It returns the universal thermal climate index in Celsius. 

.. code-block:: python

    rh_pc = tfc.calculate_relative_humidity_percent(self.t2m, self.td)
    ehPa = tfc.calculate_saturation_vapour_pressure(self.t2m) * rh_pc / 100.0
    utci = calculate_utci(2m_temperature,mean_radiant_temperature, 10m_wind_speed,
    2m_dew_point_temperature=None, ehPa=None)


Interpret the Output
-------------------------

.. csv-table:: UTCI Thresholds
    :file: utcithresholds.csv
    :header-rows: 1
    :class: longtable
    :widths: 1 1