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Mean Radiant Temperature

The Mean Radiant Temperature (MRT) is defined as that uniform temperature of a fictive black-body radiation enclosure (emission coefficient ε = 1) which would result in the same net radiation energy exchange with the subject as the actual, more complex radiation environment. MRT is a key component of calculating indices such as the Wet Bulb Globe Temperature and Universal Thermal Climate Index.

More information: Di Napoli, C., Hogan, R.J. & Pappenberger, F. Mean radiant temperature from global-scale numerical weather prediction models. Int J Biometeorol 64, 1233–1245 (2020). https://doi.org/10.1007/s00484-020-01900-5

How to use

There are two different methods to calculate MRT in thermofeel.

Mean Radiant Temperature

It requires the following variables:

  • ssrd is the surface solar radiation downwards
  • ssr is the surface net solar radiation
  • dsrp is the direct radiation from the Sun
  • strd is the surface thermal radiation downwards
  • fdir is the total sky direct solar radiation at surface
  • strr is the surface net thermal radiation
  • cossza is the cosine of the solar zenith angle

All the radiation variables are in W m⁻² and the cosine of the solar zenith angle is dimensionless. Please use NumPy arrays.

It returns the mean radiant temperature in Kelvin.

calculate_mean_radiant_temperature(ssrd, ssr, dsrp, strd, fdir, strr, cossza)

Mean Radiant Temperature from Globe Temperature

2 m air temperature and 2 m globe temperature are expressed in Kelvin and 10 m wind speed in metres per second. Please use NumPy arrays.

It returns the mean radiant temperature in Kelvin.

calculate_mrt_from_bgt(2m_temperature, globe_temperature, 10m_wind_speed)