**Outdoor Spectra**

PAR summationPAR summation

Spectral data can be integrated over the 400 to 700 nm waveband to compute the Photosynthetically Active Radiation (PAR) using the formula: |

1/(B*h*c) * _{400 }∫^{ 700} λ * E(λ) dλ, where |

B = Avogadro's number = 6.0221413e17 photons/µmole |

h = Planck's constant = 6.62606957e-34 watt s^{2} |

c = speed of light = 299792458e9 nm/s |

λ = Spectroradiometer wavelength (nm) |

E(λ) = Measured Spectral Irradiance at λ (W/m^{2}/nm) |

[MID

*C*]