Where
X = total amount of ozone expressed in Dobson Units (1 DU = 10-5 m pure ozone at STP),
or in atmo-cm;
N = L0 − L = log(I 0 / I'0) − log(I / I')
I0 and I0' = intensities outside the atmosphere of solar radiation at the short and long
wavelengths, respectively, of the wavelength pair;
I and I' = measured intensities at the ground of solar radiation at the short and long
wavelengths, respectively;
β and β’ = Rayleigh scattering coefficients of air at the short and long wavelengths,
respectively;
m = ratio of the actual and vertical paths of solar radiation through the atmosphere, taking
into account refraction and the earth's curvature: airmass;
3
p = observed station pressure;
p0 = mean sea level pressure;
δ and δ' = scattering coefficients of aerosol particles at the short and long wavelengths,
respectively;
SZA = solar zenith angle - angular zenith distance of the sun;
ά and ά' = absorption coefficients of ozone at the short and long wavelengths, respectively;
μ = ratio of the actual and vertical paths of solar radiation through the ozone layer, the
mean height of the ozone layer being 22 km if not approximated by latitude of the
station