NO. 3 MEASUREMENT OF OZONE — WULF AND ZIMMERMAN 5 



density are the ozone-absorption term containing the unknown amount 

 of ozone, the scattering term in the — 2 power of the wavelength with 

 unknown coefficient, and the unknown wavelength-independent scat- 

 tering ^. The entire expression at some one wavelength, A„, may thus 

 be written 



-l0gTn = anX + l3(lXn^-iyK-* + B-K-- + ^ (l) 



where Tn is the measured transmission coefficient at wavelength A„. 

 an is the laboratory-measured absorption coefficient of ozone at 



this wavelength, expressed in reciprocal centimeters of the 



pure gas at standard conditions. 

 X is the amount of ozone (to be determined) expressed in 



centimeters of the pure gas at standard conditions. 

 /3 is the coefficient of the Rayleigh-scattering term. 

 fin is the index of refraction of air at standard conditions at 



wavelength A„. 

 8 is the coefficient (to be determined) of the intermediate 



scattering term. 

 ^ is the wavelength-independent scattering (to be determined). 



In principle, values of the transmission coefficient at three wave- 

 lengths in the spectral region of ozone absorption suffice to determine 

 the three unknowns, x, 8, and ^. However, to make adequate use of 

 the available data it is of course preferable to use the observations at 

 a number of wavelengths, combining the several independent equations 

 so obtained into three equations in the final solution for the three 

 unknowns. 



Transmission coefficients are determined in the solar-constant work 

 at a considerable number of places in the spectrum from the infrared 

 into the ultraviolet. From these, seven places have been chosen in the 

 present work for the determination of ozone, namely Places 19 at 

 0.722 fi, 20 at 0.686 [x, 22 at 0.614 fi, 24 at 0.570 fi, 26 at 0.532 /a, 28 

 at 0.499 /^' ^"d 30 at 0.470 fi. 



This method of ozone determination assumes that the ozone value 

 does not change appreciably over the spectrobolometric observations 

 of the sun at the several zenith angles from which the transmission 

 coefficients are determined. 



Transferring the Rayleigh-scattering term to the left-hand side of 

 the equation, one has a series of n equations, in the present work 

 seven, of the form 



(2) 

 - log T30 - i8 (/X30' - I ) 'Aso"" = a3o • ^ + A30-' • 8 + ^ 



