Knowledge Bank

Among the various techniques used to measure the ozone concentration profile in the atmosphere, optical remote sensing techniques are widely used. They cover large parts of the electromagnetic range (MW,IR,UV) and, as far as the infrared domain is concerned, the $10\mu m$ region is of special interest since it corresponds to an atmospheric window and to the strongest absorption of this molecule. Therefore, this region has been the subject of numerous spectroscopic $studies(abcd$ and refs. herein) in order to generate the best spectral parameters for atmospheric retrievals. In these studies two main methods are used to determine the $O3$ concentration in the cell: measurement and monitoring of the pressure or use, as a reference standard, of the UV absorption at 254 nm. The goal of this talk is to present a comparison of the line intensity data recently obtained using either pressure $measurementsabc$ or the UV $absorptiond$. Whereas the results obtained in $refsabc$ agree to within 1.6%, it appears that the results of $refd$ are consistently about 4% higher. However it should be noted that in $ref.b$ the two methods (pressure measurements and UV absorption) were used to derive the $O3$ concentrations in the cell and that the results are in excellent agreement. A new calculation based on the experimental values of $refs.abc$ has been performed and compared with the HITRAN values showing that these latter values are also about 4% higher.