Estimation of the necessary contrast of optical interference filters for ozone measurements in the atmosphere

The requirements imposed on the spectral characteristics of optical filters for portable optical ozonometers are analyzed; when satisfied, they make it possible to determine the total atmospheric ozone to an accuracy no lower than the accuracy achieved by complex spectral slit instruments. Considered is the dependence of the calculated ozone absorption coefficients on the spectral characteristic of the filters and total ozone for the nonmonochromatic radiation measured with two optical filters. Estimates of the role of contrast and permissible values of the background transmittance of filters in the range of 294.8–400 nm are presented. With these estimates taken into account, it is recommended in two-filter ozonometers to use interference filters with a transmission maxima at 305.5–307 and 326–330 nm with a spectral width of their bands at half of the height of the maximum transmission of 2–5 nm.