An estimate of the effect of El Chichon aerosol on SBUV profiling for summer 1982

A case study of the error introduced by the presence of high stratospheric aerosol concentrations into ozone mixing ratio profiles inferred from “simulated measurements” of solar backscattered ultraviolet radiation (SBUV) has been made for the northern tropics (for average stratospheric conditions) during the summer of 1982, a period of unusually high stratospheric turbidity due to the eruptions of El Chichon in the spring. The spectral radiance reflected from the earth's atmosphere was computed for seven wavelengths used in ozone profile recovery by the SBUV instrument. These “simulated measurements,” based on the average July 1979 ozone profile for the 10°–20°N latitude belt and published aerosol optical data, were inverted by a procedure that does not take aerosol scattering or multiple scattering into consideration for the purpose of investigating the accuracy of the aerosol‐free approximation. Comparison is made of the “actual” ozone mixing ratio profile and the inversion solution profiles for aerosol‐free and volcanically perturbed conditions. It is found that the presence of El Chichon aerosol could cause an error in the neighborhood of −25% in the inferred cumulative ozone between zero and 100 mbar if aerosol effects are neglected.