RETRIEVAL OF VERTICAL PROFILES OF OZONE FROM HIGH-RESOLUTION INFRAREDSOLAR SPECTRA AT RIKUBETSU, JAPAN

Vertical profiles of volume mixing ratios (VMRs) of O-3 were retrieved from high-resolution, infrared solar absorption spectra taken at Riku betsu, Japan (43.5 degrees N), by a ground-based Fourier transform inf rared spectrometer (FTIR). The VMR profile retrieval is based on an it erative inversion algorithm, which utilizes line-by-line, layer-by-lay er calculations. Two different microwindow regions (1146 and 1163 cm(- 1)) were used for the retrieval calculations. Eighty ozone vertical pr ofiles were retrieved from the two spectral regions from 40 spectra an d were compared with 17 ozonesonde measurements from a nearby station, Average differences between 18 and 34 km were less than +/-12% for bo th 1146 and 1163 cm(-1) retrievals. The standard deviation of the aver age differences between 18 and 34 km were less than 19% and 14% for re spective windows. Effects of several different factors on errors of pr ofile retrievals, such as initial guess, temperature profiles, and ins trument line shape functions, were evaluated by numerical simulation. The estimated errors were extremely consistent with the observed error s between 18 and 34 km, suggesting that the FTIR was optically well ad justed. In general, retrieval of the O-3 profile gives VMRs in an accu racy better than 40% at 14 km, improving to 10-15% between 18 and 30 k m, with precision of 30% and 20% for these altitude ranges, respective ly.