ACCURACY OF TOTAL OZONE COLUMN AMOUNTS OBSERVED WITH SOLAR INFRARED-SPECTROSCOPY

Total ozone column amounts were observed at Rikubetsu (43.5 degrees N, 143.8 degrees E), Japan on 90 days between May Is, 1995 and April 26, 1996 with a high-resolution infrared (In) Fourier transform spectrome ter and compared with Dobson spectrometer measurements. The sensitivit ies of the analysis for IR solar absorption spectra to initial profile s were examined using two kinds of initial profiles for ozone and temp erature, namely monthly and yearly averages. IR/Dobson mean column rat ios in the two cases were 1.02 and 1.03 and the standard deviation of the ratios were 3.7 and 4.1%, which correspond to 14 and 16 Dobson Uni ts. The standard deviations are smaller than or comparable to the ampl itudes of the day-to-day total ozone column variations indicating that day-to-day variations can be detected using monthly or yearly average d profiles. However, significant solar zenith angle (SZA) dependences were observed in the columns derived using yearly averaged profiles. T he SZA dependence was most significant ill January and February when t he ozone amount, in the lower stratosphere was largest. The SZA depend ence is considered to be caused by the difference between initial and actual ozone profiles.