Meteorological Research Institute
Upper Atmosphere Research Laboratory, Tohoku University
Meteorological Research Institute
National Institute of Polar Research
National Institute of Polar Research
Upper Atmosphere Research Laboratory, Tohoku University
Geophysics Research Laboratory, University of Tokyo
JEOL Ltd.
JEOL Ltd.
As part of the Japanese Antarctic Middle Atmosphere Program (Antarctic MAP), columnar amounts of atmospheric minor constituents such as N_2O, CH_4,CFCl_3,CF_2Cl_2 and HNO_3 were determined from measurements of infrared solar spectra for the period 24 March 1983-29 December 1984 at Syowa Station, Antarctica (69°00′S, 39°35′E). A Fourier-transform-infrared spectrometer was used to measure the solar spectra. The highest apodized resolution of the spectrometer is 0.1(cm)^<-1> (full width at half-maximum), but the resolution of 0.8(cm)^<-1> was adopted in routine operation because of an economy of data processing time and of better signal to noise (S/N) ratio. The accuracy of measurements is estimated from S/N ratios of the obtained spectra; typical errors of measured abundances were ±40,±2 and ±6% for CFCl_3 (at 850(cm)^<-1>), N_2O (at 2576(cm)^<-1>) and CH_4 (at 6004(cm)^<-1>), respectively. A MCT detector (cooled at 77 K) is desirable to attain higher resolutions (∿0.1(cm)^<-1>) and larger S/N ratios.