APPLICATION OF A RADIOMETRIC CALIBRATION METHOD TO LUNAR FOURIER-TRANSFORM IR-SPECTRA BY USING A LIQUID-NITROGEN-COOLED HIGH-EMISSIVITY BLACKBODY

Since winter 1994/1995 the Moon has been used in addition ta the Sun a s an IR source of radiation to measure atmospheric absorption spectra with a Bruker IR Fourier transform spectrometer IFS 120M located near Kiruna, Sweden. A two-point radiometric calibration method with blackb ody references was applied to lunar spectra in the long-wave detector channel to improve the accuracy of evaluation of the column amounts of different atmospheric trace gases. A new liquid-nitrogen-cooled high- emissivity blackbody without an entrance window is described that is u sed far this calibration method. (C) 1997 Optical Society of America.