O2 and OH Night Airglow Emission Derived from GOMOS-Envisat Instrument

Abstract

lobal Ozone Monitoring by Occultation of Stars (GOMOS) was an instrument dedicated to the study of atmospheric chemistry based on the principle of stellar occultation. The signals delivered by the IR spectrometer coupled with two CCD detectors, initially used for absorption measurements, were analyzed in order to observe the night airglow resulting from O2 and OH emissions at 761.9 and 930 nm, respectively. The method to retrieve those emissions is described as well as the error analysis. The results of this first attempt are presented and discussed with respect to instrument characteristics, earth coverage, altitude resolution, and the ability of GOMOS data to contribute to night airglow investigations. Mean limb intensities are equal to 28.9 and 7.7 MR for O2 at 760 nm and OH at 930 nm, respectively. Individual O2 emissions are retrieved with an accuracy better than 15%, while the OH emission, which provides smaller intensities, is retrieved with an accuracy of 10% for the monthly average.