演講資訊

摘要：

Airglow images of OH(6,2) and O( 1 S) emissions by a CCD all-sky imager at the Andes Lidar Observatory (ALO) from September 2011 to April 2018 have been analyzed. An unusual intensity pattern showing an O( 1 S) nightglow intensity enhancement concurrent with an OH(6,2) nightglow intensity weakening has been identified. About 142 nights showing a remarkable biannual occurrence rate with maxima around the equinoxes. The monthly averaged data was fitted with a semi-diurnal tide. The largest amplitudes were found for the months of April and August-October in the OH(6,2) data and April and September in the O( 1 S) data. SABER’s atomic oxygen at the O( 1 S) peak height is 1.3-2.5 times higher during the nights that displayed the unusual intensity pattern. A temperature increase at 96 km and a temperature decrease at 87 km were also seen during those nights. We used two airglow models, OHCD and MACD, with temperature from Na Lidar and atomic oxygen from SABER to investigate the effect of a long-period (12-h) wave on the OH(6,2) and O( 1 S) airglow intensities. The simulation results show good agreement with the observations replicating the unusual intensity pattern. Our study indicates that a combination of the factors like tidal amplitudes, vertical wavelength, temperature, and greater amount of [O] can produce the unusual intensity pattern observed in the airglow data