Mesospheric temperatures from observations of the hydroxyl (6?2) emission above Davis, Antarctica: A comparison of rotational and Doppler measurements

• Main Authors: Innis, J. L., Phillips, F. A., Burns, G. B., Greet, P. A., French, W. J. R., Dyson, P. L.
• Other Authors: Australian Antarctic Division (AAD), Australian Government, Department of the Environment and Energy, Department of Physics, La Trobe University Melbourne
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2001
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Austral; Davis Station; Davis-Station; Antarc*; Antarctica
• Online Access: https://hal.science/hal-00316777; https://hal.science/hal-00316777/document; https://hal.science/hal-00316777/file/angeo-19-359-2001.pdf

International audience We present observations of the hydroxyl (6?2) airglow lines from ~ 87 km altitude obtained at Davis station, Antarctica, in the austral winter of 1999. Nine nights of observations were made of the P-branch near ?840 nm with a Czerny-Turner scanning spectrometer (CTS); at the same time, high-resolution Fabry-Perot Spectrometer (FPS) spectra were collected of the Q 1 (1) doublet at ?834 nm. Rotational temperatures were determined from the CTS observations, while Doppler temperatures were derived from the line-widths of the FPS Q 1 (1) spectra. Absolute temperatures determined by these methods are uncertain by ~ 2 and ~ 20 K, respectively. For the comparison we set the value of the reflective finesse of the FPS at ?834 nm so the mean FPS temperature from one night of simultaneous data was equal to that from the CTS, and then looked at the measured variations in each data set for the other eight nights. Both instruments show the upper mesosphere temperature to vary in a similar manner to within the observational errors of the measurements, implying an equivalence of the rotational and Doppler temperatures. We believe that this is the first published simultaneous, same-site, comparison of rotational and Doppler temperatures from the OH emission. Key words. Atmospheric composition and structure (airglow and aurora; pressure density and temperature; instruments and techniques)