Summer-time nocturnal wave characteristics in mesospheric OH and O2 airglow emissions

Abstract

Abstract The mesospheric temperature mapper (MTM) measurements on mesospheric OH (6, 2) and O2 (0, 1) band emissions from Maui, Hawaii during July, 2002 show significant day-to-day variability. The nocturnal variability reveals prominent wave signatures with a periodicity ranging from 6 to 13 h. For better characterization of the nocturnal wave in the data, a Krassovsky’s η (∼|η|e iφ) analysis was carried out. Deduced Krassovsky parameters show significant variability, with ranges of |η| ∼ 1.7–3.9 for the OH data and ∼4.3–13 for the O2 data. The phase values of Krassovsky parameters exhibit larger variability, with variations from approximately −91° to +23° for the OH data and −45° to −10° for the O2 data. Comparison of these values with existing observations and models show large deviations from model values and relatively better agreements with the observed values reported by other investigators. The deduced vertical wavelength from |η| and φ indicates that our data is mostly dominated by upward propagating waves with occasional high values ≥100 km, implying possible evanescent waves.