Observations of OH airglow from ground, aircraft, and satellite: investigation of wave-like structures before a minor stratospheric warming

Abstract

Abstract. In January and February 2016, the OH airglow camera system FAIM (Fast Airglow Imager) measured during six flights on board the research aircraft FALCON in northern Scandinavia. Flight 1 (14 January 2016) covering the same ground track in several flight legs and flight 5 (28 January 2016) along the shoreline of Norway are discussed in detail in this study. The images of the OH airglow intensity are analysed with a two-dimensional FFT regarding horizontal periodic structures between 3 and 26 km horizontal wavelength and their direction of propagation. Two ground-based spectrometers (GRIPS, Ground-based Infrared P-branch Spectrometer) provided OH airglow temperatures. One was placed at ALOMAR, Northern Norway (Arctic Lidar Observatory for Middle Atmosphere Research; 69.28∘ N, 16.01∘ E) and the other one at Kiruna, northern Sweden (67.86∘ N, 20.24∘ E). Especially during the last third of January 2016, the weather conditions at Kiruna were good enough for the computation of nightly means of gravity wave potential energy density. Coincident TIMED-SABER (Thermosphere Ionosphere Mesosphere Energetics Dynamics–Sounding of the Atmosphere using Broadband Emission Radiometry) measurements complete the data set. They allow for the derivation of information about the Brunt–Väisälä frequency and about the height of the OH airglow layer as well as its thickness. The data are analysed with respect to the temporal and spatial evolution of mesopause gravity wave activity just before a minor stratospheric warming at the end of January 2016. Wave events with periods longer (shorter) than 60 min might mainly be generated in the troposphere (at or above the height of the stratospheric jet). Special emphasis is placed on small-scale signatures, i.e. on ripples, which may be signatures of local instability and which may be related to a step in a wave-breaking process. The most mountainous regions are characterized by the highest occurrence rate of wave-like structures in both flights.

Intra-annual variations of spectrally resolved gravity wave activity in the upper mesosphere/lower thermosphere (UMLT) region

“…Vadas and Fritts, 2002;Vadas et al, 2003;Franke and Robinson, 1999). Recent observations show that secondary gravity waves are often generated in the stratosphere and propagate upward into the UMLT (Chen et al, 2013(Chen et al, , 2016Yamashita et al, 2009;Zhao et al, 2017) where they would be observable, e.g. with OH* spectrometers.…”

Gravity wave instability structures and turbulence from more than one and a half years of OH* airglow imager observations in Slovenia

“…These include spectroscopic measurements of strong emission lines and the analysis of temperature time series derived from these (Hines & Tarasick, 1987;Mulligan et al, 1995;Bittner et al, 2000;Reisin & Scheer, 2001;Espy & Stegman, 2002;Espy et al, 2003;French & Burns, 2004;Schmidt et al, 2013, Wachter et al, 2015Silber et al, 2016, 2017a, but also two-dimensional imaging in the short-wave infrared (SWIR) range (see e.g. Peterson & Kieffaber, 1973;Hecht et al, 1997;Taylor, 1997;Moreels et al, 2008;Li et al, 2011;Pautet et al, 2014;Hannawald et al, 2016Hannawald et al, , 2019Sedlak et al, 2016;Wüst et al, 2019 and many more).…”

A Comparison of Fabry–Perot Interferometer and Meteor Radar Wind Measurements Near the Polar Mesopause Region

“…The height of hydroxyl (OH) emission layer is assumed to be 87 km with a full width at half maximum (FWHM) of about 8 km (Baker & Stair, 1988) and the height of OI‐green line emission layer is widely known to be 97 km with a FWHM of 7 km (Yee & Abreu, 1987). However, the true heights of airglow emission layers are not fixed at all but vary not only with times of day and seasons (Gao et al., 2010; Smith et al., 2010) but also with locations (Liu et al., 2008; Wüst et al., 2019). In particular, the temporal variations of the emission peak height can have a significant impact on the characteristics of the physical parameters of the MLT region derived from the ground‐based observations of the airglow layers.…”