First OH Airglow Observation of Mesospheric Gravity Waves Over European Russia Region

Abstract

For the first time, we perform a study of mesospheric gravity waves (GWs) for four different seasons of 1 year in the latitudinal band from 45°N to 75°N using an OH all‐sky airglow imager over Kazan (55.8°N, 49.2°E), Russia, during the period of August 2015 to July 2016. Our observational study fills a huge airglow imaging observation gap in Europe and Russia region. In total, 125 GW events and 28 ripple events were determined by OH airglow images in 98 clear nights. The observed GWs showed a strong preference of propagation toward northeast in all seasons, which was significantly different from airglow imager observations at other latitudes that the propagation directions were seasonal dependent. The middle atmosphere wind field is used to explain the lack of low phase speed GWs since these GWs were falling into the blocking region due to the filtering effects. Deep tropospheric convections derived from the European Centre for Medium‐Range Weather Forecasts reanalysis data are determined near Caucasus Mountains region, which suggests that the convections are the dominant source of the GWs in spring, summer, and autumn seasons. This finding extends our knowledge that convection might also be an important source of GWs in the higher latitudes. In winter the generation mechanism of the GWs are considered to be jet stream systems. In addition, the occurrence frequency of ripple is much lower than other stations. This study provides some constraints on the range of GW parameters in GW parameterization in general circulation models in Europe and Russia region.

A novel infrared imager for studies of hydroxyl and oxygen nightglow emissions in the mesopause above northern Scandinavia

“…noaa.gov/ccgg/trends_ch4/, last access: 27 February 2024), which may have caused the observed long-term trend in water vapor in the mesopause. Lübken et al (2018) have obtained a summer mesopause cooling of ∼ 1.2 K per decade for the period of 1960-2008 based on Leibniz Institute Middle Atmosphere (LIMA) and Mesospheric Ice Microphysics And tranSport (MIMAS) model simulations which included long-term evolutions of the minor atmospheric species CO 2 , CH 4 , H 2 O and O 3 . Thus, the long-term temperature trend in the middle atmosphere is a complex function of several atmospheric components.…”

“…More than 50 sites conducting spectroscopic and imaging airglow observations are presented at the Network for the Detection of Mesospheric Change (NDMC), which is a global program investigating climate change signals in the mesopause region (https://ndmc.dlr.de/, last access: 27 February 2024). Li et al (2018) have summarized a global distribution of all-sky airglow imager sites (see Table 1 in their paper and references therein). Some of the OH spectrographs and imaging instruments have a narrow field of view of 30°or less, such as the Ground-based Infrared P-branch Spectrometer instrument (GRIPS 6) in Oberpfaffenhofen, Germany (Schmidt et al, 2013); the Aerospace Nightglow Imager 2 (ANI2) in the Andes, Chile (Hecht et al, 2023); and the spectral airglow temperature imager (SATI) in Resolute Bay, Canada (Wiens et al, 1997).…”

“…Some of the OH spectrographs and imaging instruments have a narrow field of view of 30°or less, such as the Ground-based Infrared P-branch Spectrometer instrument (GRIPS 6) in Oberpfaffenhofen, Germany (Schmidt et al, 2013); the Aerospace Nightglow Imager 2 (ANI2) in the Andes, Chile (Hecht et al, 2023); and the spectral airglow temperature imager (SATI) in Resolute Bay, Canada (Wiens et al, 1997). A number of OH imaging instruments measure OH emissions in relative units without mesopause temperature derivations, such as the ANI2; the OH all-sky airglow imager in Kazan, Russia (Li et al, 2018); and the Fast Airglow IMager (FAIM) in Oberpfaffenhofen, Germany (Hannawald et al, 2016). Some of the OH imagers register OH emissions (including temperature derivations) without capturing infrared emissions coming from the O 2 layer, such as the Advanced Mesospheric Temperature Mapper (AMTM) at the South Pole (Pautet et al, 2014) and the Near InfraRed Aurora Camera (NIRAC) in Svalbard, Norway (Nishiyama et al, 2024).…”

Retrieval of intrinsic mesospheric gravity wave parameters using lidar and airglow temperature and meteor radar wind data

“…The impact of atmospheric gravity waves (GWs) on the energy and momentum budget, especially in the uppermesosphere, lower-thermosphere (MLT) region has long been recognized (Lindzen, 1981;Holton, 1982Holton, , 1983Vincent and Reid, 1983). However, many mechanisms are not fully understood today, for example regarding generation, intermittency, and interactions or breaking of GWs (see Fritts and Alexander, 2003, for a review).…”

Retrieval of intrinsic mesospheric gravity wave parameters using lidar and airglow temperature and meteor radar wind data

“…In order to retrieve horizontal wavelengths larger than the FOV of the imager, Takahashi et al (2009); Fritts et al (2014) analysed keogram representations of airglow imager data. In addition to process studies, also long-term observations of OH layer emissions with imaging instruments are employed to derive statistics and seasonal variations of GW parameters at different locations (Walterscheid et al, 1999;Nakamura et al, 1999;Suzuki et al, 2004;Li et al, 2016Li et al, , 2018Shiokawa et al, 2009).…”