Characterization of a Double Mesospheric Bore Over Europe

Abstract

Observations of a pair of mesospheric bore disturbances that propagated through the nighttime mesosphere over Europe are presented. The observations were made at the Padua Observatory, Asiago (45.9°N, 11.5°E), by the Boston University all‐sky imager on 11 March 2013. The bores appeared over the northwest horizon, approximately 30 min apart, and propagated toward the southeast. Using additional satellite and radar data, we present evidence indicating the bores originated in the mesosphere from a single, larger‐scale mesospheric disturbance propagating through the mesopause region. Furthermore, the large‐scale mesospheric disturbance appeared to be associated with an intense weather disturbance that moved southeastward over the United Kingdom and western Europe during 10 and 11 March.

Geographical and Seasonal Variability of Mesospheric Bores Observed from the International Space Station

“…Sharp propagating fronts of brightness jump or drop that are followed by a train of waves or turbulence have been occasionally observed in mesospheric airglow by ground-based imagers. Since Taylor et al (1995) first reported this type of event over Hawaii, similar wave events have been reported at various locations (e.g., Fechine et al, 2005;Giongo et al, 2018;Li et al, 2013Li et al, , 2019Narayanan et al, 2009;Nielsen et al, 2006;She et al, 2004;Smith et al, 2003Smith et al, , 2005Smith et al, , 2017. Dewan and Picard (1998) explained the Taylor et al (1995) event as a propagating discontinuity in a stable layer or duct, and they named it a mesospheric bore.…”

“…Some previous studies have shown the association between mesospheric bores and tropospheric cold front systems (Smith et al, , ; Yue et al, ). They reported a concurrent tropospheric cold front system with a similar alignment of the mesospheric bore and suggested that the gravity waves generated from the cold front system could have excited the mesospheric bore.…”

“…This type of a bore front formation from large-scale gravity waves was reported by Yue et al (2010) by using ground-based observations. Some previous studies have shown the association between mesospheric bores and tropospheric cold front systems (Smith et al, 2003(Smith et al, , 2017Yue et al, 2010). They reported a concurrent tropospheric cold front system with a similar alignment of the mesospheric bore and suggested that the gravity waves generated from the ©2019.…”

Evolution of a Mesospheric Bore in a Duct Observed by Ground‐Based Double‐Layer Imagers and Satellite Observations Over the Tibetan Plateau Region

“…where N is the Brunt-Väisälä frequency, k = 2π/λ is the horizontal wavenumber, c is the horizontal phase speed of the bore, u is the wind speed in the direction of bore propagation measured by meteor radar, and u zz is the second derivative of u with height z. Equation (13) is only valid under the WKB approximation, which means the vertical scale of wind and temperature profiles are larger than the vertical wavelength of the wave (Nappo, 2002;Smith et al, 2017). Figure 12 presents vertical wave number m 2 profiles derived from the meteor radar wind profiles shown in Figure 5b and the temperature profiles shown in Figure 6 at P1, P2, and P3.…”

“…The bore divides nightglow into bright and dark regions. Since a mesospheric bore was first reported by Taylor et al (), many researchers have devoted much effort to investigating this interesting phenomenon using ground‐based all‐sky airglow imagers (Li et al, ; Medeiros et al, ; Narayanan et al, ; Nielsen et al, ; She et al, ; Shiokawa et al, ; Smith et al, , , , ; Yue et al, ), satellite observation (Miller et al, ), and models (Dewan & Picard, , ; Laughman et al, ; Seyler, ).…”