Open AccessAn intense traveling airglow front in the upper mesosphere–lower thermosphere with characteristics of a bore observed over Alice Springs, Australia, during a strong 2 day wave episode
Author(s) -
Walterscheid R. L.,
Hecht J. H.,
Gelinas L. J.,
Hickey M. P.,
Reid I. M.
Publication year - 2012
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2012jd017847
Subject(s) - airglow , thermosphere , atmospheric duct , ionosphere , brightness , atmospheric sciences , front (military) , physics , geology , geophysics , atmosphere (unit) , meteorology , astronomy
The Aerospace Corporation's Nightglow Imager observed a large step function change in airglow in the form of a traveling front in the OH Meinel (OHM) and O 2 atmospheric (O2A) airglow emissions over Alice Springs, Australia, on 2 February 2003. The front exhibited nearly a factor of 2 stepwise increase in the OHM brightness and a stepwise decrease in the O2A brightness. There was significant (∼25 K) cooling behind the airglow fronts. The OHM airglow brightness behind the front was among the brightest for Alice Springs that we have measured in 7 years of observations. The event was associated with a strong phase‐locked 2 day wave (PL/TDW). We have analyzed the wave trapping conditions for the upper mesosphere and lower thermosphere using a combination of data and empirical models and found that the airglow layers were located in a region of ducting. The PL/TDW‐disturbed wind profile was effective in supporting a high degree of ducting, whereas without the PL/TDW the ducting was minimal or nonexistent. The change in brightness in each layer was associated with a strong leading disturbance followed by a train of weak barely visible waves. In OHM the leading disturbance was an isolated disturbance resembling a solitary wave. The characteristics of the wave train suggest an undular bore with some turbulent dissipation at the leading edge.