Journal cover Journal topic
Annales Geophysicae An open-access journal of the European Geosciences Union
Ann. Geophys., 27, 3213-3224, 2009
https://doi.org/10.5194/angeo-27-3213-2009
© Author(s) 2009. This work is distributed under
the Creative Commons Attribution 3.0 License.
 
19 Aug 2009
Analysis and modeling of ducted and evanescent gravity waves observed in the Hawaiian airglow
D. B. Simkhada1, J. B. Snively1, M. J. Taylor1, and S. J. Franke2 1Utah State University, Center for Atmospheric and Space Sciences, 4405 Old Main Hill, Logan, UT 84322-4405, USA
2University of Illinois at Urbana-Champaign, Department of Electrical and Computer Engineering, 320 CSL, 1308 W. Main Street, Urbana, IL 61801, USA
Abstract. Short-period gravity waves of especially-small horizontal scale have been observed in the Maui, Hawaii airglow. Typical small-scale gravity wave events have been investigated, and intrinsic wave propagation characteristics have been calculated from simultaneous meteor radar wind measurements. Here we report specific cases where wave structure is significantly determined by the local wind structure, and where wave characteristics are consistent with ducted or evanescent waves throughout the mesopause region. Two of the documented events, exhibiting similar airglow signatures but dramatically different propagation conditions, are selected for simple numerical modeling case studies. First, a Doppler-ducted wave trapped within relatively weak wind flow is examined. Model results confirm that the wave is propagating in the 85–95 km region, trapped weakly by evanescence above and below. Second, an evanescent wave in strong wind flow is examined. Model results suggest an opposite case from the first case study, where the wave is instead trapped above or below the mesopause region, with strong evanescence arising in the 85–95 km airglow region. Distinct differences between the characteristics of these visibly-similar wave events demonstrate the need for simultaneous observations of mesopause winds to properly assess local propagation conditions.

Citation: Simkhada, D. B., Snively, J. B., Taylor, M. J., and Franke, S. J.: Analysis and modeling of ducted and evanescent gravity waves observed in the Hawaiian airglow, Ann. Geophys., 27, 3213-3224, https://doi.org/10.5194/angeo-27-3213-2009, 2009.
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