All Physics Faculty Publications

Document Type

Poster

Publication Date

4-2-2024

Abstract

Since their discovery over the Hawaii Islands in the early 1990's (Taylor et al., 1995), prominent bore-like waves (initially termed mesospheric frontal events), have now been observed by a number of researchers at equatorial (e.g., Medeiros et al., 2001; Smith et al., 2005), mid (Smith et al., 2003; She et al., 2004), and most recently high latitudes (Nielsen et al., 2006; Stockwell et all., 2006). These unusual gravity wave events are characterized in the nightglow emissions by a sharp leading front usually followed by a coherent train of waves that grow in number with time. Often times, the front exhibits a reversal in contrast when images in two emission layer separated by several km (see figure above). Dewan and Picard (2001) have shown that these features are consistent with a ducted perturbation (akin to a river bore) propagating horizontally at mesospheric heights. Subsequent lidar, imager and TIMED satellite measurements have demonstrated the existence of a temperature inversion layer supporting the ducted wave hypothesis (smith et al., 2003, 2005; She et al., 2004). However, to date there have been no direct height measurements of such bore events. This poster presents novel two-station measurements of mesospheric bores imaged near simultaneously in the OH emission at equatorial latitudes during 2006. Several bore events have been identified in both data sets. Their signatures are faint but sufficient to permit an initial investigation of their height and structure using tomographic reconstruction techniques.

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