A High-Resolution Observation of the Breakdown of a Kelvin-Helmholtz Instability Modulated by the Passage of an Atmospheric Gravity Wave
Abstract
In February 2016, a new ultra-high resolution airglow imager was installed at the NSF Andes Lidar Observatory located near the summit of Cerro Pachon Chile (30S 71W). This instrument has a 2K x 2K NIR sensitive detector that combined with the front optics has an approximate 30 m pixel resolution. The sensitivity of the instrument allows image exposure times of a few seconds. On the night of February 29/March 1, 2016 gravity waves were seen coincident to a very bright Kelvin-Helmholtz Instability (KHI) event. Besides providing the highest spatial resolution to date of KHI breakdown, there are also indications that this event is modulated by this gravity wave which is propagating perpendicular to the KHI orientation. Na lidar measurements are available that show this is clearly a dynamical instability with the lowest Richardson number (between 0.1 and 0.2) occurring around 88 km, near the peak of the OH emission layer. These data will be discussed in the context of recent detailed modelling of KHI breakdown as well as compared to previous observations of KHI breakdown.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMSA24A..06H
- Keywords:
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- 3334 Middle atmosphere dynamics;
- ATMOSPHERIC PROCESSES;
- 3369 Thermospheric dynamics;
- ATMOSPHERIC PROCESSES;
- 3384 Acoustic-gravity waves;
- ATMOSPHERIC PROCESSES;
- 2427 Ionosphere/atmosphere interactions;
- IONOSPHERE