Dynamics of Orographic Gravity Waves Observed in the Mesosphere over the Auckland Islands during the Deep Propagating Gravity Wave Experiment (DEEPWAVE)

A groundbreaking study reveals that orographic gravity waves generated by airflow over the Auckland Islands significantly impact mesospheric dynamics. During the DEEPWAVE experiment, large-amplitude wave oscillations were detected at altitudes of 78–83 km, leading to intense wave breaking beneath a zero-wind region. These waves, influenced by migrating semidiurnal tides, caused rapid westward flow accelerations (~350 m/s/h) and substantial dynamical heating (~8 K/h). The research used high-altitude reanalysis data and a 3D Fourier gravity wave model to replicate observed wave fields, confirming the islands' role in altering middle-atmospheric circulation and climate during austral winter. This finding underscores the broader implications of subantarctic island-generated waves on global atmospheric dynamics.

Eckermann, S. D., Broutman, D., Ma, J., Doyle, J. D., Pautet, P.-D., Taylor, M. J., Bossert, K., Williams, B. P., Fritts, D. C., & Smith, R. B. (2016). Dynamics of Orographic Gravity Waves Observed in the Mesosphere over the Auckland Islands during the Deep Propagating Gravity Wave Experiment (DEEPWAVE). Journal of the Atmospheric Sciences, 73(10), 3855–3876. https://doi.org/10.1175/jas-d-16-0059.1