Duration of Gravity Waves in OH Airglow Layer Observed by an All-sky Airglow Imager at Maui and Cerro Pachón

Abstract:

OH airglow layer has a typical FWHM of ~7 km centered at ~87 km altitude. Observations from airglow imaging have shown that gravity waves exist most of the time in this layer. The duration or lifespan of wave events has important implications for gravity wave parameterization. In this study, persistent wave events are isolated from long-term airglow measurements from Maui, HI(20.7°N, 156.3°W) and Cerro Pachón, Chile(30.2°S, 70.7°W) by restricting the consecutive wave’s parameters within certain threshold. The probably distribution of the duration of wave events is found be exponentially distributed and the exponents are different at these two different sites. Explanations for such distributions are proposed based on the wave breaking or wave propagation through the airglow layer.