The State of the Stratosphere Throughout the Seasons: How Well Can Atmospheric Models Explain Infrasound Observations at Regional Distances?

Abstract The stratosphere is the atmospheric layer with strongest impact on long-range infrasound propagation. Natural and anthropogenic signals are efficiently ducted between refraction altitudes of 30 to 60 km reflections ground thus propagated receivers over long distances. direction favorable stratospheric ducting depends state atmosphere, primarily driven by seasonal variation winds. This study uses a dataset ground-truth events two decades all seasons assess station detectability model performance correctly estimate according observations propagation conditions. From 2000 2019, German Aerospace Center facility in Lampoldshausen has conducted ignition tests Ariane 5 main rocket engine. Out 159 engine considered this study, 71 were observed at array IS26 Bavarian forest, located eastward 320 distance. Observations mostly made during wintertime, whereas reversed wind patterns summertime inhibited signal detections. A significant portion wintertime non-detections however corresponded profiles that should enable observations. Using European Centre for Medium-Range Weather Forecasts (ECMWF) analyses ray tracing only two-thirds could be explained existence near-station acoustic shadow zone. It must concluded applied more often than expected unable explain observation regional