Climatology reflected by infrasound travel-times sampling the stratosphere in its transition between summer and winter

Like seismic waves traveling through the solid earth, infrasound waves traveling through the atmosphere are also sensitive to the medium properties – in particular to temperature and wind. The exploitation of this information is particularly interesting in regions and altitude ranges where other
measurements are sparse. In this work, we look at the climatology from first-arrival travel-times using a dataset of infrasound observations from northern Scandinavia, this is, in the context of stratospheric temperatures.

The same dataset has recently been exploited to estimate tropospheric and stratospheric cross-winds. This dataset spans 30 years and corresponds to explosions that are due to the destruction of ammunition at a military site in Finland conducted over the months of August and September; hence, it
covers the period of transition from summer to winter stratosphere. The transition between summer and winter stratosphere is clear in the data. However, a significant travel-time variation between years produces inconclusive results when inferring stratospheric temperature trends over the 30 years analyzed. Still, when comparing the travel-times against regional stratospheric temperatures represented in atmospheric re-analysis models, there is a correspondence between models and infrasound data.