Observations of the source and propagation of atmospheric gravity waves

Abstract

Atmospheric gravity waves play an important role in transporting energy from one region of the atmosphere to another. But the sources of these waves and their propagation characteristics are not fully understood. Here we report on measurements made during the Worldwide Atmospheric Gravity Wave Study (WAGS) in the auroral source region showing that enhanced Joule heating and Lorentz forcing lead to the generation of large-scale thermospheric waves. Both of these source mechanisms depend on the auroral electric field and the intrinsic periodicity of that field determines the periodicity of waves observed an hour later propagating southwards over the UK. These observations provide the first confirmation of a link between a periodic auroural source and a large-scale gravity wave.