Non-linear resonant wave–wave interaction (triad): Case studies based on rocket data and first application to satellite data

Abstract

Gravity waves are well known to have significant influence on the circulation and thermal structure of the atmosphere by transporting energy and momentum. When reaching instability, gravity waves dissipate energy, causing the surrounding wind regime to be modified. Therefore, knowledge about the geographical location of sources of gravity waves (‘GWS’), their dynamical characteristics (e.g. wave spectral information) as well as their energy dissipation mechanisms and rates is essential. Besides pure wave breaking, other possibilities of energy transmission are possible. One prominent mechanism is the non-linear resonant wave–wave interaction (‘triad’). In this paper, an early case study performed by Widdel et al. [1994. Vertical velocities measured at Biscarrosse (44°N) and by EISCAT at Tromso (69.6°N) during DYANA campaign. Journal of Atmospheric and Terrestrial Physics 56, 1779–1796], to look for a possible triad within wind data obtained by the meteorological rocket based foil-chaff cloud technique during the DYANA campaign (DYnamics Adapted Network for the Atmosphere) in 1990, is reinvestigated. Their assumption of seeing a triad in the data is now proved. In addition the observed wave field is dynamically characterized. Energy dissipation rates and the acceleration of the zonal mean flux are estimated applying linear and non-linear theory, respectively. Furthermore, ozone data derived from the satellite-based ERS-2-GOME (Global Ozone Monitoring Experiment) instrument in January 2003 are assimilated into the 3D-chemical transport model ROSE (Research on Ozone in the Stratosphere and its Evolution) to yield synoptic and global coverage and to allow the tracing of dynamical processes. Regions of pronounced dynamical variability are identified and are supposed—at least occasionally—to generate gravity waves. Due to their relatively high vertical resolution, ozone measurements of the ENVISAT-GOMOS (Global Ozone Monitoring by Occultation of Stars) instrument are further used to look for possible indications of triad effects above these gravity wave sources (‘GWSs’).