Special issue  

Gravity waves (GWs) are a ubiquitous phenomenon in a stably stratified atmosphere. GWs are excited by flow over orography and by convection or jet streams and fronts, and may propagate both horizontally and vertically over large distances. Thus, they lead to a significant vertical and horizontal transport of energy and momentum which so far is hardly appropriately accounted for in numerical weather prediction and climate models, which mainly rely on simplified parametrization schemes. In order to investigate sources, propagation, dissipation and impact of GWs, a number of large internationally coordinated research campaigns have been conducted over the past few years. These campaigns involve observations with research aircraft, satellites, research balloons, and ground-based instruments, as well as related modelling efforts. Specifically, these are the series of GW-LCYCLE (Gravity Wave Life CYCLE) campaigns conducted in northern Scandinavia in winter 2013 and 2015/16 as well as the NSF-DEEPWAVE (The DEEP PROPAGATING GRAVITY WAVE EXPERIMENT) campaign conducted in June/July 2014 from New Zealand. The German contributions to these activities were funded in the scope of the ROMIC (Role of the Middle atmosphere in Climate) research focus of the German Ministry for Education and Research as well as the MS-GWAVES (Multi Scale dynamics of Gravity WAVES) research unit funded by the German Science Foundation. For this special issue, we invite contributions describing observations and related modelling studies focusing on results achieved during these field campaigns. However, beyond studies specifically addressing results obtained in the framework of GW-LCYCLE and DEEPWAVE, we also invite any related studies dealing with GW processes and their impact on the atmosphere. Within this framework, contributions focusing on both scientific and methodological aspects will be considered.