Interference of Gravity Waves Above the Antarctic Peninsula Studied Using a Spectral Rotary Method During the SOUTHTRAC Campaign

Abstract

In the context of the SOUTHTRAC (Southern Hemisphere Transport, Dynamics, and Chemistry) campaign, carried out by a specialized aircraft in the southern Patagonia, one of the flights was analyzed using a spectral rotary method in order to understand the vertical energy transport of gravity waves (GWs) above the Antarctic Peninsula. The interpretations and capabilities of the rotary method were first tested using a set of synthetic waves. The importance of the flight chosen for this study was due to the high resolution data obtained over the Antarctic Peninsula and southern Patagonia. The most valuable data due to its wide observational window, collected by the on-board ALIMA (Airborne LiDAR for Middle Atmospheric Research) LiDAR, provided temperature profiles roughly from 20 to 70 km height; and a set of sensors that registered the wind in three dimensions, pressure, and temperature at flight level. A set of large amplitude gravity waves were detected by ALIMA, one of them likely emitted during geostrophic adjustment in the vicinity of a jet near the Andes, and a mountain wave generated over the Antarctic Peninsula. Finally, the GROGRAT (Gravity-wave Regional or Global Ray Tracer) model was implemented, which combined with additional tools and analysis allowed to infer the trajectory of the wave detected in the Drake Passage.