We use observations from one of the SOUTHTRAC (Southern Hemisphere
Transport, Dynamics, and Chemistry) Campaign flights in Patagonia
and the Antarctic Peninsula during September 2019 to analyze
possible sources of gravity wave (GW) in this hotspot during austral
late winter and early spring. Data from two of the instruments
onboard the German High Altitude and Long Range Research Aircraft
(HALO) are employed: the Airborne Lidar for Middle Atmosphere
research (ALIMA) and the Basic HALO Measurement and Sensor System
(BAHAMAS). The former provides vertical temperature profiles along
the trajectory while the latter gives the three components of
velocity and temperature at the flight position. GW induced
perturbations are obtained from these observations. We include
numerical simulations from the Weather Research and Forecast (WRF)
model to place a four-dimensional context for the GW observed during
the flight and in order to present possible interpretations of the
measurements, as for example the orientation or eventual propagation
sense of the waves may not be inferred using only data obtained
onboard. We first evaluate agreements and discrepancies between the
model outcomes and the observations. This allowed us an assessment
of the WRF performance in the generation, propagation and eventual
dissipation of diverse types of GW through the troposphere,
stratosphere and lower mesosphere. We then analyze the coexistence
and interplay of mountain waves (MW) and non-orographic (NO) GW. The
MW dominate above topographic areas and in direction of the
so-called GW belt whereas the latter waves are mainly relevant above
oceanic zones.