Stratospheric Gravity Waves Excited by a Propagating Rossby Wave Train—A DEEPWAVE Case Study

Kurzfassung

There are only a few airborne observations of middle-atmospheric gravity waves in the Southern Hemisphere (Fritts et al. 2016; Rapp et al. 2021). Research flights to latitudes south of 608S are especially rare (e.g., Tuck et al. 1989; Parish and Bromwich 1989; Carli et al. 2000). These early airborne campaigns were mainly motivated by ozone research (Tuck et al. 1997; Tuck 2021) but also documented mesoscale temperature fluctuations (Gary 2008), gravity waves (Bacmeister et al. 1990), and turbulence (Tuck 2008). One of the more recent research flights was conducted during the Deep Propagating Gravity Wave Experiment (DEEPWAVE) experiment in July 2014 using the instrumented NSF/NCAR Gulfstream V research aircraft from an operating base in Christchurch, New Zealand (Fritts et al. 2016). The DEEPWAVE research flight 25 (RF25) went straight southwest from New Zealand to about 638S and returned along the same path back, see Fig. 1. The scientific objectives of this survey flight into the atmospheric flow above the Southern Ocean were based on operational forecasts by a suite of high resolution numerical weather prediction (NWP) models (Fritts et al. 2016, their Table 3) and were formulated as follows prior to the actual flight.