The general objectives of the HALO-(AC)³ mission are:

1. To perform quasi-Lagrange observations of air-mass transformation processes during meridional transports with a particular focus on pronounced warm air intrusions and marine cold air outbreaks, and
2. To test the ability of numerical atmospheric models to reproduce the measurements, which then can be applied to investigate the linkages between Arctic amplification and mid-latitude weather.

In addition, we will operate (in close collocation with HALO) two further low-flying aircraft (Polar 5: Active and passive remote sensing measurements; and Polar 6: In situ measurements of clouds, aerosol particles, and radiation) funded by AWI to probe smaller-scale processes in the lower troposphere (below 3-5 km altitude) in a similar coordinated way as done during the ACLOUD campaign.