HALO-(AC)³ is the field study that aims at investigating warm air intrusions into the Arctic and cold air outbreaks.  We will cove larger spatial scales with a particular emphasis on process studies of important examples of Arctic mid–latitude linkages by applying the High Altitude and Long Range Research Aircraft (HALO), and the AWI polar aircrafts P5 & P6 for coordinated research flights over the Arctic as well as simultaneous measurements of the tethered balloon called BELUGA that will be based in Spitzbergen. More about HALO-(AC)³