The CONIDA project centers on two four-week HALO aircraft campaigns: CONIDA-Night in November–December 2028 and CONIDA-Day in June–July 2029. Building on HALO–(AC)³, CONIDA shifts the scientific focus from thermodynamic airmass properties to cloud evolution, precipitation formation, and impacts on the Arctic surface energy budget. A key goal is to identify how airmass transformation processes differ between polar night and polar day, enabling a clearer understanding of the seasonal mechanisms driving Arctic amplification. Because
clouds play contrasting roles in winter and summer—affecting lapse rate feedbacks, surface albedo, and sea ice formation—the two campaigns will provide critical insight into how cloud–radiation interactions shape the Arctic climate system across seasons. To capture these changes, CONIDA aims to quantify changes in cloud and precipitation characteristics during warm-air intrusions (WAIs) and cold-air outbreaks (CAOs), along with associated influences from atmospheric stability, ocean-ice temperature gradients, and solardriven albedo effects. Expanding on prior cloud studies, the project will derive concrete microphysical and precipitation properties that can be directly linked to surface energy budget variability. This will open new pathways for understanding Arctic cloud–precipitation–radiation feedbacks, which differ fundamentally between polar night and day. 

The first main objective of CONIDA is to perform quasi-Lagrangian observations of airmass transformation processes during WAIs and CAOs, with emphasis on cloud–precipitation–radiation interactions and their surface energy consequences. HALO’s long range, high altitude capability, and advanced remote sensing payload make it uniquely suited for repeated sampling of the same air parcels across open water, the marginal ice zone, and sea ice. Coordinated flight planning guided by trajectory forecasts will enable multi-stage sampling of evolving airmasses. Additional low-altitude in situ observations are planned using the Polar 6 aircraft from the Alfred Wegener institute (AWI) to capture small-scale processes in the lower troposphere. 

CONIDA’s second main objective is to evaluate and improve numerical atmospheric models by constructing detailed modeling case studies driven by the observational dataset. These studies will examine how factors such as distance to the ice edge, sea-ice concentration, and topography influence cloud–precipitation–radiation processes. Model evaluation will span scales from large eddy simulations following airmasses along Lagrangian paths to regional mesoscale models. Sensitivity experiments informed by CONIDA’s observations will help isolate key processes linking Arctic amplification to mid-latitude weather.