Airborne campaign MOSAiC ACA takes place in Longyearbyen, Svalbard, from 28 August until 16 September 2020. (AC)³ partners from Unis Leipzig, Cologne, and Bremen, from AWI and Deutsches Zentrums für Luft- und Raumfahrt (DLR) are involved.

(AC)³ is a major German player within the international MOSAiC consortium in which 17 nations are involved. (AC)³ will lead two of the planned airborne campaigns (MOSAiC-Airborne observations in the Central Arctic, MOSAiC-ACA) using the Polar 5 and Polar 6 aircraft of AWI to complement the observations on RV Polarstern. The airborne campaigns are scheduled to take place in March/April and in August/September 2020. Projects A03, B03, B04, C01 will be involved in these airborne campaigns.

The general scientific goal of the MOSAiC ACA 2020 summer campaign is to study the impact of clouds on Arctic amplification, look at air mass transformation processes, and collect data on sea ice distribution in the inner Arctic during summer-time conditions. More specifically, the campaigns aim to obtain comprehensive data sets of a diversity of atmospheric parameters including cloud and aerosol particles and of the energy (turbulent, radiative) and momentum fluxes through clouds. These data will help to quantify the role of clouds in the lower Arctic atmosphere over the Northern Fram Strait. Similar to the previous (AC)³ campaigns ACLOUD (2017), PAMARCMIP (2018), and AFLUX (2019), our strategy is to measure above, in, and below clouds with a large suite of sensors for in situ and remote sensing observations. Using the collected data, it will become possible to better understand the seasonal variability of energy and momentum fluxes, cloud characteristics, and cloud-related processes, since the previous campaigns were carried out in late winter and early summer. Furthermore, we will be able to better investigate clouds and their formation processes over the Arctic Ocean, and to identify the role of aerosol particles and turbulent eddies in cloud processes. This includes the measurements of aerosols (fine dust) and turbulent eddies. For these purposes, a comprehensive suite of instrumentation is installed on Polar 5 including a nose boom with a five-hole probe, a Lidar, a photometer, a cloud radar, as well as other remote sensing instruments to measure the radiation scattered and emitted by clouds, and finally, in-situ cloud probes and a drop sounding system.