ACLOUD and AFLUX are 2 joint aircraft campaigns of different German universities and research institutes (listed below) embedded in the Transregional Collaborative Research Centre TR 172: ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)³.

The general goals of both aircraft campaigns ACLOUD (17 May -26 June 2017) and AFLUX (16th March - 15th April 2019) were/are to obtain comprehensive data sets of a diversity of atmospheric parameters, which help to better understand and quantify the role of clouds in the lower Arctic atmosphere. A special focus is on the amplified climate change in the Arctic. To that aim measurements during ACLOUD and AFLUX were/are carried out in, above, and below clouds over sea ice and over open ocean. Longyearbyen (Svalbard) is/was used as a base for the aircraft during both campaigns.

The measurements of ACLOUD have already partly been analyzed in combination with different kinds of atmospheric models. Scientists from Section Polar Meteorology were responsible for the measurement of energy fluxes caused by turbulence. It has been shown that clouds have a large impact on the generation of turbulence but the effect depends strongly on the forcing conditions such as wind regimes and surface characteristics.

One can expect a seasonal dependence of the cloud impact. Thus the late spring/early summer measurements during ACLOUD are presently accomplished by late winter/early spring measurements during the AFLUX campaign, which is carried out from 16th March to 15th April 2019. Specific goals of participating scientists from Section Polar Meteorology at AWI are again related to the turbulent transport of energy and momentum in and below clouds.

ACLOUD employed two research aircraft, Polar 5 & 6, operated by the Alfred Wegener Institute. During about 20 research flights with each aircraft properties of cloud and aerosol particles, trace gas concentration, and energy fluxes were measured in the atmospheric column. In situ measurement techniques and remote sensing instruments were applied.

AFLUX employs only Polar 5, the focus is on turbulence, radiation, and cloud particle measurements. About 12-14 flights are expected.

Particpating institutes

• LIM Leipzig Institute for Meteorology, University of Leipzig, Germany
• IGM Institute for Geophysics and Meteorology, University of Collogne, Germany
• AWI Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven and Potsdam, Germany
• TROPOS Leibniz Institute for Tropospheric Research, Leipzig, Germany
• IPA Institute for Atmospheric Physics, Johannes Gutenberg University Mainz, Germany
• MPI-C Max Planck Institute for Chemistry, Mainz, Germany
• KIT Karlsruhe Institute for Technology, Germany
• LaMP Laboratoire de Météorologie Physique, Clermont-Ferrand, France