aircraft operation illustration the coordination activities at Polarstern and Ny Alesund (Photo: Alfred-Wegener-Institut) ACLOUD and AFLUX are 2 joint aircraft campaigns of different German universities 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 [...] 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