Mech, Mario; Crewell, Susanne; Ehrlich, André; Klingebiel, Marcus; Wendisch, Manfred; van Gelder, Lars; Bruder, Lena; Krobot, Pavel; Jansen, Friedhelm; Panton, James; Vicencio, Jose; Pant, Awadhesh; Genz, Christa; Drude, Johanna; Staudinger, Ilga; Ebell, Kerstin; Schnotalle, Patrick; Schäfer, Michael; Müller, Joshua; Schoch, Patrizia; Brückner, Marlen; Eichholz, Hannah Marie; Maahn, Maximilian; Foth, Andreas; Kalesse-Los, Heike; Aydin, Beryl; Gobert, Clemens; Stöhr, Maximilian; Glöckner, Helene; Schnitt, Sabrina: Collection of data sets for the Clouds over complex environment (COMPEX) campaign, carried out in early spring 2026 around Svalbard [dataset bibliography]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.996627 (dataset in review)

The Clouds over complex environment (COMPEX) airborne campaign is a joint project of the University of Cologne and Leipzig University and is embedded in the Transregional Collaborative Research Centre TR 172 Arctic Amplification: Climate-Relevant Atmospheric and Surface Processes, and Feedback Mechanisms ((AC)³). It has been conducted in early spring 2026 out of Longyearbyen on Svalbard with the Polar 5 research aircarft of the Alfred Wegener Institute for Polar and Marine Research. The Polar research aircraft has equipped with a comprehensive remote sensing payload, including a dual-frequency cloud radar combining G- and W-band measurements, complemented by lidar, radiometric, imaging, and in situ observations. In total, 15 research flights with around 60 flight hours have been performed during the five weeks campaign. The measurement region included Kongsfjorden, the Ny-Ålesund area, and the adjacent Arctic Ocean, including sea ice and the marginal sea ice zone north, northwest, and southeast of the archipelago in different meteorological regimes, with a focus on low-level cloud systems and their interaction with the surface and boundary layer. In addition, two collocated flights with the EarthCARE satellite have been performed.