weather forecasts for the polar regions, especially for the Arctic. On the one hand with the melting of sea ice, the Arctic will be of interest as a shipping route, and on the other hand the conditions in the [...] also influence the weather and climate in the mid-latitudes - for example, in Central Europe and North America. One problem is that there are far too few measurements from the Arctic. With the international [...] measurement campaigns that include ship expeditions, aircraft campaigns, and measuring sites on the sea ice. The main goal is to find out which observations are particularly important for ice and weather