Earth observation from space is an important component of research on environmental changes in the Polar Regions and on dynamics of marine ecosystems. Satellite observations are possible over large areas and over long periods. The group "Earth Observing Systems" deals with the analysis of satellite data. The objective is the development of methods for retrieving properties of the polar ice masses, ocean, and land surface from directly measured data. To this end, field campaigns are carried out combining ground- and ship-based, helicopter-, air-, and space-borne data acquisitions. Also utilized are results of computer models which simulate the effects of different characteristics of land ice, sea ice, the upper ocean layer and the land surface on the measured signal.