The combination of data from different satellite sensors contributes to a better understanding of polynya evolution and reduce uncertainties in satellite data interpretation and geophysical parameter retrieval. Infrared sensors like Envisat AATSR provide temperature and hence indirect information on the ice thickness (thin ice and open water will show higher surface temperatures than thick ice). SAR images offer insights into the structure of the sea ice: ridges and deformation zones will be highlighted in L band images; C-band images provide a better representation of individual thinner level floes. Optical images from RapidEye, Modis or Landsat are close to human perception. They allow identifying snow covered regions and help to improve the interpretation of data from other sensors. By taking into account velocity information derived from a satellite image time series it is possible to identify e.g. fast ice and the polynia outlet region.