Satellite data can provide valuable information on the spatial and temporal variability of sea ice. Ice concentrations can be derived from passive microwave data such as from the SSM/ I (Special Sensor Microwave/ lmager). These data have been used to study the annual variations in the ice-edge, especially in the timing and form of the ‘ Odden’ feature. The Odden is a tongue of sea ice which forms over the cold Polar Water of the Jan Mayen Polar Current as it is forced north-eastwards by the North Jan Mayen Ridge. In the winter months the Odden dominates the Greenland Sea extending over 1000 km from the coast. Daily monitoring of the SSM/ 1 ice concentrations in February 1988 showed that the Odden could vary up to 350 km in length in a 24-hour period. This is due to the rapid formation of pancake ice and not to movement of the existing ice.