It is proposed to include in the Arctic Deployment 2003 of the Airborne Remote Sensing Facility a flight with the objective of obtaining Airborne Thematic Mapper (ATM) and Compact Airborne Spectrographic Imager (casi) data over sea-ice under predominantly clear-sky conditions. In summer, melt-ponds form on sea-ice, causing bias in microwave estimates of sea-ice concentration. With the data collected we will investigate the spectral signature of ponds at a high spatial resolution, at which individual melt ponds will be resolvable. This is with a view to routine use of lower-spatial-resolution space-based sensors to improve current estimates of summer sea-ice concentration in a multi-spectral retrieval.