The polar regions are expected to be particularly sensitive to anthropogenic global change. Due to the difficulties in modeling high latitude climate and the logistical challenges with polar field work, satellite remote sensing will have an increasingly important role to play in polar climate research. For studies of atmospheric radiation and meteorology, accurate cloud detection and classification is crucial. Modern methods for polar cloud classification utilize both multispectral threshold and automated pattern recognition techniques. For monitoring sea ice concentration, passive microwave sensors offer an all-weather advantage over visible or infrared scanners, although over clear-sky scenes the latter can provide a much finer spatial resolution. The various algorithms for satellite retrieval and remote sensing in the polar regions are constantly being refined and improved.