Remote Sens. Environ. 140, 604–613 (2014)

Knowledge of the reflectivity, or albedo, of Arctic sea-ice is important to understand the surface energy budget and the Earth's radiative balance. At present, observations are available from optical satellite instruments, which are limited by cloud cover and low Sun elevations in late summer and autumn — the melt–refreeze period. These constraints mean that optical methods require several days of data to be averaged to provide a representative estimation of albedo.

Vesa Laine and colleagues from the Finnish Meteorological Institute, Helsinki, investigate a new technique for estimating sea-ice albedo that can overcome these limitations. They find that a microwave-based method of estimation is capable of providing daily observations without gaps. Microwave observations are not limited by solar angle, cloud cover or the need for atmospheric correction. The higher temporal resolution of this coverage allows changes in surface albedo to be linked to short-term atmospheric and ocean processes, leading to a better understanding of seasonal cycles.