Surface albedo measurements over Antarctic sites in summer

Abstract

Surface albedo data from several Antarctic sites were compared to determine spatial and temporal variability in albedo. The highest degree of variability was observed at Hells Gate Station on the Ross Sea coast. The temperature close to the melting point and the reduced katabatic winds during summer allowed a strong metamorphism of the snow. At Neumayer, a coastal station by the Weddell Sea, snowfall and drifting snow were more frequent, and the surface albedo was constantly high. The albedo increased by an average of 0.07 from clear days to days with snowfall and overcast sky. Surprisingly, the hourly variation in albedo at Hells Gate Station showed a trend similar to the one observed at Neumayer Station and at Dome Concordia Station on the high plateau, when only those days with fresh snow at the surface were considered. The albedo steadily decreased during the day for solar zenith angles less than 80°. Snow metamorphism, sublimation during the day, and refreezing and/or crystal formation/precipitation during the night can explain the observed trend. To represent the daily trend in albedo over ice and fresh snow, we propose two parameterizations, which can be easily applied over other Arctic and Antarctic sites in summer. Small‐ and large‐scale surface roughness elements can result in distortion in the measured albedo. The data at Reeves Névé Station show the effect produced on the albedo by changing slightly the sampling area immediately over a sastruga.