THE SEASONAL EVOLUTION OF ALBEDO WITHIN AND ACROSS LAND COVER TYPES, TAYLOR VALLEY, ANTARCTICA

The Dry Valleys of Antarctica rely almost entirely on glacial melt to provide water and support this polar desert ecosystem. Glacial melt dynamics and ground temperature patterns are driven by energy balance dynamics. A slight increase in incoming radiation or decrease in albedo (reflectance) can have large effects on the timing and volume of available water. However, we have yet to accurately measure the albedo across the Dry Valleys landscape and how this changes throughout the season. In this study, we used a camera, GPS, and short wave radiometer to measure the albedo within and across landscape units in the Taylor Valley (soils, glacier surface, and lake ice surface). These instruments were attached to a helicopter and flown on a prescribed path along the valley at approximately 300 feet above the ground surface five different times throughout the season from mid-November to mid-January. As expected, glaciers consistently had the highest albedo throughout the season and the soils had the lowest (with varying snow patch coverage), with the ice-covered lakes in between. All distributions of albedo were statistically significantly different than one another (p-value < 0.05). We hypothesized that albedo would decrease throughout the season as snow melts and more sediment on the surface of lakes and glaciers become exposed. However we found that both glaciers and lakes responded to small snow events and had somewhat persistent high albedo. Furthermore, each glacier generally had different albedos and responded to seasonal snow accumulation and melt differently, trading off which had the highest albedo. These findings highlight the importance of understanding the spatial and temporal variability in albedo and the close coupling of climate and landscape response. As polar change progresses, we can use this new understanding of landscape albedo to better predict how the Dry Valley ecosystems will respond at the landscape scale.