MOSAiC—Observing and Understanding the New Arctic Ocean (Seminar)

Jones Seminar on Science, Technology, and Society.
Don Perovich, Professor of Engineering, Dartmouth College.
Friday, October 8, 2021.

The Arctic sea ice cover is in decline, with decreases in ice extent, ice thickness, and ice age. This ice cover plays a critical role in the global climate system, acting as both an indicator and an amplifier of climate change. It is imperative that we observe and understand the ongoing changes in Arctic sea ice. The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) program is designed to examine the causes and consequences of a diminished sea ice cover.

MOSAiC is taking an interdisciplinary approach, examining interactions between the atmosphere, ice, ocean, ecosystem, and biogeochemistry. It used models to inform the observational strategy and is now using observational results to improve models. The sea ice program focused on the interaction of sunlight with the ice cover, the mass balance of the ice cover, and the deposition and transport of snow. The albedo of the ice cover is a key driver of the summer melt season. Observations made during MOSAiC show large spatial variability in albedo driven largely by differences in the physical properties of the surface. The temporal evolution of the areally averaged albedo displays a season cycle from values of about 0.85 in the spring to a minimum of approximately 0.40 at the end of summer melt. Comparison of observed albedos with results from the Community Earth System Model show good agreement, but for the wrong reasons.