Observing and Modeling the Surface Scattering Layer of First-Year Arctic Sea Ice

摘要

The goal of this work is to increase our quantitative understanding of the partitioning of incident solar (shortwave) radiation by sea ice. The partitioning of shortwave radiation into components backscattered to the atmosphere, absorbed by the ice, and transmitted to the ocean is central to the ice-albedo feedback mechanism, the mean annual cycle of ice thickness, mechanical properties of the ice, and the quality and quantity of light available to under-ice biological communities. This partitioning is known to depend on the presence of surface scattering layers (SSLs). We conducted field observations and model simulations of radiative transfer within the surface layer and interior layers of sea ice. Results have been used to improve characterization of the properties of bare and ponded ice for the purpose of understanding the surface energy and mass balances of sea ice during summer. Three broad concepts have emerged from this work: (i) a 3-layer structure for specifying the vertical variation of optical properties of both bare and ponded sea ice, (ii) the optical properties found in the ice interior are independent of time, and (iii) a picture of the evolution of scattering near the surface of bare and ponded ice as the melt season progresses.