AUTHOR=Yu Miao , Lu Peng , Cheng Bin , Leppäranta Matti , Li Zhijun 

TITLE=Impact of Microstructure on Solar Radiation Transfer Within Sea Ice During Summer in the Arctic: A Model Sensitivity Study

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.861994

DOI=10.3389/fmars.2022.861994

ISSN=2296-7745

ABSTRACT=The recent rapid changes in Arctic sea ice have occurred not only in ice thickness and extent, but also in the microstructure of ice. Knowledge of the role of internal variations on partitioning of incident solar shortwave radiation within the ice and upper ocean is important. This study investigated the sensitivity of the optical properties of summer sea ice on ice microstructures such as the volume fraction, size, and vertical distribution of gas bubbles, brine pockets, and particulate matter (PM). The results show that gas bubbles are the predominant scatterers within sea ice. Their effects on the scattering coefficient and ice albedo are 5 and 20 times stronger, respectively, than the effect of brine pockets. Albedo and transmittance of ice decrease with higher concentration and larger size of PM particles. A 4-cm top layer of ice with high PM concentration (50 g/m3) results in a 10% increase in radiation absorption. The role of ice microstructure in the partitioning of radiation transfer is more important for seasonal than for multiyear ice, and more important for ponded than for snow-covered ice. Varying ice microstructure can obviously alter the solar radiation transfer in the ice-ocean system even with a constant ice thickness. Thus it is suggested that numerical modeling should take the variable microstructure of sea ice into account to improve model accuracy and to understand the role of internal variations in Arctic sea ice, especially in summer.