Seasonal Evolution of Light Transmission Distributions Through Arctic Sea Ice
Light transmission through sea ice is a critical process for energy partitioning at the polaratmosphere‐ice‐ocean boundary. Transmission of sunlight strongly impacts sea ice melting by absorption,as well as heat deposition, and primary productivity in the upper ocean. While earlier observations reliedon a limited number of point observations, the recent years have seen an increase in spatially distributedlight measurements underneath sea ice using remotely operated vehicles covering a wide range of iceconditions. These measurements allow us to reconstruct the seasonal evolution of the spatial variability inlight transmission. Here we present measurements of sea ice light transmittance distributions from 6 yearsof Arctic under‐ice remotely operated vehicle operations. The data set covers the entire melt period ofCentral Arctic sea ice. Data are combined into a pseudo time series describing the seasonal evolution ofthe spatial variability of sea ice optical properties from spring to autumn freezeup. In spring, snowmeltincreases light transmission continuously, until a secondary mode originating from translucent melt pondsappears in the histograms of light transmittance. This secondary mode persists long into autumn, beforesnowfall reduces overall light levels again. Comparison to several autonomous time series measurementsfrom single locations confirms the detected general patterns of the seasonal evolution of light transmittancevariability. This also includes characteristic spectral features caused by biological processes at the iceunderside. The results allow for the evaluation of three different light transmittance parameterizations,implying that light transmission in current ice‐ocean models may not be accurately represented on largescales throughout all seasons while ice thickness alone is a poor predictor of light transmittance.
AWI Organizations > Climate Sciences > Sea Ice Physics
Helmholtz Research Programs > PACES II (2014-2020) > TOPIC 1: Changes and regional feedbacks in Arctic and Antarctic > WP 1.4: Arctic sea ice and its interaction with ocean and ecosystems
ARK > XXVI > 3
ARK > XXVII > 3
ARK > XXVIII > 3
PS > 101
PS > 106