Transmittance and Energy Deposition in Ponded Sea Ice

In an Arctic ocean where the sea ice cover is becoming thinner and more seasonal, first year ice will be more predominant. The surface of first year ice generally has a lower topographic relief than older ice, which may lead to larger areas being covered by melt ponds in the summer. Melt ponds significantly change the surface properties of the sea ice, and thereby modify the energy budget of the ice. We present a study of transmittance and energy deposition of solar radiation in ponded sea ice, based on measurements done in the Nansen basin in summer 2012, and radiative transfer modeling. A plane parallel radiative transfer model is applied, and the usefulness of such a model for a heterogeneous surface like ponded sea ice is discussed. We see that edge effects may make the simulated transmittance of individual points unreliable, but values averaged along entire transects correspond well with measurements. Our results indicate that a plane parallel model may be a useful tool also for studies of larger areas.