The Effect of Melt Pond Geometry on the Distribution of Solar Energy Under First‐Year Sea Ice

Abstract

Sea ice plays a critical role in the climate system through its albedo, which constrains light transmission into the upper ocean. In spring and summer, light transmission through sea ice is influenced by its iconic blue melt ponds, which significantly reduce surface albedo. We show that the geometry of surface melt ponds plays an important role in the partitioning of instantaneous solar radiation under sea ice by modeling the three‐dimensional light field under ponded sea ice. We find that aggregate properties of the instantaneous sub‐ice light field, such as the enhancement of available solar energy under bare ice regions, can be described using a new parameter closely related to pond fractal geometry. We then explore the influence of pond geometry on the ecological and thermodynamic sea ice processes that depend on solar radiation.

Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2020

“…The amount of light transmitted through ice cover varies greatly depending on snow cover and the presence of meltwater ponds on the ice [ 238 ]. Studies of transmittance through ice in the Arctic Ocean found that monthly average transparency in the 400–550 nm band varied between 1 and 17% [ 239 ].…”

Under-Ice Phytoplankton Blooms: Shedding Light on the “Invisible” Part of Arctic Primary Production

“…While the overall under-ice light availability increased with decreasing ice thickness over recent decades, small-scale seaice features such as the geometry of melt ponds at the ice surface, ridges, hummocks, leads, and the horizontal distribution of light absorbing ice impurities cause spatial heterogeneity in PAR transmission (Ehn et al, 2008(Ehn et al, , 2011Light et al, 2008;Frey et al, 2011;Katlein et al, 2014Katlein et al, , 2016Matthes et al, 2019;Horvat et al, 2020). The resulting complexity of the under-ice light field creates difficulties in measuring and estimating light availability for UIB phytoplankton since algal cells drifting in under-ice surface waters are exposed to large variations in PAR throughout the day.…”

Floes, the marginal ice zone and coupled wave-sea-ice feedbacks

“…Marginal ice zones (MIZs) are enigmatic, variable and heterogeneous regions covered by sea ice that ‘separate open water and pack ice’ [ 1 ] but that elude simple quantitative description. Typically, the MIZ is contrasted with the region of high-concentration ‘pack’ sea ice observable from passive microwave satellites, that covers the Arctic Ocean basin and hugs the coast of the Antarctic continent [ 2 – 6 ]. MIZs, however, are dynamically distinct areas.…”

“…At any instant, the area of ice-covered regions with energetic ocean surface waves can be much smaller than that ‘influenced’ by waves more generally. In global measurements with the ICESat-2 altimeter, the MIZ was defined as those regions where waves were identified at least 7.5% of the time [ 6 ]—and of 4402 individual observations of sea ice heights in the Southern Ocean, just 304 (7.0%) were identified visually as having waves in them [ 15 ]. The MIZ is dynamic, and ICESat-2 overflights inconsistently sample the constantly varying sea ice surface.…”