Albedo evolution of seasonal Arctic sea ice

Abstract

[1] There is an ongoing shift in the Arctic sea ice cover from multiyear ice to seasonal ice. Here we examine the impact of this shift on sea ice albedo. Our analysis of observations from four years of field experiments indicates that seasonal ice undergoes an albedo evolution with seven phases; cold snow, melting snow, pond formation, pond drainage, pond evolution, open water, and freezeup. Once surface ice melt begins, seasonal ice albedos are consistently less than albedos for multiyear ice resulting in more solar heat absorbed in the ice and transmitted to the ocean. The shift from a multiyear to seasonal ice cover has significant implications for the heat and mass budget of the ice and for primary productivity in the upper ocean. There will be enhanced melting of the ice cover and an increase in the amount of sunlight available in the upper ocean.

Seasonal evolution of melt ponds on Arctic sea ice

“…A possible source of this timing offset may be the local snow depth distributions on first-year and multiyear ice. For example, a thin snow cover on one ice type may expose its ice surface to solar radiation earlier in the season, increasing solar absorption, warming, and subsequent melt [Perovich et al, 2002a;Light et al, 2008;Perovich and Polashenski, 2012]. March in situ snow depth data from the NASA/ NRL survey line were evaluated to assess snow depth distributions on each ice type.…”

First-year sea ice melt pond fraction estimation from dual-polarisation C-band SAR – Part 2: Scaling in situ to Radarsat-2

“…During the summer melt season, FYI has a greater areal fraction of melt ponds, termed pond fraction (f p ), than MYI due to a relative lack of topographical controls on melt water flow (Fetterer and Untersteiner, 1998;Barber and Yackel, 1999;Eicken et al, 2002Eicken et al, , 2004Freitag and Eicken, 2003;Polashenski et al, 2012). Melt ponds have a lower albedo (∼ 0.2 to 0.4) compared to ice (∼ 0.6 to 0.8) (Perovich, 1996;Hanesiak et al, 2001a), which promotes shortwave energy absorption into the ice volume and accelerates decay (Maykut, 1985;Hanesiak et al, 2001b). Accelerated heat uptake by pond-covered ice increases the rate at which its temperature related brine volume fraction increases to the point at which the fluid permeability threshold is crossed (Golden et al, 1998) and biogeochemical exchanges with the underlying ocean become possible (see Vancoppenolle et al, 2013, for a review).…”

Towards the Marine Arctic Component of the Pan-Eurasian Experiment

“…The ocean heat capacity per unit volume is over three orders of magnitude larger than that of the overlaying atmosphere, which keeps temperatures much more constant in the ocean than atmosphere. The surface albedo of sea ice ranges from 0.4 for melting ice to 0.85 for ice covered by dry, new snow (Perovich and Polashenski, 2012), compared to less than 0.1 for the open ocean. The heat conductivity of sea ice and, in 25 particular, snow is very low, which allows the maintenance of a very large vertical temperature difference between the ice base (at the freezing point) and the snow surface (in winter as cold as -50°C.…”

“…The surface albedo is critical for the snow and sea ice mass balance during the melt season. It can be observed via remote sensing methods (Riihelä et al, 2013), but in-situ observations are needed to develop better model parameterizations for the dependence of albedo on physical properties of snow, ice, and 15 melt ponds (Perovich and Polashenski, 2012). Further, better observations are needed on light penetration through snow and ice, which is important for the ecosystems in and below the ice.…”