HR: 13:40h
AN: C23B-01 INVITED    [Abstracts]
TI: Snow on Arctic sea ice
AU: * Perovich, D K
EM: donald.k.perovich@erdc.usace.army.mil
AF: ERDC-CRREL, 72 Lyme Road, Hanover, NH 03755,
AU: Sturm, M
EM: msturm@crrel.usace.army.mil
AF: ERDC-CRREL, 72 Lyme Road, Hanover, NH 03755,
AB: Snow is a pervasive presence on Arctic sea ice for more than nine months of the year. Average snow depths on multiyear ice are about 0.3 – 0.4 m, while first year values are approximately half that. Snow begins to accumulate in summer, continues to deepen during the fall, is fairly stable throughout the winter, and then melts in late spring and early summer. There is considerable spatial variability in snow depth due to wind drifting, with depths ranging from bare ice to more than a meter. The snow depth is often closely tied to the ice type through the interaction of wind drifting and ice roughness. The snow cover and its variability have a profound impact on the thermal and optical properties of the sea ice cover. The influence of snow is enhanced by the contrast in physical properties between snow and ice. Because of its low density snow has a thermal conductivity roughly one-tenth that of sea ice. Deep snow can severely impede winter ice growth. Because of its abundant air-ice interfaces, snow has an optical extinction coefficient 10 times greater than sea ice. Light transmission through snow covered sea ice is small (less than 1%) and due to variations in snow depth can vary by orders of magnitude over horizontal distances of tens of meters. As snow melts there is a decrease in the albedo of the ice cover and an increase in the transmitted light. Changes in the timing of snow melt onset affect both the heat budget of the ice and biological activity in and under the ice. Earlier snow melt onset causes increases in ice ablation and in levels of photosynthetically available radiation under the ice
DE: 1218 Mass balance (0762, 1223, 1631, 1836, 1843, 3010, 3322, 4532)
DE: 1827 Glaciology (0736, 0776, 1863)
DE: 4540 Ice mechanics and air/sea/ice exchange processes (0700, 0750, 0752, 0754)
SC: Cryosphere [C]
MN: 2007 Fall Meeting