HR: 0800h
AN: C41C-0217    [Abstracts]
TI: The Seasonal Evolution of Sea Ice Floe Size Distribution
AU: * Perovich, D K
EM: Donald.K.Perovich@erdc.usace.army.mil
AF: Cold Regions Research and Engineering Laboratory (CRREL), 72 Lyme Road, Hanover, NH 03755-1290
AU: Maykut, G A
EM: maykut@atmos.washington.edu
AF: University of Washington, Department of Atmospheric Sciences Box 351640, Seattle, WA 98195-1640
AU: Jones, K F
EM: Kathleen.F.Jones@erdc.usace.army.mil
AF: Cold Regions Research and Engineering Laboratory (CRREL), 72 Lyme Road, Hanover, NH 03755-1290
AB: The Arctic sea ice cover undergoes large changes over an annual cycle. In winter and spring the ice cover consists of large, snow-covered plate-like ice floes, with very little open water. By the end of summer the snow cover is gone and the large floes have broken into a complex mosaic of smaller, rounded floes surrounded by a lace of open water. This evolution strongly affects the distribution of the solar radiation deposited in the ice-ocean system and consequently the heat budget of the ice cover. In particular, increased floe perimeter can result in enhanced lateral melting. We attempt to quantify the floe evolution process through the concepts of a floe size distribution and a breaking function. A time series of aerial photographic surveys made during the SHEBA field experiment was analyzed to determine evolution of the floe size distribution from spring through summer. Based on earlier studies, we assumed the floe size distribution could be represented by a two-parameter power law F(D) = a D$^{-b}$, where D is the floe diameter and a and b are the two parameters. The size of small floes could be measured directly from the images. For larger floes they were truncated at the edge of the photographs, measurements of total ice area and perimeter were used to estimate two parameters of the size distribution. As summer progressed, there was a decrease in the magnitude of the exponent as the size distribution shifted towards smaller floes. We are developing simple parameterizations of the evolution of the floe size distribution that can be incorporated into large-scale sea ice models.
DE: 3349 Polar meteorology
DE: 4540 Ice mechanics and air/sea/ice exchange processes
DE: 1635 Oceans (4203)
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting