HR: 0800h
AN: C41C-0209    [Abstracts]
TI: Evaluation of Efficiency and Impact of a Hierarchy of Parameterizations of Temporal Evolution of Sea-Ice Salinity Vertical Profile in One-Dimensional Thermodynamic Models
AU: * Vancoppenolle, M
EM: vancop@astr.ucl.ac.be
AF: Institut d'Astronomie et de G\'eophysique G. Lema\^itre, Universit\'e Catholique de Louvain, Chemin du cyclotron, 2, Louvain-la-Neuve, 1348 Belgium
AU: Bitz, C M
EM: bitz@apl.washington.edu
AF: Polar Science Center, Applied Physics Laboratory, 1013 NE 40th St., Seattle, WA 98105 United States
AU: Fichefet, T
EM: fichefet@astr.ucl.ac.be
AF: Institut d'Astronomie et de G\'eophysique G. Lema\^itre, Universit\'e Catholique de Louvain, Chemin du cyclotron, 2, Louvain-la-Neuve, 1348 Belgium
AB: The results and impact of three different parameterizations of temporal evolution of the vertical salinity in a one-dimensional energy-conserving sea-ice model are assessed. The first and simplest parameterization (1) gives a time-independent bulk salinity in terms of ice thickness and age of the ice. The second one (2) simulates the evolution of the bulk salinity according to brine-drainage processes that are chosen empirically, assuming a vertically constant salinity for first-year (FY) ice and a linear profile of salinity for multi-year (MY) ice. The last one (3), the most complex, physically computes the temporal evolution of the non-linear vertical salinity profile (based on Cox and Weeks). The energy conserving sea-ice thermodynamic model has one layer of snow on top of several layers of sea ice, with thermal properties depending on salinity and temperature in order to take into account the thermal damping effect of brine pockets on heat transfer in the ice. The model is run with each of the three parameterizations, with NCEP-NCAR atmospheric forcing coming from two regions of the Arctic area. These two regions respectively correspond to FY and MY ice types. Salinity bulk values and profiles are compared with available observations, and impact on the thermodynamic characteristics of the ice is assessed. The analysis show that 1) parameterization (1) cannot reproduce intense desalination in summer and leads to an excessive ice thickness through overestimated surface thermal inertia in summer; 2) bulk salinities simulated by (2) are in agreement with observations, with rapid desalination for FY ice due to intense initial drainage, and a MY ice seasonal cycle, and; (3) if the scope of a study does not go beyond ice thickness and temperature profile in the ice , then, (3) does not improve the simulation compared to (2).
DE: 4207 Arctic and Antarctic oceanography
DE: 4255 Numerical modeling
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting