HR: 1340h
AN: C33B-1123    [Abstracts]
TI: Heat and Mass Transfer Laws for Turbulent Convective Flows in the Atmosphere over Leads in Ice Covered Oceans
AU: * Zilitinkevich, S
EM: Sergej.Zilitinkevich@fmi.fi
AF: Division of Atmospheric Sciences, Department of Physical Sciences, University of Helsinki, Vourikatu 15 A, P.O. Box 503, Helsinki, 00101 Finland
AU: * Zilitinkevich, S
EM: Sergej.Zilitinkevich@fmi.fi
AF: 2Nansen Environmental and Remote Sensing Centre / Bjerknes Centre for Climate Research, Thormohlensgate 47, Bergen, 5006 Norway
AU: Esau, I
EM: igore@nersc.no
AF: 2Nansen Environmental and Remote Sensing Centre / Bjerknes Centre for Climate Research, Thormohlensgate 47, Bergen, 5006 Norway
AB: Patches of open water (cracks, leads and polynias) in the ice cover give major contributions to turbulent exchanges of heat, moisture, CO2 and other gases and strongly affect the exchange of momentum between the atmosphere and Polar oceans. In this paper, convective-wind flows over leads are investigated through scaling analyses, analytical solutions to the convective boundary layer equations, and numerical large-eddy simulation (LES) - to estimate basic parameters of turbulence, namely, typical convective-wind velocities, depths-scales of convective zones, horizontal extension of circulations and turbulent fluxes at the air-water interface. The model allowed deriving a heat/mass transfer law, which expresses analytically the turbulent fluxes of heat and water vapour from the water surface to the atmosphere through external parameters: the temperature difference between the open water and the ambient air over surrounding ice, and the static stability in the basic-state atmospheric environment. An important role of the lead width is disclosed: with increasing widths, the efficiency of the heat/mass transfer first increases and, after achieving a maximum, decreases. Theoretical predictions are validated using the LES database of the Nansen Environmental and remote Sensing Centre (NERSC). The proposed model provides grounds for improved parameterization of the air-sea interaction processes in Polar Regions.
DE: 3307 Boundary layer processes
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 3349 Polar meteorology
DE: 3367 Theoretical modeling
DE: 3379 Turbulence (4490)
SC: Cryosphere [C]
MN: Fall Meeting 2005