HR: 11:35h
AN: PP22A-06    [Abstracts]
TI: Effects of Surface Freshwater Fluxes on the Ocean General Circulation: A Theoretical Perspective
AU: * Marchal, O
EM: omarchal@whoi.edu
AF: Woods Hole Oceanographic Institution, Quissett Campus, Clark, room 109A, Woods Hole, MA 02543 United States
AB: The changes in ocean circulation that are inferred from paleoclimate records are frequently ascribed to changes in the density of surface waters at high latitudes arising from anomalies in surface freshwater fluxes. This hypothesis is in apparent contradiction with two "theorems" based on the equations of fluid dynamics: the theorem of Sandstrom (1908) and the theorem of Paparella and Young (2002). The theorem of Sandstrom states that the supply and removal of buoyancy at the surface cannot drive the ocean general circulation. Previous attempts to formalize the argument are based on the equation for the circulation of the vector velocity round a material line. The theorem of Paparella and Young implies that a hypothetical ocean forced only by a buoyancy difference at the surface would not exhibit the observed levels of kinetic energy dissipation (as inferred from microstructure observations); other energy sources must be responsible for the flux of kinetic energy in the ocean. Unlike the Sandstrom theorem the theorem of Paparella and Young is based on the full set of the equations of motion (in the Boussinesq approximation) and could be viewed as a more robust statement. Both theoretical arguments suggest that surface buoyancy fluxes constitute an ineffective mechanism for supplying energy to the ocean general circulation. In our presentation we will discuss the strengths and limitations of both arguments and attempt to clarify their paleoclimate implications.
DE: 3344 Paleoclimatology
DE: 4267 Paleoceanography
DE: 1836 Hydrologic budget (1655)
DE: 1600 GLOBAL CHANGE (New category)
DE: 1620 Climate dynamics (3309)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting