HR: 0830h
AN: OS21C-1134    [PDF]
TI: Modelling changes in the North Atlantic caused by long-term variability in freshwater input
AU: * Yashayaev, I
EM: yashayaevi@mar.dfo-mpo.gc.ca
AF: Bedford Institute of Oceanography, 1 Challenger Drive, P.O.Box 1006,, Dartmouth, NS B2Y 4A2 Canada
AU: Lu, Y
EM: luy@mar.dfo-mpo.gc.ca
AF: Bedford Institute of Oceanography, 1 Challenger Drive, P.O.Box 1006,, Dartmouth, NS B2Y 4A2 Canada
AU: Wright, D
EM: wrightdg@mar.dfo-mpo.gc.ca
AF: Bedford Institute of Oceanography, 1 Challenger Drive, P.O.Box 1006,, Dartmouth, NS B2Y 4A2 Canada
AB: Our recent studies have revealed a large scale freshening in the North Atlantic since the 1960s and documented the contemporaneous changes in the density stratification in the intermediate, deep and bottom waters. Through the 1990s the intermediate layers became denser due to an increase in winter convection in the Labrador Sea, while the deep and bottom waters became less dense due to freshening. There was also a notable increase in fresh water transport along the Labrador shelf (by at least 20%). To investigate the causes and impacts of these large changes in the hygrographic characteristics, we conduct a series of sensitivity experiments using a coarse-resolution North Atlantic model. The model is forced by NCEP/NCAR reanalysis surface flux products and inter-annual variations in T-S properties in the upper layer of the Labrador Sea and in the overflow region derived from the hydrographic data. We examine the ability of the model to reproduce long-term changes in temperature and salinity consistent with observed signals. The model solution also shows interannual variations in ocean meridional circulation. Sensitivity experiments are analyzed for better understanding of the dynamics connecting the long-term changes in circulation and hydrography.
DE: 1635 Oceans (4203)
DE: 1655 Water cycles (1836)
DE: 1836 Hydrologic budget (1655)
DE: 3309 Climatology (1620)
DE: 4215 Climate and interannual variability (3309)
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting