HR: 0800h
AN: OS41A-0474    [Abstracts]
TI: Observed and modeled evolution of the deep water properties in the Nordic seas and the Arctic Ocean since the middle of the 20th century
AU: * Spieler, A
EM: spieler@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, 61 Rt 9W, Palisades, NY 07450 United States
AU: Schlosser, P
EM: schlosser@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, 61 Rt 9W, Palisades, NY 07450 United States
AU: Schlosser, P
EM: schlosser@ldeo.columbia.edu
AF: Department of Earth and Environmental Engineering, Columbia University, New York City, NY 10027 United States
AU: Schlosser, P
EM: schlosser@ldeo.columbia.edu
AF: Department of Earth and Environmental Sciences, Columbia University, New York City, NY 10027 United States
AU: Karstensen, J
AF: Forschungsbereich Marine Biogeochemie Institut fr Meereskunde an der Universit„t Kiel , Dsternbrooker Weg 20, Kiel, D-24105 Germany
AU: Newton, B
EM: bnewton@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, 61 Rt 9W, Palisades, NY 07450 United States
AU: Bullister, J
AF: Pacific Marine Environmental Laboratory, NOAA /R/PMEL 7600 Sand Point Way NE , Seattle, Wa 98115 United States
AU: Wallace, D
AF: Forschungsbereich Marine Biogeochemie Institut fr Meereskunde an der Universit„t Kiel , Dsternbrooker Weg 20, Kiel, D-24105 Germany
AU: Blindheim, J
AF: Institute of Marine Research, P.O. Box 1870, Nordnes, Bergen, 5817 Norway
AB: Observations of hydrographic properties and transient tracer distributions during the past few decades revealed a remarkable decrease in the formation rate of Greenland Sea Deep Water (GSDW). On the basis of simple time-dependent mass balance calculations (box models) it has been concluded that this reduction in GSDW production by roughly 80 percent occurred rapidly at around 1980 (+-2 years). Further observations revealed that the change in GSDW production led to reorganizations in the circulation and exchange of deep waters in the coupled system of the GIN seas and the Arctic Ocean. This in turn resulted in significant changes in deep water properties, moving the T/S characteristics of the waters found in the deep Greenland Sea (below ca. 1500 to 2000 meters depth) outside the classical definition of GSDW. Although many studies have addressed the reason for the change in GSDW formation no conclusive answer has been found. In this contribution we address the further evolution of the deep waters in the Nordic seas using hydrographic and transient tracer data, in conjunction with simple box model simulations. We derive deep water formation and exchange rates for the past decade to extend previous work, which used data collected through the mid 1990's. Additionally, we project the evolution of the deep water characteristics under a variety of scenarios for the deep water formation rate in the Greenland Sea.
DE: 4808 Chemical tracers
DE: 4820 Gases
DE: 4532 General circulation
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting