Steady-state and transient modeling of tracer and nutrient distributions in the global ocean. Progress report, June 1, 1991--March 31, 1992

• Main Authors: Stocker, T. F., Broecker, W. S.
• Other Authors: United States. Department of Energy.
• Format: Report
• Language: English
• Published: Columbia Univ., Palisades, NY (United States). Lamont-Doherty Geological Observatory 1992
• Subjects: Carbon Cycle; Oceanic Circulation; Sea Bed; Temperature Distribution; Coriolis Force; Seas; Nutrients; Latitude Effect; Carbon 14; Progress Report; Salinity; 58 Geosciences; Geographical Variations; Spatial Distribution; Mathematical Models; Carbon Dioxide 580000; Geosciences; Global Aspects; General Circulation Models; Antarctic; Indian; Pacific; Southern Ocean; Antarc*; North Atlantic Deep Water; North Atlantic
• Online Access: https://doi.org/10.2172/10138991; https://digital.library.unt.edu/ark:/67531/metadc1316565/

The deep circulation model developed by Wright and Stocker has been used to represent the latitude-depth distributions of temperature, salinity, radiocarbon and ``color`` tracers in the Pacific, Atlantic and Indian Oceans. Restoring temperature and salinity to observed surface data the model shows a global thermohaline circulation where deep water is formed in the North Atlantic and in the Southern Ocean. A parameter study reveals that the high-latitude surface salinity determines the composition of deep water and its flow in the global ocean. Increasing Southern Ocean surface salinity by 0.4 ppt the circulation changes from a present-day mode where North Atlantic Deep Water is one where Antarctic Bottom Water is dominant. An inorganic carbon cycle with surface carbonate chemistry is included, and gas exchange is parameterized in terms of pCO{sub 2} differences. Pre- industrial conditions are achieved by adjusting the basin-mean alkalinity. A classical 2{times}CO{sub 2} experiment yields the intrinsic time scales for carbon uptake of the ocean; they agree with those obtained from simple box models or 3-dimensional ocean general circulation models. Using the estimated industrial anthropogenic input of CO{sub 2} into the atmosphere the model requires, consistent with other model studies, an additional carbon flux to match the observed increase of atmospheric pCO{sub 2}. We use more realistic surface boundary conditions which reduce sensitivity to freshwater discharges into the ocean. In a glacial-to-interglacial experiment rapid transitions of the deep circulation between two different states occur in conjunction with a severe reduction of the meridional heat flux and sea surface temperature during peak melting. After the melting the conveyor belt circulation restarts.