Simulations of Radiocarbon in a Coarse-Resolution World Ocean Model 2. Distributions of Bomb-Protjuced ' Carbon 14

• Main Author: Ar~d K. Bryan
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; The Antarctic; Antarc*
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.143.6421; http://www.gfdl.noaa.gov/reference/bibliography/1989/jrt8902.pdf

primitive equation ocean general circulation model to simulate the steady state di:,tribution of naturally produced 14C in the ocean prior to the nuclear bomb tests of the 1~150s and early I~s. In part 2 we begin with the steady state distributions of part I and subject the model to the pulse of elevated atmospheric 14C concentrations observed since the 1 950s. This study focuses on the processes and time scales which govern the transient distributions of bomb 14C in the upper kilometer of the ocean. Mode! projections through 1m are compared with observations compiled by th(: Geochemical Ocean Sections Study (GEOSECS) in 1972, 1974, and 1978: the Transient Tracers in the Ocean mO) expedition in 1981, and the French INDIGO expeditions in 1985-1987. In their analysis of the 'GEOSECS 14C observations, Broecker et al. (1985) noted that much of the bomb 14C which entered the ocean's equatorial belts prior to GEOSECS accumulated in the adjacent subtropical zones. Broecker et al. argued that this displacement of bomb 14C inventories was caused by the wind-driven upwelling and surface divl~rgence in the tropics combined with convergent flow and downwelling in the subtropics. Similar displacements were invoked to shift bomb 14C from the Antarctic circumpolar region into the southern temperate 20ne. The GFDL model successfully reproduces the ob!;erved GEOSECS inventories, but then predicts a significantly different pattern of bomb 14C uptake in the decade following GEOSECS. The post-GEOSECS buildup of bomb 14C