A modeling study of Pacific thermocline circulation using Delta(14)C and idealized tracers.

摘要

An ocean model is used in conjunction with tracer and hydrographic data to study the wind-driven circulation of the upper Pacific Ocean. The introductory chapter provides a descriptive overview of the physical and tracer oceanography for the upper Pacific Ocean.;The second chapter consists of a process study focusing on the dynamical mechanisms responsible for the significantly large seasonal sea surface Δ 14C variability recorded by corals during the 1970s and 1980s. It is shown that the variability in Δ14C is primarily due to variability in sea surface currents.;The third chapter consists of a modeling study which considers the sensitivity of equatorial thermocline ventilation to the strength of the Indonesian Throughflow. It is shown that the mixing ratio of northern to southern component water in the equatorial thermocline is quite sensitive to the model's Indonesian Throughflow transport.;The fourth chapter focuses on the model's representation of surface heat fluxes in the extratropical North Pacific Ocean. A parameterization for storm tracks has been included in the atmospheric mixed layer model, and both the modeled SST and thermocline ventilation rates are shown to be quite sensitive to the parameterization.;The fifth chapter describes a simulation of the bomb-Δ14 C transient for the Pacific Ocean. Tracer initialization occurs in 1955 at the onset of hydrogen bomb testing in the atmosphere, and the model is integrated through 1990. It is found that the model does very well in representing the basin-scale inventories of bomb-14C when compared with observations.;The sixth and concluding chapter includes a synthesis of what has been learned, and some potential implications for our understanding of climate variability. Future problems and issues related to intergyre and interbasin exchange for the Pacific Ocean are discussed.