This is the first of two manuscripts dealing with the circulation, mixing, ventilation and organic matter mineralization of the South Atlantic Ocean (SAO). The present work quantifies the complex mixing of water masses in the SAO using a constrained, least-squares regression, Optimum MultiParameter (OMP) analysis. The OMP based on temperature, salinity, silicate and the conservative parameter NO, was applied on two World Ocean Circulation (WOCE) lines, A17 and A14, in the western and eastern SAO, respectively. The constrained OMP sensitivity to sources of error in the end-member characteristics, measured parameters, equation weights and oxygen to nitrogen mineralisation ratio (RN) was carefully assessed using perturbation tests. Perturbation of RN was the... |