Evaluation of Interior Circulation in a High-Resolution Global Ocean Model. Part I:

• Main Authors: Bottom Waters, Alexander Sen, Gupta, Matthew H. England
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2003
• Subjects: Antarctic; The Antarctic; Antarc*; Labrador Sea
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.685.1491; http://web.science.unsw.edu.au/%7Ematthew/sge_jpo04.pdf

Global watermass ventilation pathways and time scales are investigated using an ‘‘eddy permitting’ ’ (8) offline tracer model. Unlike previous Lagrangian trajectory studies, here an offline model based on a complete tracer equation that includes three-dimensional advection and mixing is employed. In doing so, the authors are able to meaningfully simulate chlorofluorocarbon (CFC) uptake and assess model skill against observation. This is the first time an eddy-permitting model has been subjected to such an assessment of interior ocean ventilation. The offline model is forced by seasonally varying prescribed velocity, temperature, and salinity fields of a state-of-the-art ocean general circulation model. A seasonally varying mixed layer parameterization is incorporated to account for the degradation of surface convection processes resulting from the temporal averaging. A series of CFC simulations are assessed against observations to investigate interdecadal-time-scale ventilation using a variety of mixed layer criteria. Simulated tracer inventories and penetration depths are in good agreement with observations, especially for thermocline, mode, and surface waters. Deep water from the Labrador Sea is well represented, forming a distinct deep western boundary current that branches at the equator, although concen-trations are lower than observed. The formation of bottom water, which occurs around the Antarctic margin, is also generally too weak, although there is excellent qualitative agreement with observations in the region of the