Production and analysis of a Southern Ocean state estimate

• Main Author: Mazloff, Matthew R.
• Format: Thesis
• Language: English
• Published: Massachusetts Institute of Technology and Woods Hole Oceanographic Institution 2006
• Subjects: Ocean circulation; Southern Ocean
• Online Access: https://hdl.handle.net/1912/1282

Submitted in partial fulfillment of the requirements for the degree of Master of Science in Physical Oceanography, Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2006 A modern general circulation model of the Southern Ocean with one-sixth of a degree resolution is optimized to the observed ocean in a weighted least squares sense. Convergence toward the state estimate solution is carried out by systematically adjusting the control variables (prescribed atmospheric state, initial conditions, and open northern boundary at 24.7°S) using the adjoint method. A cost function compares the model state to data from CTD synoptic sections, hydrographic climatology, satellite altimetry, and XBTs. Costs attributed to control variable perturbations ensure a physically realistic solution. An optimized solution is determined by the weights placed on the cost function terms. The state estimation procedure, along with the weights used, is described. A significant result is that the adjoint method is shown to work at eddy-permitting resolution in the highly-energetic Southern Ocean. At the time of the writing of this thesis the state estimate was not fully consistent with the observations. An analysis of the remaining misfit, as well as the mass transport in the preliminary state, is presented.