Finite element solutions of the barotropic vorticity equation: Applications to the North Atlantic and North Pacific

A diagnostic, finite element, barotropic ocean model is developed and used to simulate the mean circulation in the North Atlantic. With the inclusion of the joint effect of baroclinicity and relief (JEBAR), the Gulf Stream is found to separate at the correct latitude, ;Examination of results from the World Ocean Circulation Experiment-Community Modelling Effort (WOCE-CME) indicates that the bottom pressure torque component of JEBAR is underestimated by almost an order of magnitude, when compared to the diagnostic results. The reason for this is unclear, but may be associated with the diffuse nature of the modelled thermocline in the CME as suggested by the diagnostic model's sensitivity to the density field above ;The finite element diagnostic model is then used to study the circulation of the North Pacific Ocean. Once more, with the inclusion of the JEBAR term, the model produces a very realistic picture of the circulation. All major currents are reproduced with the calculated transports agreeing well with the observations. The three dimensional velocity structure is also diagnosed and compared with a number of observational sections.;The effect of using different wind stress climatologies in the North Pacific Ocean is also examined. Due to the dominance of the JEBAR term in the solution, the resulting circulations are all similar. Analysis of the seasonal cycle in the model supports the suggestion of Sakamoto and Yamagata the JEBAR rectification can explain the decreased amplitude of the seasonal cycle and the out of phase relationship between observations and the predictions of flat-bottomed Sverdrup theory. Finally, density fields from 1955-1959 and 1970-1974 are used to examine aspects of interpentadal variability in the North Pacific Ocean.