A comparison between the FRAM (Fine Resolution Antarctic Model) results and observations in the Drake Passage

The velocity and density fields generated by the Fine Resolution Antarctic Model (FRAM) are compared with observations made in the neighbourhood of the Drake Passage. Detailed comparisons are presented for the jets along the Subantarctic Front, the Polar Front and the Continental Water Boundary. As the position of the Antarctic Circumpolar Current is mainly topographically controlled, the consequences of smoothing the topography in numerical models are discussed. The transport through the Drake Passage in FRAM is about 180 Sv, about 50 Sv higher than the most recent observations. Reasons for this discrepancy between observations and primitive equation models are discussed. The smoothed topography has forced the Polar Front to divide and merge with the Subantarctic Front and the Continental Water Boundary Front, but cold core current rings are still shed from the Polar Front meander as in the observations.