Scotia Sea pathways as deduced from Argo floats

• Main Authors: Olivé Abelló, Anna, Pelegrí, Josep Lluís
• Format: Conference Object
• Language: English
• Published: 2019
• Subjects: Argo floats; Scotia Sea; Antarctic Circumpolar Current; Antarctic; Drake Passage; North Scotia Ridge; The Antarctic; Antarc*
• Online Access: http://hdl.handle.net/10261/199714

7th Euro-Argo Science Meeting, 22-23 October 2019, Athens, Greece We use the Argo floats database to quantify the water transports of the Antarctic Circumpolar Current (ACC) through the Scotia Sea in the upper 2000 m of the water column. The reference velocities are calculated from the speed of the floats at the 1000-m parking depth and the relative geostrophic velocities are calculated from the float profiles nearby the selected sections. After removal of all floats deployed too close to the Drake Passage, the number of floats crossing each passage correlates well with the transports, and the individual trajectories allow identifying the preferred pathways. Considering the entire database till October 2018, we identify a total of 253 floats drifting through the Drake Passage with 214 of them following through the North Scotia Ridge passages. This allows reconstructing the vertical hydrographic structure at 25-km resolution from the sea surface to 2000 m. Our results indicate a geostrophic transport of 174.0 Sv in the Drake Passage, with a barotropic component of 114.1 Sv and a baroclinic component of 59.9 Sv, while in the North Scotia Ridge passages the total transport is 192.8 Sv, with a barotropic component of 107.9 Sv and a baroclinic component of 84.9 Sv. Most transport through the Drake and North Scotia Ridge Passages comes from jets associated with the Subantarctic and Polar Fronts, and to a lesser degree the Southern ACC Front. The amount of data is enough to explore the inter-annual variations (through a 5-yr running filter), which illustrates the existence of substantial changes, up to 45.5 Sv through the Drake Passage Peer reviewed