Major Boundary Currents and Inter-basin Flows
How will the key science questions be addressed?
How are climate-change-related variations in the global circulation of momentum, heat, salt and nutrients modulated by the Australian gyre connection?
How do the two Pacific-Indian throughflow components vary temporally?
These components will be monitored by the Indonesian Throughflow (ITF) array (in conjunction with additional moorings in the other Indonesian straits) and the proposed Tasmanian Outflow (TO) array. Supporting measurements come from XBT sections for the ITF and the L'Astrolabe XBT section and Glider transects at the SOTS mooring will provide additional coverage of the TO flow.
How does the time-varying flow of the ITF influence the Leeuwin Current (LC) and the southwestern Australian shelf?
The ITF array observes the ITF signal within the Timor Strait and across the shelf that feeds into the LC and the southwestern Australian waveguide. Downstream, the glider deployments in the LC and coastal moorings (WAIMOS and SAIMOS) should resolve the local effects.
How do the mass and heat transport of each of the components of the Australian boundary system vary on timescales from interannnual, to multi-decadal?
The EAC is monitored by the Brisbane array, the TO by the next stage array and the glider transects, the Hirri Current by glider transects, the LC by glider transects and the next stage array and the Flinders Current by both the next stage LC and TO arrays. The Tasman Box, Fremantle- Singapore and l'Astrolabe XBT sections and Argo floats provide the broad interior flow in which the boundary currents are imbedded.
What are the dynamics associated with the temporal changes in the South Equatorial Current bifurcation location?
What controls the EAC separation?
The large scale context of the separation will be monitored by the EAC array, the Tasman Box XBTs, and satellite altimetry. More local aspects of the separation processes come from glider transects, Argo, coastal moorings and surface drifters.
How is the EAC partitioning between the Tasman Front and EAC Extension varying over time?
What is the formation mechanism of EAC eddies, how are they related to the mean flow and how does eddy field vary temporally?
The Tasman Box XBT sections and satellite altimetry observations provide time series of the largescale structure of the eddy field. The EAC array is located in a likely formation region of the EAC eddies. Glider sections provide high-resolution structure within warm-core and cold-core eddies.
What are the temporal changes in the advective and air-sea components of the EAC, and LC heat flux distributions?
The advective component of heat flux is determined by the Tasman Box XBTs, the EAC array and satellite altimetry. The interior heat storage is monitored by the Argo array. Improved meteorological observations from SOOP will feed into improved air-sea flux products.
What forcing mechanisms drive the seasonal cycles of the EAC and LC?
The Tasman Box XBTs, the EAC Brisbane array (for the EAC), the next stage Leeuwin Current array (for the LC), glider transects, Argo floats and satellite observations enable the seasonal cycle to be documented and possible sources to be explored.
What are the underlying dynamics of the Holloway Current and how is it related to the LC?