Mozambique Channel eddies in GCMs: A question of resolution and slippage

作者：Quartly G D^*; de Cuevas B A; Coward A C

来源：Ocean Modelling, 2013, 63: 56-67.

DOI：10.1016/j.ocemod.2012.12.011

• Indian Ocean
• Mozambique Channel
• NEMO
• Spatial resolution
• Boundary conditions
• Stability
• Natal Pulse (current meandering)

Hydrographic observations in the 21st century have shown that the flow within the Mozambique Channel is best described by a series of large poleward-propagating anticyclonic eddies, rather than, as previously thought, a continuous intense western boundary current. The portrayal of this region in various runs of the NEMO 75-level model is found to vary between those two descriptions depending upon the resolution used and the implementation of the model's lateral boundary conditions. In a comparison of 1/4 degrees resolution runs, the change of these conditions from free-slip to no-slip leads to the mean southward flow moving further offshore, with greater variability in the zonal and meridional velocities as the flow organises itself into eddies, and a reduction in total transport. If a realization of a model is unable to get these aspects of the physical flow correct, then this will significantly reduce its ability to show a realistic biological signal or long-term response to climate change. Further south, beyond Durban, the application of no-slip conditions similarly causes the mean Agulhas Current to lie further offshore, making it much more able to simulate Natal Pulses.

• 出版日期2013-3