Bottom topography and oceanic variability - Joe LaCasce (U. Oslo)

Date & time

2–3pm 2 October 2018


Hales Room, J7


Joe LaCasce


 Taimoor Sohail

Many fundamental theories of ocean circulation
neglect bottom topography. Indeed, flat bottom ocean basins are
still used today to study a range of phenomena. Here we examine
evidence that the bottom affects eddies throughout the water 
column. Current meter data point to the existence of a mode 
of variability which is largest at the surface and decreases to
near zero at the bottom. We show that the gravest baroclinic mode
has a similar shape, even with very weak bottom variations. Then
we examine how topography affects ocean jets, like the Antarctic
Circumpolar Current. Having relatively modest bottom bumps
can stabilize baroclinic instability, favoring lateral (barotropic)
instability instead. Taken together, the results suggest topography
exerts an important influence on variability, and thus that flat bottom 
models may be misleading. 

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