A graphic showing wind-driven ice movement
Ascat shows ice movement. It doesn't necessarily have to be wind driven. Fram Strait is a clear example.
Indeed, movement is movement and the causes are not visible from above. But even in the Fram Strait, where we know that there is an underlying south-heading current, the ice movement is strongly influenced by wind, which happens to generally blow in the same direction as the current. But when the wind reverses in the Fram Strait, export stops and can even go in reverse.
John thinks that the tides somehow move vast amounts of water all over the place twice daily. The physics of course is that the tidal effect is caused by expansion of water in the deep ocean at lower latitudes, with minimal actual movement of water except where coastal obstruction creates a local height/gravity imbalance (a fancy way of saying "downward slope").
Anybody who has been at sea knows that the tides have no effect whatsoever on the movement of ships except in coastal waters. But the well known and extensively mapped ocean currents have a very big effect on the movement of ships. What goes for ships goes for other floating things, including sea ice.
Which reminds me of another of my bug-bears: Bathymetry has no effect on the movement of ships unless the depth is a very low multiple of the draft (i.e. 0 - 2). When 0, the ship grounds, and while less than around 2 there is a measurable resistance as the water has reduced freedom of movement away from the hull.
And so bathymetry cannot have any direct influence on the movement of ice. There is no direct causal connection between bathymetry and ice movement and position, unless the depth is within 0-2 times the draft of the individual floes.
