Here, tectonic drift is compared with the convection rolls. The arrows do not show correct directions, only latitudinal trend. It is the first step to understand the relationship between large scale convection rolls and drift of the tectonic plates.
The difference between North and South Hemisphere, and the relative inactivity of Indian Ocean Ridge, should be studied specially.
This has to be compared to real drift vectors, shown here:
The consistency between both ridges and trenches on one hand and the convection rolls on the other hand can easily be seen. What becomes more difficult for us, is seeing how the system will develop as tectonic drift goes on, when it all looks fixed and we see the consistency between mantle currents and plate tectonics. It looks like if we move something, things would not fit any more! Still, it should become easier in the end, simply because these convection currents move the continents continually around.