Question

What are surface currents caused by

Answer 1

The amount of wind seems like the most possible cause for surface currents.  I believe temperature has a little something to do with it as well.  Fill a clear dish with water and gently blow.  You'll notice waves.  Try blowing across it a second time with a little more force.  You'll see even bigger waves.  Vibrations in the earth also can contribute to waves....earthquakes or any kind of seismic activity can cause surface currents as well.