Coriolis effect

The picture at the top shows an inert frame of reference, where the black object moves in a straight line. In the picture at the bottom the observer(red dot) sees the object follow a curved path, because of the Coriolis and Centrifugal effects

This low pressure system over Iceland spins counter-clockwise due to balance between the Coriolis force and the pressure gradient force.

The Coriolis effect is a force that is found in a rotating object. Gaspard Gustave de Coriolis first described the Coriolis effect in 1835 using mathematics. It is a fictitious force that acts upon all bodies which are described using a rotating frame of reference. The force is perpendicular to both the axis of movement of the body it acts on as well as that of the frame of reference. .