Answer:
1. Frictional forces
2. Coriolis effect
3. Ekman transport
Step-by-step explanation:
When the wind blows, friction occurs between the air and the water layer. This frictional force is supposed to move the water parallel (in the same direction) to the wind. However, as the earth rotates, it causes an apparent force that affects the motion of all objects within the earth. This Coriolis effect also tends to affect the water body and create current even to a depth of 50-100 meters.
Now, we there have to be a balance between the drag forces caused by friction and the movement of the water body caused by Coriolis effect. This is where Ekman transport comes into play. It determines the final motion of the water body. The water usually move perpendicular to wind direction.