Wind and Waves: Surface Ocean Currents Explained Quiz

The Sun heats the Earth unevenly. Warm air at the equator rises and moves toward the poles, creating wind. As wind blows across the ocean, it pulls the top layer of water along with it through friction.

Because the Earth rotates, the paths of winds and currents are deflected. This is known as the Coriolis Effect. In the Northern Hemisphere, they curve to the right; in the Southern Hemisphere, they curve to the left.

There are five major gyres on Earth. These act like giant conveyor belts that move heat around the planet, keeping some coastlines warmer or cooler than they would otherwise be.

Surface currents only go about 400 meters deep. They are steered by winds and the "walls" created by continents. The Coriolis Effect ensures they maintain a circular pattern.

The Gulf Stream acts like a giant heater. It carries warm water from the Gulf of Mexico toward Western Europe, which is why London has much milder winters than similar latitudes in Canada.

These steady winds are responsible for pushing warm surface water toward the west. This buildup of warm water is a key factor in global weather patterns.

Imagine trying to draw a straight line on a spinning record player; the line will end up curved. The same thing happens to water and air moving across our rotating planet.

Western boundary currents are the "express lanes" of the ocean gyres. They move quickly along the eastern coasts of continents, transporting tropical heat toward the poles.

Continents act like barriers. When a current moving west hits a landmass, it is forced to turn north or south, which helps complete the circular loop of an ocean gyre.

Even though they are the most famous currents, they only represent the top layer. The other 90% of the ocean moves in much slower, deeper patterns driven by density (salt and temperature).

The Westerlies drive the top half of the gyres in the Northern Hemisphere, pushing water back toward Europe and the west coast of North America.

Air takes on the temperature of the water below it. Cold water cools the air and can create fog, while warm water provides the moisture and heat needed for rain.

Due to the Coriolis Effect, the circular flow in the North Pacific and North Atlantic moves in a clockwise direction. In the Southern Hemisphere, this pattern is reversed.

Because the water at the center of a gyre is very calm, plastic and debris that get caught in the rotating currents eventually drift inward and get trapped.

This is common on the west coasts of continents. As wind pushes surface water away, cold, nutrient-rich water rises to take its place, creating excellent fishing grounds.