Two things then happen. The dense water pushes deeper water out of its way and that water moves along the bottom of the ocean. This deep water mixes with less dense water as it flows. Surface currents move water into the space vacated at the surface where the dense water sank Figure below.
Water also sinks into the deep ocean off of Antarctica. Cold water blue lines sinks in the North Atlantic, flows along the bottom of the ocean and upwells in the Pacific or Indian. The water then travels in surface currents red lines back to the North Atlantic.
Deep water also forms off of Antarctica. Since unlimited amounts of water cannot sink to the bottom of the ocean, water must rise from the deep ocean to the surface somewhere.
This process is called upwelling Figure below. Upwelling forces denser water from below to take the place of less dense water at the surface that is pushed away by the wind. Generally, upwelling occurs along the coast when wind blows water strongly away from the shore.
This leaves a void that is filled by deep water that rises to the surface. Upwelling is extremely important where it occurs. During its time on the bottom, the cold deep water has collected nutrients that have fallen down through the water column. Upwelling brings those nutrients to the surface.
Those nutrient support the growth of plankton and form the base of a rich ecosystem. Upwelling also takes place along the equator between the North and South Equatorial Currents.
Winds blow the surface water north and south of the equator so deep water undergoes upwelling. The nutrients rise to the surface and support a great deal of life in the equatorial oceans.
Skip to main content. The Ocean. Search for:. That warms the air, causing it to rise. Cooler air rushes in from the ocean to take its place and presto, a wind is born. By late afternoon, a strong breeze can be blowing dozens of miles inland. A similar effect can occur near big lakes, where the wind is referred to as a lake breeze. Land breezes come at night, when inland temperatures drop enough that the ocean is now warmer than the land, reversing the effect.
Similar forces produce global wind patterns that affect climate. The tropics, for example, are always hot. Air rises here and spreads north and south, high above the land. Lower down, air is pulled in from the north and south. The coriolis effect , an offshoot of the Earth's rotation, makes moving air masses curve, so that the winds converging on the Equator come from the northeast in the Northern Hemisphere and the southeast in the Southern Hemisphere. These winds are called the trade winds. Farther from the Equator, the surface winds try to blow toward the Poles, but the coriolis effect bends them the opposite direction, creating westerlies.
This is why so many weather events in the United States come from the west. Within the mid-latitudes, weather effects create high- and low-pressure zones, called highs and lows , respectively. This apparent deflection is the Coriolis effect. Fluids traveling across large areas, such as air currents, are like the path of the ball. They appear to bend to the right in the Northern Hemisphere. The Coriolis effect behaves the opposite way in the Southern Hemisphere , where currents appear to bend to the left.
The impact of the Coriolis effect is dependent on velocity —the velocity of Earth and the velocity of the object or fluid being deflected by the Coriolis effect.
The impact of the Coriolis effect is most significant with high speeds or long distances. The development of weather patterns, such as cyclones and trade winds, are examples of the impact of the Coriolis effect.
As air masses are pulled into cyclones from all directions, they are deflected, and the storm system—a hurricane —seems to rotate counter-clockwise. In the Southern Hemisphere, currents are deflected to the left.
As a result, storm systems seem to rotate clockwise. Outside storm systems, the impact of the Coriolis effect helps define regular wind patterns around the globe. As warm air rises near the Equator, for instance, it flows toward the poles. In the Northern Hemisphere, these warm air currents are deflected to the right east as they move northward.
As the current descends, it gradually moves from the northeast to the southwest, back toward the Equator. The consistently circulating patterns of these air masses are known as trade winds. The weather impacting fast-moving objects, such as airplanes and rockets, is influenced by the Coriolis effect. The directions of prevailing winds are largely determined by the Coriolis effect, and pilots must take that into account when charting flight paths over long distances.
Military snipers sometimes have to consider the Coriolis effect. The Earth rotates fairly slowly, compared to other known planets. The slow rotation of Earth means the Coriolis effect is not strong enough to be seen at slow speeds over short distances, such as the draining of water in a bathtub. Jupiter , on the other hand, has the fastest rotation in the solar system.
On Jupiter, the Coriolis effect actually transforms north-south winds into east-west winds, some traveling more than kilometers miles per hour. The boundaries between these fast-moving belts are incredibly active storm regions. The year-old Great Red Spot is perhaps the most famous of these storms. Despite the popular urban legend , you cannot observe the Coriolis effect by watching a toilet flush or a swimming pool drain.
You can observe the Coriolis effect without access to satellite imagery of hurricanes, however. You could observe the Coriolis effect if you and some friends sat on a rotating merry-go-round and threw or rolled a ball back and forth.
When the merry-go-round is not rotating, rolling the ball back-and-forth is simple and straightforward. Rolled with regular effort, the ball appears to curve, or deflect, to the right. Actually, the ball is traveling in a straight line. Another friend, standing on the ground near the merry-go-round, will be able to tell you this. You and your friends on the merry-go-round are moving out of the path of the ball while it is in the air.
In the southern hemisphere, winds appear to curve to the left. This is known as the Coriolis effect, which is the apparent shift in the path of any fluid or object moving about the surface of the Earth due to the rotation of the Earth. Near the equator, the trade winds converge into a broad east to west area of light winds.
The area is known as the doldrums because there are light winds. This area is known as the intertropical convergence zone ITCZ , and is the area with the most active weather.
As you learned the Northern Hemisphere has more landmass and is relatively warmer than the Southern Hemisphere. Also at the equator, warmer, moist air rises and produces a low-pressure area extending many kilometers north and south of the equator.
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