Question

What are the subtropical gyres, and what forces them.

Short answer

Subtropical gyres are large ocean current systems driven by global wind patterns and the Coriolis Effect.

Step-by-step solution

Understand Subtropical Gyres

Subtropical gyres are large systems of circular ocean currents formed by global wind patterns and forces created by Earth's rotation. They are found in both the Northern and Southern Hemispheres, located at approximately 30 degrees latitude.

Wind Patterns and Subtropical Gyres

The trade winds and the westerlies are the primary wind patterns that drive the subtropical gyres. The trade winds blow from east to west at the equator, while the westerlies blow from west to east in temperate zones. This creates a convergence of winds in the subtropical regions.

Role of the Coriolis Effect

The Coriolis Effect, which is the deflection of moving objects caused by Earth's rotation, plays a key role in the formation of subtropical gyres. In the Northern Hemisphere, this effect causes currents to veer to the right, while in the Southern Hemisphere, they veer to the left, contributing to the circular flow in these gyres.

The Ocean's Response

The combination of wind patterns and the Coriolis Effect leads to a high-pressure system in the center of a subtropical gyre. The ocean surface in this region is higher than the surrounding areas, causing water to flow outward and initiating a circular current.

Key concepts

Global Wind Patterns

Global wind patterns are like the invisible conveyor belts that push the oceans into their swirling motions. These winds are essential in shaping the behavior of the world's oceans and, in turn, influencing weather and climate.

They originate from the sun's uneven heating of Earth. Because the Earth is a sphere, it receives more solar energy near the equator than at the poles, causing air to circulate in large patterns.

• The trade winds, for example, are steady winds that flow from east to west in the tropics.
• The westerlies blow from west to east in the temperate zones.

These winds, in combination with Earth's rotation, are crucial in driving the subtropical gyres in both hemispheres.

Coriolis Effect

The Coriolis Effect might sound complicated, but it is simply the result of Earth's rotation affecting the movement of objects like air and water. When you imagine the Earth spinning, anything that moves in a straight line across its surface will appear to curve as it travels.

This effect is due to the different rotational speeds at different latitudes. The effect influences weather patterns, ocean currents, and the formation of cyclones.

• In the Northern Hemisphere, moving objects veer to the right.
• In the Southern Hemisphere, they veer to the left.

That deflection is what helps create the circular motion of the ocean currents seen in subtropical gyres.

Ocean Currents

Ocean currents are large volumes of water moving continuously through the world's oceans. They play an important role in distributing heat around the planet, influencing local climates and even marine life habitats.

These currents are driven by several forces: wind, water density differences, and tides. However, the most important for the subtropical gyres are the wind patterns and Coriolis Effect.

The continuous push of winds combined with the Earth's rotation keeps the water cycling in large, looping flows. In the center of these ocean currents, water tends to pile up slightly, creating a dome of higher water levels that aids in keeping the circular motion strong and steady.

Earth's Rotation

Earth's rotation is the underlying force that sets the stage for many dynamic processes on our planet. As Earth spins on its axis, it brings about day and night and influences how atmospheric and oceanic systems behave.

This rotation causes the Coriolis Effect, which is essential for the formation and maintenance of subtropical gyres. Without Earth's rotation, wind patterns and ocean currents would not follow the predictable paths that they currently do.

• The daily rotation results in a slight bulge at the equator, affecting gravity and how water bodies are shaped.
• It also ensures that weather systems, like high and low pressure areas, move in identifiable patterns.

Ultimately, the steady rotation of Earth creates the stable but dynamic environment that sustains the subtropical gyres.