Atmospheric and Oceanic Circulation

Atmospheric and Oceanic Circulation

Middle School

​

Learning Objectives

• Model how the Sun's heating and Earth's rotation create ocean and air currents.

• Explain how temperature and salinity create density differences that drive ocean currents.

• Describe how the Coriolis effect and landforms influence atmospheric and oceanic flow.

• Analyze how the heating of land and water creates different climates.

Key Vocabulary

​

Climate

Climate is the long-term pattern of weather that occurs in a particular area over many years.

​

Convection

Convection is the transfer of thermal energy that happens when fluids, like air or water, move.

​

Coriolis Effect

The Coriolis Effect is the apparent curve of a moving object's path caused by Earth's rotation.

​

Density

Density measures the amount of mass that is packed into a specific, given amount of volume.

​

Salinity

Salinity is the scientific measure of all the dissolved salts that are contained in the water.

​

Thermal Energy

Thermal energy is the type of energy that is generated and comes from a heat source.

Key Vocabulary

​

Prevailing Winds

These are global winds that consistently blow from a single, general direction over a particular point.

​

Surface Current

A surface current is a horizontal movement of ocean water that is primarily caused by wind.

​

Upwelling

Upwelling is the process where deep, cold, and nutrient-rich ocean water rises to the surface.

​

Gyre

A gyre is a large system of circulating ocean currents, often driven by prevailing winds.

​

Ocean Conveyor Belt

This is a global-scale circulation of ocean water that is responsible for redistributing heat energy.

​

Rain Shadow

A rain shadow is a dry area on the leeward, or downwind, side of a mountain.

​

​

How the Sun Creates Wind

• The Sun heats our planet unevenly, which creates different temperature zones.

• The equator receives direct sunlight, making it warm, while the poles are cold.

• Warm air at the equator rises, creating a low-pressure zone.

• The air cools, sinks at the poles, and flows, creating wind.

​

Multiple Choice

What is the primary reason that wind is created on Earth?

• The uneven heating of the planet by the Sun.

• The rotation of the Earth on its axis.

• The gravitational pull of the Moon.

• The movement of clouds in the atmosphere.

Multiple Choice

How does the air at the equator begin the process of creating wind?

• Warm air rises at the equator, creating a low-pressure zone.

• Cold air at the poles rises, creating a high-pressure zone.

• Warm air at the equator sinks, pushing the air away.

• Cold air and warm air mix, which stops all air movement.

Multiple Choice

If the Sun heated the Earth evenly all over, what would be the most likely impact on wind?

• Wind would stop because the main cause of air movement would be gone.

• Wind would become much stronger and more unpredictable.

• Wind would reverse direction, flowing from the poles to the equator.

• Wind would not be affected by the change in temperature.

​

​

Global Winds and the Coriolis Effect

Northern Hemisphere

• ​Due to the Earth's rotation, moving objects like wind appear to curve from their straight path.

• ​​In the Northern Hemisphere, the path of the wind is deflected, curving towards the right.

• ​This rightward deflection is a key factor in shaping large-scale weather systems and ocean currents.

Southern Hemisphere

• ​The Coriolis effect is a result of the Earth's continuous rotation on its own axis.

• ​​In the Southern Hemisphere, this causes the path of the wind to curve towards the left.

• ​This leftward curve influences the rotation of major storms and the circular patterns of ocean gyres.

Multiple Choice

What causes the path of moving objects like wind to appear to curve as they travel across the globe?

• The Earth's rotation on its axis

• The gravitational pull of the Moon

• The changing seasons of the year

• The heat rising from the planet's core

Multiple Choice

How does the Coriolis effect impact wind direction differently in the Northern and Southern Hemispheres?

• The wind curves to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

• The wind curves to the left in the Northern Hemisphere and to the right in the Southern Hemisphere.

• The wind travels in a straight line in the Northern Hemisphere but curves in the Southern Hemisphere.

• The wind's path is only affected over oceans and not over land in both hemispheres.

Multiple Choice

If a large-scale weather system begins to form over the ocean in the Southern Hemisphere, what is the most likely outcome due to the Coriolis effect?

• It would likely start to rotate based on a leftward curve.

• It would likely start to rotate based on a rightward curve.

• It would travel in a straight line without any rotation.

• It would immediately move toward the Northern Hemisphere.

How Geography Shapes Climate

• Land heats and cools faster than water, creating different climate zones.

• As the altitude increases, the average temperature generally gets lower.

• Mountains can block moist air, causing a dry area called a rain shadow.

Multiple Choice

What generally happens to the average temperature as the altitude of a location increases?

• The average temperature gets lower.

• The average temperature gets higher.

• The temperature stays exactly the same.

• The area receives more rainfall.

Multiple Choice

Why might a coastal area have a different climate from an inland area?

• Because land heats and cools faster than water.

• Because there are more mountains near the coast.

• Because the altitude is always higher near water.

• Because ocean water is always cold.

Multiple Choice

A coastal region gets a lot of rain from ocean winds. If a tall mountain range is located just inland from the coast, what would the climate most likely be on the other side of the mountains?

• The area would be dry because the mountains block moist air.

• The area would be very cold because it is far from the water.

• The area would be very rainy because it is on the other side of a mountain.

• The area would have the same climate as the coastal side.

​

​

Ocean Circulation: Surface and Deep Currents

Surface Currents

• Surface currents are primarily driven by wind blowing across the surface of the ocean.

• These currents move ocean water horizontally and are organized into large circular patterns called gyres.

• The direction of these currents is influenced by the Earth’s rotation and the position of continents.

Deep Ocean Currents

• Deep ocean currents are driven by differences in water density, caused by temperature and salinity.

• This process is known as the global ocean convection cycle, which circulates water globally.

• Colder, saltier water is denser and sinks, while warmer, less salty water rises to the surface.

Multiple Choice

What are the two main factors that drive surface and deep ocean currents?

• Wind and differences in water density

• The Moon's gravity and Earth's rotation

• The shape of continents and ocean depth

• Marine animals and underwater volcanoes

Multiple Choice

What is the key difference between how deep ocean currents and surface currents are formed?

• Deep currents are driven by density differences, while surface currents are driven by wind.

• Surface currents create the global ocean convection cycle, while deep currents form gyres.

• Deep currents are caused by Earth's rotation, while surface currents are caused by temperature.

• Surface currents move water vertically, while deep currents move water horizontally.

Multiple Choice

In a polar region, ocean water becomes very cold and its salinity increases as sea ice forms. What is the most likely result of this change?

• The water would become denser and sink, driving a deep ocean current.

• The wind would cause the water to form a large circular gyre.

• The water would become less salty and rise to the surface.

• The current would stop because the water is too cold to move.

​

​

The Global Conveyor Belt and Climate

• The Great Ocean Conveyor Belt links surface and deep ocean currents.

• ​This system acts like a giant loop moving water around the world.

• It helps regulate Earth's climate by redistributing thermal energy globally.

• This movement helps determine regional climates and moderate global temperatures.

Multiple Choice

What is the main function of the Great Ocean Conveyor Belt?

• It creates powerful waves and tsunamis.

• It helps marine animals migrate.

• It redistributes heat around the Earth.

• It causes the ocean's tides to change daily.

Multiple Choice

How does the Great Ocean Conveyor Belt help regulate and determine regional climates?

• By moving warm water from the equator toward the poles.

• By making the water at the poles much saltier.

• By pushing cold water from the poles toward the equator.

• By mixing deep ocean currents with surface currents.

Multiple Choice

Based on its role in the climate system, what would be the most likely consequence if the Great Ocean Conveyor Belt stopped circulating?

• The oceans would become much warmer overall.

• Climates would become more extreme in many regions.

• Sea levels around the world would drop significantly.

• All ocean life would migrate toward the equator.

​

Common Misconceptions

Misconception	Correction
A region's climate is determined only by its latitude.	Climate is also influenced by oceans, altitude, and landforms.
Wind and ocean currents are not related.	Wind is a primary driver of surface ocean currents.
The Coriolis effect is a true force.	It is an apparent effect caused by Earth’s rotation.
Oceans heat up at the same rate as land.	Water absorbs and releases heat much more slowly than land.

​

Summary

• The sun's unequal heating of Earth drives all circulation.

• Atmospheric and oceanic circulation redistributes thermal energy around the globe.

• Earth's rotation and continents create predictable patterns in winds and currents.

• Wind and water density differences drive the Global Ocean Conveyor Belt.

Poll

On a scale of 1-4, how confident are you about explaining how circulation patterns affect regional climate?

• 1 - Not confident at all

• 2 - A little confident

• 3 - Mostly confident

• 4 - Very confident