What causes atmospheric

currents?

The atmosphere and water are both fluids and behave in similar ways.

Stores the Sun’s energy◦ Helps maintain stable temperatures on Earth

Stores CO2

Provides O2

Provides H2O Important part of the food chain

The Ocean

Ocean Currents

Surface currents Deep currents

Two types of ocean currents

Caused by winds. Friction causes water to be dragged along

with the wind.

Surface currents

The winds in the atmosphere curve due to the Coriolis Effect, so…

The surface currents curve also. These circular wind patterns create spiral

ocean currents called gyres

Surface currents

Gyres

A particularly strong current that is part of the North Atlantic gyre, carries warm water from the Gulf of Mexico up the coast of the eastern United States and over to western Europe.

Gulf Stream

The warmer water warms the air, raising the temperature.

This especially powerful current is 149 miles (240 kilometers) wide and almost 1 mile (1.6) kilometers deep and can move up to 26 billion gallons of water a second. That's more than the flow of the Amazon River!

The current has caused so many shipwrecks around Cape Hatteras, a piece of land that juts out sharply from the east coast of North Carolina, that the area is called the graveyard of the Atlantic.

Gulf Stream

Great Pacific Garbage Patch

Powered by gravity More dense ocean water sinks What factors cause ocean water to become

more dense? 1. Temperature (thermo) 2. Salt content (haline)

Deep ocean currents

Colder water is more dense. But… When water freezes it becomes less dense. That’s why ice floats

Temperature

Uneven heating of the water’s surface Uneven heating at different depths Why?

◦ Sun’s rays don’t penetrate deep into the ocean

What causes water temperature to change?

Salinity – salt concentration

Haline

Weathering of rocks continually adds sodium to the Earth’s rivers and subsequently to the ocean.

Where does the salt come from?

Freezing of water and the melting of ice

What causes changes in salinity?

Sea ice is ocean water that freezes Glaciers form on land and contain fresh

water

Side note

When ocean water freezes the salt is left behind.

This causes the salinity of the water to increase and its density to increase.

Freezing

When sea ice or glaciers melt (fresh water) the salinity of the surrounding water decreases.

Melting

Large scale ocean circulation that is driven by differences in ocean water density.

Thermohaline circulation

Surface and deep current interaction

Deeper currents travel much slower than surface currents.

Surface currents ~2meters per second Deep currents ~10 cm per second

Speed

Physical features in the ocean redirect currents.

Currents flow to the deepest part of the ocean.

Topography

Currents redistribute heat from low latitudes (equator) to high latitudes(poles).

Currents influence the ocean temperature, weather, and climate.

Currents transport nutrients around the ocean.

Impact