Winds & Air Pressure
What causes wind to blow?
Differences in air pressure caused by uneven heating of Earth’s surface
Warm air rises, cool air sinks. This movement of air due to density differences is called what?
Convection
What winds blow between the equator and 30° latitude?
Trade winds
What are streamlike movements of water at or near the surface called?
Surface currents
What two factors affect the density of ocean water?
Temperature and salinity
Air particles that are cooler are more ______ and create areas of ______ pressure
Dense; high
What is a convection cell?
A cyclic pattern of rising warm air and sinking cool air
Which winds blow between 30° and 60° latitude?
Westerlies
What three factors influence surface currents?
Global winds, continental deflection, and the Coriolis effect
Does colder water sink or rise in the ocean?
Sink, because it is denser
Air pressure is the force of air ______ on an object.
Pushing
Earth’s rotation causes moving air to curve instead of flowing straight. What is this called?
The Coriolis Effect
What are the weak wind areas near the equator called?
The doldrums
What is the circular flow of surface currents called?
Gyres
When ocean water freezes, what happens to its salinity?
Salinity increases because salt is left behind in the liquid water
Why does air over land heat up and cool down faster than air over water?
Land changes temperature more quickly than water, so the air above it changes faster
In which direction do winds curve in the Northern Hemisphere due to the Coriolis Effect?
To the right
What high-pressure zones around 30° latitude are associated with many deserts?
The horse latitudes
Do surface currents generally flow in the same direction or opposite direction as global winds?
The same direction
What is the term for the movement of water in regular patterns below the surface?
Deep ocean currents
What two factors combine to create global wind patterns?
Uneven heating of Earth’s surface and Earth’s rotation (Coriolis effect)
Without Earth’s rotation, how would global wind circulation look?
One large convection cell from pole to equator in each hemisphere
Which winds blow near the poles at latitudes above 60°?
Polar easterlies
How do surface currents affect the climate of nearby land?
Warm currents make nearby land warmer; cold currents make it cooler
Together, surface and deep ocean currents form one global circulation system sometimes called what?
The “global conveyor belt” of ocean circulation