What is wind?

What causes wind?

Winds are caused by differences s in air pressure. Wind is the sideways movement of air and is moved from an area of high pressure to an area of low pressure.

What is wind

Wind is the horizontal movement of air from an area of high pressure to an area of lower pressure.
Sea Breeze vs. Land Breeze
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What are local winds?

Local winds are winds that blow over a short distance.

How are local winds created?

Local winds are created by the unequal heating of Earth's surface within a small area.

  • Unequal heating often happens near lakes and ocean coasts
  • A example of local wind is a cool breeze blowing in from the water over a beach
  • Caused by geographic features that produce temperature differences

How do sea breezes blow?

A sea breeze blows from the ocean.

  • A lake breeze is a local wind that blows from a lake
  • A sea breeze or a lake breeze usually happens during the day
  • The wind blows from the higher pressure over the water to lower pressure over the land
  • The sea breeze strength will vary depending on the temperature difference between the land and the ocean

How do land breezes blow?

  • A land breeze blows from the land over a lake or ocean
  • A land breeze usually happens at night
  • The wind blows from the higher pressure over the water to lower pressure over the land
  • This is because air cools in the nighttime

What are global winds?

A global wind is a wind that blows steadily over a long distance.

  • Global winds blows from the same direction every time
  • These are polar easterlies, prevailing westerlies, and trade winds.

How are global winds created?

  • The combination of pressure belts and the Coriolis Effect cause global winds
  • All wind is caused by the uneven heating of Earth's surface, which sets convection currents in motion
  • Convection currents on a large scale cause global winds; convection currents on a small scale cause local winds.

Horse Lattitudes

• Occur at about 30° north and south of the equator where the winds are very weak

• Most deserts on the Earth are located here because of the dry air

Trade Winds

  • Winds that blow from 30° almost to the equator

  • Called the trade winds because of their use by early sailors

Prevailing Westerlies

  • Wind belts found between 30 and 60 degrees latitude
  • Flow towards the poles from west to east
  • Carries moist air over the United States

Polar Easterlies

  • Wind belts that extend from the poles to 60 degrees latitude
  • Formed cold sinking air moving from the poles
  • Creates cold air

Jet Streams

  • Separates warm air from cold air
  • The jet streams are narrow belts of high speed winds that blow in the upper troposphere and the lower stratosphere