Chapter 2, Section 3

What is wind? The horizontal movement of air from an area of HIGH pressure to an area of LOW pressure

What causes wind? All winds are caused by the differences in air pressure

How do fluids move? From areas of HIGH pressure to areas of LOW pressure.

Differences in air pressure are caused by unequal heating of the atmosphere. (Difference temperatures of the air) What causes differences in air pressure?

How is wind direction measured? Wind is measured with a wind vane. The wind vane points in the direction the wind comes from. Winds are also named from the direction they come from.

How is wind speed measured? Wind speed is measured with an anemometer.

What is the wind-chill factor, and how does it affect us? The increased cooling that winds can cause. It is what the air “feels like,” not the actual temperature. (Cool air moves across your much warmer skin)

What are local winds? Local winds are winds that blow over short distances. They are caused by unequal heating of Earth’s surfaces within a small area. This causes differences in air temperature.

What is a sea-breeze and why does it occur? A sea-breeze is a light wind that comes from the sea or ocean. It usually occurs during the day because the sand heats up more than the water creating a convection current.

What is a land-breeze and why does it occur? A land breeze is a light wind that comes from the land. It usually occurs during the night because the sand cools down more than the water creating a convection current.

What is a monsoon? A monsoon is a land or a sea breeze over a large region that changes directions with the seasons.

Explain summertime monsoons. During the summer, the land is warmer, air over the land rises, cooler air from over the water (carrying water vapor) moves in to replace the rising air. The water vapor creates long periods of heavy rain.

Explain wintertime monsoons. During the winter, the water is warmer, air over the water rises, cooler air from over the land moves in to replace the rising air. This creates very dry conditions.

What are global winds? Global winds are winds that are steadily blown over huge distances.

What causes global winds? Global winds are caused by global convection currents and the Coriolis Effect. Warm air rising near the equator and cold air sinking near the poles. The cold air replaces the warm air producing huge global convection currents

Where do global convection currents RISE? Global convection currents rise near the equator because the air is warmest.

Where do global convection currents SINK? Global convection currents sink near the poles because the air is coolest.

What is the Coriollis effect? The Coriollis effect is the way that the Earth’s rotation causes the winds to curve.

What are the DOLDRUMS and where are they found? An area of calm air near the equator where warm air is rising causing very little wind.

What are the HORSE LATITUDES and where are they found? An area of calm air near 30° North and 30° South where cool air is sinking causing very little wind.

What are the TRADE WINDS and where are they found? Winds that blow from about 30° North and 30° South towards the equator and turn towards the west Also known as the Prevailing Easterlies

What are the PREVAILING WESTERLIES and where are they found? Winds that blow from about 30° North and 30° South towards 60° North and 60° South and turn towards the east *These are the winds that affect our weather most.*

What are the POLAR EASTERLIES and where are they found? Winds that blow from about 60° North and 60° South towards the poles and turn towards the west

What are the POLAR FRONT and where are they found? An area of calm air near 60° North and 60° South where warm air is rising causing very little wind.

What are Jet Streams? Jet streams are bands of high speed winds that are about 10 km above the Earth’s surface.