Download Wind Notes - Northside Middle School

Wind Notes
Wind is the movement of air from a region of high pressure to a region of lower pressure.
These areas of high and low pressure are created from temperature differences caused by
the sun heating the earth, which in turn heats the atmosphere.
• Air moves from high to low pressure area so the lower the pressure area the
stronger the wind
Local winds are.
• Winds that blow over short distances
• Caused by unequal heating of the earth’s surface within a small area
• Form only when no winds are blowing from far away
Sea (large open water) Breeze onto
Land: Land heats more quickly during
day than the adjacent water. A seabreeze is formed by increasing
temperature differences between the
land and water which create a pressure
low over the land due to its relative
warmth and forces higher pressure,
cooler air from the sea to blow onto the
land.
Land Breeze from sea or a Lake- At
night, the land cools off quicker than the
open water. If the land cools below that
of the adjacent open water, the pressure
over the water will be lower than that of
the land. This creates a land breeze
flowing back out towards the open
water.
Valley Breeze: (occurs mainly in
afternoons): During the day, sunlight
warms valley walls, which warm the air
in contact with them. The heated air
rises and forms the valley breeze. As
the warm air rises and cools over the
mountains, clouds may form from the
warm moist air condensing..
Mountain Breeze: (occurs evenings and
night): This wind is formed at night by the
cooling along mountainsides. As the
slopes become colder than the surrounding
atmosphere, the air closest to the
mountainside cools and drains down into
the valley. The cool air sinks and forms
mountain breeze.
Global Winds- Global winds blow steadily from a specific direction over long distances
• The movement air makes between the equator and the poles produces global
winds.
The Jet Stream- Jet streams are relatively narrow bands of strong wind in the upper levels
of the atmosphere. The winds blows from west to east in jet streams but the flow often
shifts to the north and south. Jet streams follow the boundaries between hot and cold air.
Since these hot and cold air boundaries are most pronounced in winter, jet streams are the
strongest for both the northern and southern hemisphere winters
Wind is measured with a tool called the Anemometer.