Flashcards in Chapter 6 Deck (67)
Driving force behind wind
Winds are driven by: the imbalance between equatorial energy surpluses and polar energy deficits
Atmsopheric Circulation is Categorized at ___ levels.
1. primary circulation
2. secondary circulation
3. tertiary circulation
consists of general worldwide circulation (saharan dust for example)
consists of high pressure and low pressure systems
consists of local winds and temporal weather patterns
Winds moving principally North or South along meridians of longitude
Winds moving East or West along parallels of latitude
weight of the atmosphere described as force per unit area
- air molecules create air pressure through their motion, size and number. this pressure is exerted on all surfaces in contact with air.
- The horizontal motion of air across Earth's surface
- produced by differences in air pressure (Density) between one location and another produce wind
Winds are named for the direction from ________
which they originate!!!
Driving Forces behind wind speed and direction of wind within the Atmosphere
1. Earth's Gravity
2. Pressure Gradient Force
3. Coriolis Force
4. Friction Force
Pressure and Density _____ with altitude
Why does the experience of "thin air" occur?
caused by the smaller amount of oxygen to inhale. (fewer air molecules mean less oxygen)
Symptoms of acute mountain sickness (thin air)
- shortness of breath
Why is hot air less dense than cold air?
- Heating air increases molecular activity and temperature.
- Increase in molecular activity results in greater spacing between molecules, decreasing density and air pressure
-cold air is heavy and dense, so sinks and increases pressure
How does water vapour in air affect density?
- Moist air is lighter
- Because the molecular weight of water is less than that of the molecules making up dry air
- As water vapour in the air increases, density decreases, so humid air exerts less pressure than dry air.
warm, humid air is associated with _____ p____ and cold, dry air is associated with ______ p____
warm, humid air is associated with low pressure
and cold, dry air is associated with high pressure
Another word for wind
Any instrument that measures air pressure
- A device that measures air pressure using a column of mercury in a tube
- One end of the tube is sealed, the other end is inserted in an open vessel of mercury
-if the pressure is high the air pressure will push the liquid mercury and the higher the mercury will rise inside that glass tube
a measure of force per square metre of a surface area.
Standard of normal sea-level pressure
at 1013.2 mb or 29.92 in. of mercury (Hg).
In Canada and other countries, normal air pressure is expressed as
Standard of normal air pressure in Canada and some other countries is expressed as
101.32 kPa (kilopascal; 1 kPa = 10 mb)
An instrument that measures wind velocity.
Instrument that measures wind direction
Wind’s two principal properties
Speed and Direction
How does Gravity affect wind?
- The pressure that Earth’s gravitational force exerts on the atmosphere is virtually uniform
- Gravity equally compresses the Earth's atmosphere, with density decreasing as altitude increases
- The gravitational force counteracts the outward centrifugal force acting on Earth
- Without gravity, there would be no atmospheric pressure—or atmosphere, for that matter
How does Pressure Gradient Force affect wind?
- drives air from areas of higher barometric pressure to areas of lower barometric pressure, causing winds
Why do High and Low pressure areas occur on Earth?
- Principally because the Earth is unequally heated
- Cold, dry, dense air at the poles exerts greater pressure than warm, humid, less-dense air along the equator
- when masses of air are near each other, a pressure gradient develops and leads to horizontal air movement