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Air Pressure and Winds

Air Pressure and Winds. Triple A Productions A rnold Roberts A llison Couch A my Jacobs. Air Pressure. Air Pressure : The weight of the atmosphere as measured at a point on the earth’s surface . How do differences in air pressure from place to place affect weather conditions?.

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Air Pressure and Winds

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  1. Air Pressure and Winds Triple A Productions Arnold Roberts Allison Couch Amy Jacobs

  2. Air Pressure Air Pressure: The weight of the atmosphere as measured at a point on the earth’s surface. How do differences in air pressure from place to place affect weather conditions?

  3. Air is a gaseous substance whose weight affects air pressure.The air is heavier and the air pressure is higher closer to the earth’s surface

  4. Physical law For equal amounts of cold and hot air, the cold air is denser.A cold morning is characterized by relatively heavy air, but as afternoontemperatures rise, air becomes lighter.

  5. Barometers A variety of barometers are to record changes in air pressure.The air pressure at a given locationchanges as the surface heats or cools.Barometers record the drop in atmospheric pressure when the air heats and the rise in pressure as the aircools.

  6. Air Density Visualize air as two liquids with different densities,like oil and water:The lighter liquid will move to the topas the denser liquid will move to the bottom of the container becoming the same thickness everywhere; in order to attain equilibrium by evening out pressure imbalances resulting from the heating and cooling processes.The heavier (cold) air moves to locations with light (warm) air .

  7. Pressure Gradient Force Pressure differences existing between areas cause air to blow from an area of high pressure toward an area of low pressure

  8. Balancing Pressure Differences Warm Air Wind High Pressure Zone Heavy Air Low Pressure Zone Heavy air stays close to the Earth’s surface Winds are produced Warm air is moved in an upward motion

  9. Differences in Pressure Zones If distance between high and low are short 1. pressure gradient is steep 2. wind velocities are great If gentle air movements occur when zones are far apart 1. the degree of difference is not great

  10. Convection System The circulatory motion of descending cool air and ascending warm air

  11. Land and Sea Breezes Good example of a convectional system.Daytime: The warmer air over theland rises vertically, and is replaced by cooler air from over the sea.Breeze from sea.Nighttime: The water is warmer thanthe land, moving the cooler air from over the land to the sea.Breeze from land.

  12. Mountain and Valley Breezes Gravitational forces cause the heavy cool air that accumulates over snow in mountainous areas to descend into the lower valley areas. Valley Breeze: the warm air from the valley movesup the slopes into the mountainous regions. This usually occurs during the day.Mountain Breezes: the cool air moves down the slopes into the valley , lowering the temperatures in the valley (with the potential of freezing). This usually occurs at night.

  13. The Coriolis Effect As winds move from high pressure to low pressure: winds in the N. Hemisphere tend to travel to the right, winds in the S. Hemisphere tend to travel to the left

  14. Coriolis Effect The skaters in the middle of the circle do not need to move very quickly, while the out most skaters have to move rapidly to maintain this line

  15. How does this relate? The Earth rotates on its axis Equatorial regions are rotating much faster Polar regions are rotating much slower

  16. Coriolis Effect with Pressure Gradient Force When together they produce spirals rather then straight lines of wind The spiral is the basic form of many storms

  17. The Frictional Effect The cause of wind to follow an intermediate path

  18. Wind Movements are slowed due to friction on Earth’s surface Friction becomes ineffective about 1 mile above the Earth’s surface Friction causes wind speed to decrease and change direction

  19. Global Air Circulation • Equatorial Low Pressure • Areas of low pressure at the equator line • Subtropical High Pressure • Cooled heavier air from the equatorial air pressure • Northeast Trades and Westerlies (Southwesterlies) • Belts of wind caused by the cooled air reaching the earths surface • Polar Air Pressure • Subpolar low is ascending air north of the westerlies • Polar Easterlies connect the Subpolar low to the Polar high pressure • Has the greatest effect on Jet Streams cosscience1.pbworks.com

  20. Jet Streams • Strongest flows of upper air wind • 30,000 – 40,0000 feet from the earths surface • Air travels East to West, in both hemispheres, at 100 – 200 MPH • Tends to separate cold polar air from warm tropical air • Movement of the Jet Stream has the greatest effect on monsoon season in Southeast Asia

  21. Monsoons • Monsoon wind changes directions seasonally • Sothern and Eastern Asia is effected by this phenomena the most

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