Lecture 12 F 2010 - Lecture 12: Chapter 6, Atmospheric and...

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Lecture 12: Chapter 6, Atmospheric and Oceanic Circulations Today we will be discussing wind, which involves air pressure. A reminder: air pressure is pressure produced by the motion, size and number of gas molecules in the air and exerted on surfaces in contact with the air. It is measured by millibars (mb) here in the US. Air pressure differs over the surface of the earth. There are areas of high pressure and areas of low pressure. Areas of high pressure usually involve air that is _____________________. Pressure is high as the air becomes increasingly dense, and air molecules “pile” on top of one another, creating a ridge of air. Areas of low pressure usually involve air that is ________________________. Pressure is low and the air is less dense because the molecules are spreading out. The spread-out air molecules create a trough of air. Average sea level pressure is: T/F Areas of high pressure are dense, because air molecules pile on top of one another T/F Areas of high pressure form ridges T/F Areas of low pressure are very dense T/F Areas of low pressure create troughs. Wind What is wind? What produces wind? Winds are named for: For example, a wind from the west is a ___________________________; a wind from the south is a Matching 1. Involve air that is descending. 2. Involve air that is ascending and converging. 3. The horizontal movement of air across Earth’s surface 4. Differences in air pressure (density) between locations produce this. 5. Originates from the east and moves west 6. Originates from the west and moves east A. Wind B. Low Pressure C. High Pressure D. Westerly wind E. Easterly wind T/F Wind moves from low pressure to high pressure.
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Four forces determine the speed and direction of winds: 1. Gravitational force 2. Pressure gradient force 3. Coriolis force 4. Friction force 1. Gravitational Force Gravitational force: Gravity compresses the atmosphere worldwide, with density decreasing as altitude
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This note was uploaded on 02/01/2011 for the course GEOG 1112 taught by Professor Kumar during the Fall '08 term at Georgia State University, Atlanta.

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Lecture 12 F 2010 - Lecture 12: Chapter 6, Atmospheric and...

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