GPHY 102 Lecture Notes - Lecture 6: Atmospheric Circulation, Wind Direction, Barometer

• School: Queen's University
• Department: Geography
• Course: GPHY 102
• Professor: Dr.Trezino

Document Summary

Environment, 5th edition, john wiley & sons, chapter 5 (pp. Objectives: describe measurement and variation of atmospheric pressure, explain processes impacting wind direction and weather systems, describe patterns of atmospheric pressure and circulation, evaluate the role of upper atmospheric circulation. To top of atmosphere: force (per unit area) exerted by weight of a column of air, typically measured with a barometer - mb or kpa, varies slightly (~5%); but small differences can be significant. Altitude: air pressure deceases rapidly with increasing altitude, decrease is not linear, because atmosphere thins. Winds and pressure gradients: wind is air in (predominantly) horizontal motion, characterized by a direction and speed, flows from high to low pressure, pressure gradient. Greater pressure differences create faster wind speeds. Differences in air pressure = a pressure gradient. The pressure gradient force acts at right angles to the isobars (90 degrees).