GPHY 102 Lecture Notes - Lecture 7: Atmospheric Circulation, Axial Tilt, Cool Air

• School: Queen's University
• Department: Geography
• Course: GPHY 102
• Professor: Ryan K Danby

Document Summary

Objectives: describe measurement and variation of atmospheric pressure, explain processes impacting wind direction and weather systems, describe patterns of atmospheric pressure and circulation, evaluate role of upper atmospheric circulation, describe circulation patterns of the oceans. Atmospheric pressure: 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 difference can be significant. Atmospheric pressure and altitude: air pressure decreases 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 difference create faster wind speeds. Simple convection loop: heating of air at x causes air to expand and push isobaric surface upward, because pressure is increased, air begins to flow from point x to a and b.