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Factors Affecting Wind


    1.    Describe the Coriolis effect.

    2.    Explain how the Coriolis effect, friction, and pressure gradients affect wind direction.

Key Terms:

    Coriolis effect        jet stream

Notes: (19-2)

Wind is the product of pressure gradients established between high and low pressure systems.  These systems are constantly moving and changing.  This constant movement of the pressure systems is due to the Coriolis effect.  The Coriolis effect describes the apparent deflection (curving) of an object traveling in a straight line.

Caused by the rotation of Earth on its axis
Causes objects to curve westward (to their right Northern Hemisphere)
Greatest at the poles
Greater with fast moving objects - planes, rockets
Greater with objects traveling long distances - wind, ocean currents
Does not depend on the object's direction

(zebu.uoregon.edu/~js/glossary/ coriolis_effect.gif)

The Coriolis effect turns our high pressure systems clockwise (anticyclonic) and low pressure systems counterclockwise (cyclonic).

Basic Surface Map Showing High and Low Pressure Systems and Isobars

Surface Data Plot Showing a Low Pressure System

(www.crh.noaa.gov/lmk/soo/ docu/wx_cyclone3.gif)

Friction and the Coriolis Effect

Since the Coriolis effect is greater with faster moving objects, friction has a direct effect on the deflection of the wind currents.

The greater the friction the less the Coriolis effect deflects wind
With surface winds the Coriolis effect is affected by different surfaces as follows - water > smooth land > rough land
The Coriolis effect is greatest at high altitudes where the wind is the greatest
The jet stream is an extremely swift moving current that stretches from east to west across the United States

Monday US Jet Stream Forecast

(image.weather.com/images/maps/ aviation/jet1_720x486.jpg)









Last modified: March 25, 2003