Crop Weather Relationships

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Module 3 Weather Elements
Virtual Academy for the Semi Arid Tropics
Modules
Lessons

Lesson 6 Wind velocity
After completing this Lesson, you will be able
to answer 1. What is wind and how wind
moves? 2. What is anemometer ? 3. How cup
anemometer measures wind speed?
Course on Crop-Weather Relationships
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Lesson 6 Wind velocity

• Winds begin with differences in air-pressures.
• Pressure that is higher at one place than another
  sets up a force pushing from the high toward the
  low pressure.
• The greater the difference in pressures, the
  stronger will be the wind force.

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Lesson 6 Wind velocity

• The distance between the area of high pressure
  and the area of low pressure also determines how
  fast the moving air is accelerated i.e. Wind
  velocity.
• Wind velocity includes both wind speed and wind
  direction.
• Wind velocity is measured using anemometer in a
  weather station.

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Lesson 6 Wind velocity

• Anemometer
• Cup anemometer is used to measure the wind speed
  from the speed of rotation of a windmill which
  consist of 3 or 4 hemispherical or conical cups,
  each fixed to the ends of horizontal arms
  attached to a vertical axis.
• Rotation of cups is transmitted to a technical
  counter which records the wind speed.

Cup anemometer
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Module 3 Weather Elements
Virtual Academy for the Semi Arid Tropics
Modules
Lessons

This concludes Lesson 6 on wind velocity in this
Module. The last Lesson in this Module is about
cloud cover. Click Lessons button to select
Lesson 7
Course on Crop-Weather Relationships