1. References: -Air Command Weather Manual Ch 5, 11, -FTGU pages 129-132
Ground School: Meteorology
5.07 Wind
References: -Air Command Weather Manual Ch 5, 11, -FTGU pages
40 Minutes

2. 5.07 Meteorology – Wind
Review from 5.06
Poll – 3 questions

3. Terminology and background Low level and Surface Winds Diurnal Effects
5.07 Meteorology – Wind
MTPs:
Terminology and background
Low level and Surface Winds
Diurnal Effects
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4. Wind the horizontal movement of air
5.07 Meteorology – Wind
Wind
the horizontal movement of air
created by pressure differences in the horizontal

5. 5.07 Meteorology – Pressure Gradient
the rate of change of pressure over a given distance
measured at right angles to the isobars
close together = steeper gradient and stronger winds
further apart = shallower gradient and weaker winds

6. 5.07 Meteorology – Pressure Gradient

7. 5.07 Meteorology – Wind
Veering
Wind changes direction clockwise
Wind veers and increases during the day
Wind veers and increases with increase in altitude
Backing
Wind changes direction counter-clockwise
Wind backs and decreases at night
Wind backs and decreases with descent in altitude

8. 5.07 Meteorology – Pressure Gradient
Example:
Winds start the day at 300o and by 1400 the winds are 340o and by night they are 310o

9. 5.07 Meteorology – Coriolis Force
Earth turns below atmosphere
In N Hemisphere deflected to the right
To left in S Hemisphere

10. 5.07 Meteorology – Confirmation
Questions:
Wind is:
The horizontal movement of air created by pressure differences (horizontal)
Pressure Gradient is:
The rate of change of pressure measured over a given distance, measured at right angles to the isobars
Backing is:
Change in direction anti-clockwise
Describe Coriolis Force
Rotation of earth causes air to be deflected to the right in the N Hem. Until parallel with the isobars

11. 5.07 Meteorology – Surface Friction
Friction between surface and atmosphere slows movement of air, this in turn slows Coriolis force
Only up to a few thousand feet (except in mountainous regions)

12. Gusts a brief rapid increase of wind speed.
5.07 Meteorology – Gusts
Gusts
a brief rapid increase of wind speed.
may be associated with a rapid change in wind direction
Causes may be related to mechanical turbulence and unequal heating

13. 5.07 Meteorology – Confirmation
What is surface friction and what are it’s effects?
Friction between surface and atmosphere
Slows movement of air and therefore Coriolis force
Air tends to move across isobars at slight angles
Gusty conditions may be caused by
Mechanical turbulence
Uneven heating of the earth

14. 5.07 Meteorology – Diurnal Effects
If isobaric pattern and pressure gradient are identical
During day…
At night…

15. 5.07 Meteorology – Diurnal Effects
Land and Sea Breezes

16. 5.07 Meteorology – Diurnal Effects

17. 5.07 Meteorology – Diurnal Effects

18. 5.07 Meteorology – Diurnal Effects
Memory Tool
Ana goes up and throws the Kat down.

19. 5.07 Meteorology – Diurnal Effects

20. BC Online Ground School 5.07 Meteorology – Diurnal Effects

21. When do sea breezes occur? What causes a Katabatic wind?
5.07 Meteorology – Review
When do sea breezes occur?
During the day – high pressure over water, low over land.
What causes a Katabatic wind?
At night, air in contact with slope cools, becomes more dense, and flows down hill.
What is it called when vapour changes to liquid?
Condensation

22. 5.07 Meteorology – Review
Effects of a Hurricane