1. Ancient Wind Measurement
Wind vanes were perhaps the most ancient meteorological instruments.
Mesopotamian and Sumerian documents, dating back nearly 4,000 years, describe primitive wind vanes, and streamers were used for wind direction measurement in China during the second century B.C.E.

2. 101 Wind

3. Why Wind? Created by differences in pressure.
Air accelerates from high to low pressure
Wind is simply the movement of air

4. Ancients had other ideas…

5. Wind Measurement
The famous Tower of the Winds in Athens, dating back at least to 50 B.C.E., was topped by a wind vane in the form of a Triton
Wind vanes and wind banners were common during the Middle Ages, and were found on many churches, ships, and towers.

7. Wind direction can be measured with wind vanes

8. More modern version

9. Wind speed is measured using anemometers

10. Development of anemometers

11. Modern Three-Cup Anemometer

12. Combo

14. Sometimes anemometers and wind vanes have had icing issues.

15. New Sonic Anemometer
Old
The solution….

16. Sonic Anemometer

17. Wind Terminology
Wind direction is the direction from which the wind is coming
Easterly wind from the east
Westerly wind from the west
Given in cardinal directions ..or..

18. Wind Direction (degrees) Professionally—generally degrees used

19. Speed Generally given in knots
1 knot = 1 nautical mile per hour= 1.15 mph
1 knot is ~ .5 meter per second

21. Proper Exposure of Wind Instruments
Open area
Sensors at 10 m (roughly 30 ft) above the ground
Not above pitched roof.

22. Sustained Winds and Wind Gusts
Sustained: usually average of 1-2 minutes
Gusts: typically strongest 3-5 second average wind reported during a period.
Typically about a ratio for (gust/sustained), but can be much more in some occasions.

25. You Can Often See Gusts Over Water—called “cat’s paws”

27. Why Gusts?

28. Winds are often far stronger over water than land
Water is much smoother aerodynamically than land
Trees, building, hills, etc. all slow down winds near the surface.
Wind over water can be % stronger (or more) than over land.

32. Estimating Wind Subjectively
Wind direction: flags, low clouds, trees and branches, throw grass in air
Wind speed: Beaufort Scale

33. Sir Francis
Beaufort, 1805

34. Wind Terminology Gale: 34-47 knots Storm: 48-64 knots
Hurricane: 65+ knots

35. Strongest Near Surface Winds
Anemometer: 231 mph, Mt. Washington, NH 1934
Radar: 318 mph, OK City Tornado, 3 May 1999

36. The NW Wind Record

37. Columbus Day 1962: At Cape Blanco there were 150 mph with gusts to 179
Columbus Day 1962: At Cape Blanco there were 150 mph with gusts to 179! Strongest winds on bluffs and windward slopes of coastal orography