Coriolis effect

Wind Structure

1. Coriolis Effect MAHMUD SAIFULLAH ( 王方 ) L163330114

2. 2. Evidence for Rotation Coriolis Effect – the tendency of objects moving over the earth (air, water, planes, projectiles) to be deflected (curve away) from a straight line path. The French scientist, Gaspard Coriolis, first explained the deflection of objects moving over the surface due to Earth’s rotation The deflection is to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This deflection occurs because Earth’s surface is rotating with respect to the objects.

3. Actual motion

4. North Pole Projectile A hockey puck is launched from the north pole. As it heads south, the earth turns to the east, causing the puck to appear to deflect to the west as viewed by an earthbound observer. Legend: Red: Path on rotating earth Gray: Path on stationary earth

5. Coriolis Effect The tendency for any moving body on or above the earth's surface, e.g., an ocean current, wind or an artillery round, to drift sideways from its course because of the earth's rotation.

6. The true shape of the Earth called an Oblate Spheroid. The diameter from the North Pole to the South Pole (the shortest diameter) is approximately 12,714 km. The equatorial diameter (the longest diameter) is approximately 12,756 km. This is not a big difference, but it does make the Earth not quite a sphere.

7. Something hanging from a fixed point which, when pulled back and released, is free to swing down by force of gravity and then out and up because of its inertia. Inertia: means that bodies in motion, will stay in motion; bodies at rest, will stay at rest, unless acted on by an outside force.

8. Evidence of Earth’s Revolution around the Sun Seasonal Constellations: Because of the Sun’s annual motion, some constellations are visible at night only during certain seasons. Constellations are visible when the dark side of Earth (away from sun) faces toward the constellation.

9. Severe Weather

10. Hurricanes, Thunderstorms, and Tornadoes

11. Ingredients for a storm… Heat From the Sun Differences in Air Pressure Water

12. What is a hurricane? A hurricane is a large, swirling, low-pressure system that forms over the warm Atlantic Ocean.

13. Hurricanes form over warm ocean water. Near the equator , warm ocean water provides the energy that can turn a low pressure center into a violent storm. As water evaporates from the ocean, energy moves from the ocean water to the air. This energy makes warm air rise faster. Tall clouds and strong winds develop.

14. As winds blow across the water from different directions into the low, the Coriolis Effect bends their path into a spiral. The winds blow faster and faster, around the low, which becomes the center of a storm system.

15. Parts of a Hurricane

16. Parts of a Hurricane Eye - The calm, center of the hurricane. Eyewall - The wall of dense thunderclouds surrounding the eye. The strongest winds of the hurricane are in the eyewall. Spiral Rainbands - A series of long, spiraling bands of rain clouds in a hurricane.

17. Why do hurricanes seem to die over land? As long as a hurricane is over water, the warm, moist air rises and provides energy for the storm. When a hurricane reaches land, however, its supply of energy disappears and the storm loses power.

18. Tornadoes Tornadoes form from severe thunderstorms . They are very destructive because they have a high energy density . They also don't last very long. This makes it hard to learn about them. Since scientists don't know much about tornadoes, it's also hard to forecast them

19. Tornadoes The fastest recorded wind speed is 230 miles per hour and occurred in New Hampshire in 1934. Although, winds can get faster in tornadoes . The windiest place in the world is in Antarctica .

20. In severe thunderstorms, wind at different heights blows in different directions and at different speeds. This difference in wind speed and direction, called wind shear, creates a rotating column parallel to the ground.

21. A thunderstorm’s updraft can tilt the rotating column upward into the thunderstorm creating a funnel cloud. If the funnel comes into contact with Earth’s surface, it is called a tornado.

22. Tornado Alley This map shows where most tornadoes form in the United States. The red area is known as " Tornado Alley ". Warm moist air from the Gulf of Mexico collides with Cold dry air.

23. Thunderstorms It is late afternoon. The white puffy clouds that have been growing all day are replaced by a greenish sky. A distant rumble is heard...then another. It starts to rain . A flash of light streaks the sky, followed by a huge BOOM. Welcome to a thunderstorm.

24. Thunderstorms Thunderstorms are small, intense weather systems that produce strong winds, heavy rain, lightning, and thunder.

25. When do thunderstorms occur? Thunderstorms form from warm moist air and along cold fronts.

26. How are thunderstorms created? There are three ingredients for thunderstorms to form: 1. The air near the earth’s surface must be warm and moist . It rises or moves upward, which is called an updraft. 2. The atmosphere must be unstable - the surrounding air is colder than the rising air mass. As the warm air mass rises, it cools and turns into water vapor, condenses and forms CUMULONIMBUS Clouds .

27. Vertical Air Movement As the cloud continues to build, ice particles form near the top of the cloud. As they get large-they form H-A-I-L . As the ice particles or H-A-I-L falls, cold air moves down with it, causing a downdraft .

28. Let’s Investigate! How do updrafts form??? Draw and describe what happens. In what ways is this demonstration of water similar to warm air in a thunderstorm? Challenge: How could you create a downdraft in this experiment?

29. Building Characteristics Preventing Hurricane, Tornado The foundation Wind acting on the roof surfaces of a building can cause negative pressures that create a lifting force sufficient to lift the roof off the building.  Once this occurs, the building is weakened considerably and the rest of the building will likely fail as well. To minimize this vulnerability, the upper structure ought to be anchored through the walls to the foundation. Several methods can be used to anchor the roof. Typically, roof trusses are "toenailed" into the top of the walls, which provide insufficient force to resist high winds.  Hurricane ties   nail into the wall and wrap over the trusses to provide higher force resistance.

30. Building Characteristics Preventing Hurricane, Tornado Earth-sheltering Earth-sheltered  construction is generally more resistant to strong winds and tornadoes than standard construction. Cellars and other earth sheltered components of other buildings, can provide safe refuge during tornadoes.

31. Building Characteristics Preventing Hurricane, Tornado Dome homes The physical geometry of a building affects its aerodynamic properties and how well it can withstand a storm. Geodesic dome roofs or buildings have low drag coefficients and can withstand higher wind forces than a square building of the same area. Even stronger buildings result from  monolithic dome   construction.

32. Migrant Head Start Center, Genola , Utah .

33. Building Characteristics Preventing Hurricane, Tornado Log house A CAT 5 hurricane-proof  log house   is resistant to the winds up to 245 mph. Wall logs in such construction have to be made of  glued laminated timber   and all other components of the house have to be hurricane-resistant.

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