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* The relative measure of the amount of water vapor in the air * Psychrometer * Water vapor affects the density of the air. * Cold air is heavier than.

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Presentation on theme: "* The relative measure of the amount of water vapor in the air * Psychrometer * Water vapor affects the density of the air. * Cold air is heavier than."— Presentation transcript:

1 * The relative measure of the amount of water vapor in the air * Psychrometer * Water vapor affects the density of the air. * Cold air is heavier than warm air.

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3 * A body of air that has the same temperature and humidity throughout.

4 * If a large body of air sits over an area of land or water for a long period of time, it will take on the characteristics of the land or water beneath it. * Temperature * Humidity

5 * Air masses over the equator will have high temperatures. * Air masses over polar regions will have low temperatures. * Air masses over water (maritime) will have high humidity (moisture content). * Air masses over land (continental) will have low humidity (moisture content).

6 * Air masses tend to form in areas with little wind. * Remember, they sit over an area for a long period of time without moving.

7 maritime * Air masses that form over water are called maritime. continental * Air masses that form over land are called continental.

8 * mT * mT – maritime tropical * cT * cT – continental tropical * mP * mP – maritime polar * cP * cP – continental polar * cA * cA – continental arctic

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10 * mT * mT – warm, moist air * cT * cT – warm, dry air * mP * mP – cold, moist air * cP * cP – cold, dry air * cA * cA – super cold, dry air

11 Convection!

12 * Warm air rises, and cold air moves in to replace it. * A circulation pattern is formed. * Causes air and water currents to form

13 Density! * Warm air rises. * Cool air sinks.

14 How do different air masses form?

15 * Hurricanes

16 * What is a hurricane? * Hurricanes are tropical cyclones. * They form in the southern Atlantic Ocean, Caribbean, Gulf of Mexico, and eastern Pacific Ocean. * Their winds spiral outward in a counterclockwise, circulation pattern.

17 * What conditions must exist for a hurricane to form? * Low to medium winds blowing in the same direction * 5–30 degrees north of the equator in the ocean * Ocean surface temperature of greater than 80  F that extends down to about 150 feet deep (50 m) * Lower atmosphere must be moist

18 * How do hurricanes form? * The air mass above the tropical waters takes on the temperature and humidity of the water beneath it. * Incoming winds force the air upward. * The warm, moist air rises, forming water vapor and clouds. * Above the storm, the winds flow outward. * Outside winds blow inward, and the cycle repeats.

19 * How do hurricanes move? * Hurricanes turn to the right, away from the equator, because of the Coriolis Effect caused by Earth’s rotation. * You will learn about this phenomenon later in the lesson.

20 * Where does the energy for a hurricane originate? * The Sun heats the oceans. * Warm air rises, and as it cools, it releases energy, fueling the hurricane.

21 * Why don’t hurricanes form in higher latitudes? * The temperature of the oceans is not warm enough. * The distance is too far from the equator.

22 * Hurricane Katrina

23 * Reflective Question How do oceans play a role in the development of weather systems including hurricanes?

24 * Winds

25 * The movement of air in a horizontal direction * What is wind?

26 * The uneven heating of the Earth causes differences in air pressure. * What causes wind?

27 * The Sun’s energy is more concentrated at the Equator and spread out more over the poles. * Air over the equator is warm and less dense and has lower pressure. * Air over the poles is cold and denser and has higher pressure. * Why does this happen?

28 * As warm air at the equator rises, cooler air from the poles will move in and replace it. * Air pressure moves in a pattern from high to low. * Why does this happen?

29 * As warm air at the equator rises, cooler air from the poles will move in and replace it. * Convection

30 * The density changes caused by temperature changes create convection cells. * These cause circular patterns of air that circulate over the whole planet. * Global Convection Currents

31 * Where the convections cells meet, prevailing winds and jet streams form. * They blow from one direction over a certain area of the Earth’s surface. * Global Wind Belts

32 * Jet Stream

33 * Forms high in the upper Troposphere between two air masses of different temperatures * Higher temperature difference = faster speed * Due to the Coriolis Effect, it flows around air masses. * Polar Jet: * It dips southward when frigid polar air masses move south. * It tends to stay north in the summer months.

34 * Jet Stream Animation html

35 * Named for the direction from which they blow: * Polar Easterlies * Polar Easterlies – High latitudes blow east to west toward the equator * Westerlies * Westerlies – Mid latitudes blow west to east toward the poles * Easterlies (Trade Winds) * Easterlies (Trade Winds) – Low latitudes blow east to west toward the Equator * Prevailing Winds

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37 * Pressure belts form in between the wind belts. * Prevailing Winds

38 0 o Equator 30 o S 60 o S 90 o S 30 o N 60 o N90 o N MoreDirect Sun Hot

39 * The winds from the poles blow toward the equator. * The winds from the equator blow toward the poles. * Global Wind Belts

40 …then why is it defined as the horizontal movement of air? Does the Earth stand still? * If wind is moving north and south, …

41 * As the Earth rotates counterclockwise, the winds bend and curve around the Earth. * Gustave-Gaspard Coriolis, an engineer and mathematician, described this effect as an inertial force in * The Coriolis Effect

42 * In the Northern Hemisphere, winds bend to the right of their direction of travel. * In the Southern Hemisphere, winds bend to the left of their direction of travel. * Let’s try a little investigation to see how this works. * The Coriolis Effect

43 * Weather patterns and systems move in a circular motion due to the bending of the winds caused by the Earth’s rotation. * The Coriolis Effect

44 * Our Earth is always seeking balance. * In an effort to find balance, there is a continuous cycle of patterns. * What is the driving force behind the changes that create these patterns? * Equilibrium

45 How are winds produced? * Reflection Question

46 Ocean Current s

47  Warm currents flow away from the equator.  Cold currents flow toward the equator. * Ocean Currents

48 * Sun * Wind * Coriolis * Gravity * Factors Influencing Currents

49 * Energy from the Sun heats the water. * Warm water is less dense that cold water. * Warm water rises, and cold water sinks. * As warm water rises, cold water moves it to replace it. * Sun

50 * Convection Cycle

51 * Just as wind moves from high pressure to low pressure areas, so does the water. * Winds blow across the surface of the water, causing friction. * The water piles up because the surface currents flow slower than the winds. * Wind

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53 * As water piles up and flows from high pressure to low pressure, gravity will pull down on the water. * This forms vertical columns or mounds of water. * The Coriolis Effect causes the water to curve. * Gravity

54 * Causes water to move to the right in the Northern Hemisphere * Causes water to move to the left in the Southern Hemisphere * The Coriolis Effect

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56 * Make up 10% of oceans’ water * Up to maximum depth of 400 m * Surface ocean currents are caused by the surface wind patterns. * Surface Currents

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58  Vertical columns or mounds of water at the surface and flow around them  Produce enormous circular currents  Five major locations:  North Pacific - clockwise  South Pacific - counterclockwise  Indian Ocean - counterclockwise  South Atlantic - counterclockwise  North Atlantic - clockwise * Gyres

59 * Oceanic Gyres

60 * A strong surface current * Begins at the tip of Florida * Flows up the eastern coastline of the U.S. * Crosses the Atlantic Ocean * Causes warmer climate in NW Europe * Gulf Stream

61 * Surface waters blow to the right of the wind. * As less dense, surface water moves off shore, cold, deep, denser waters come to the surface to replace them. * Upwelling

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63 * The Great Ocean Conveyor: Helps maintain Earth’s Balance

64 * Make up about 90% of oceans’ water * Differences in density cause them to move. * Differences in density are related to temperature and salinity. * At high latitudes, they sink deep into the ocean basins. * Temperatures are so cold, they cause the density to increase. * Deep Water Currents

65 * How are ocean currents produced? * Reflective Question

66  Abnormally high surface ocean temperatures off the coast of South America  Causes unusual weather patterns across the globe * El Nino

67 * Starts because the easterly trade winds weaken and allow the warm waters in the Western Pacific to move east toward South America * This changes where the convection current occurs. * Causing rain where it usually doesn't occur and drought where it usually rain s * El Nino

68 * El Nino Winter

69 * El Nino Summer

70  Abnormally low surface ocean temperatures off the coast of South America  Causes unusual weather patterns across the globe * La Nina

71 * Ocean currents move more slowly than winds. * Oceans hold more heat than the atmosphere and land. * Cold currents will cause nearby coastlines to be cooler. * Warm currents will cause nearby coastlines to be warmer. Where do the cold currents come from? The warm currents? * Ocean’s Effect on Climate

72 * Predictable Patterns How do these currents affect the climate of the coastline?

73 * How do our oceans impact climate? * Reflection Questions

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