Unit 9, Chapter 27

1. Unit 9, Chapter 27 Integrated Science

2. Unit Nine: Energy in the Earth System Chapter 27 Weather and Climate • 27.1 Earth's Heating and Cooling • 27.2 Global Winds and Currents • 27.3 Weather Patterns • 27.4 Storms • 27.5 Weather and Climate

3. Chapter 27 Learning Goals • Learn how Earth’s rotation, Earth’s axial tilt, and distance from the equator cause variations in the heating and cooling of Earth. • Learn how the heating of Earth’s surface and atmosphere by the sun causes convection cycles in the atmosphere and oceans, producing winds and ocean currents. • Learn about tools meteorologists use to predict weather, and how to read a weather map. • Make and test your own weather instrument. • Model a Doppler radar system. • Learn about the physical features that interact to form the climate of each of six important land biomes.

4. longitude prevailing westerlies polar easterlies temperate forest stratiform cloud stratocumulus cloud taiga temperature inversion trade winds tropical rainforest tundra warm front Chapter 27 Vocabulary Terms • air mass • El Niño-Southern Oscillation • biome • cold front • Coriolis effect • cumuliform cloud • desert • grassland • gyres • isobars • jet stream • latitude

5. Key Question: What causes seasons? 27.1 Variations in Earth's Heating and Cooling *Read text section 27.1 AFTER Investigation 27.1

6. 27.1 Heating and Cooling Earth • Satellite data is used to map patterns of heating and cooling. • The National Oceanic and Atmospheric Administration (or NOAA) uses infrared photography to map how much heat is reflected or emitted from different areas of Earth each day.

7. 27.1 Latitude • Latitude lines measure distance from the equator. • These lines run parallel to the equator and are labeled in degrees north or degrees south.

8. Longitude lines run vertically from the north pole to the south pole. The line that runs through Greenwich, England, is labeled 0 degrees longitude and is called the prime meridian. Lines east of the prime meridian are numbered from 1 to 179 degrees east, while lines west of the prime meridian are numbered from 1 to 179 degrees west. The 0- and 180-degree lines are not labeled east or west. 27.1 Longitude

9. 27.1 Temperature and Latitude • Earth’s temperature varies with latitude. • At higher latitudes, solar radiation is less intense. • The same thing happens to the sun’s energy when it reaches the south pole at an angle.

10. 27.1 Temperature and Rotation • As Earth rotates, the portion of the globe facing the sun warms as it absorbs more solar radiation than it emits. • Earth constantly emits some of the absorbed energy as infrared radiation. • This emission of heat cools the dark side of the planet.

12. 27.2 Global Winds and Ocean Currents • Thermalsare small convection currents in the atmosphere. • While thermals form on a local level, there are also giant convection currents in the atmosphere. • These form as a result of the temperature difference between the equator and the poles.

13. 27.2 Coriolis Effect • Bending of air currents is called the Coriolis effect, after the French engineer mathematician Gaspard Gustave de Coriolis (1792-1843), who first described the phenomenon in 1835.

14. 27.2 Global Winds • There are three important global surface wind patterns in each hemisphere: • trade winds • polar easterlies • prevailing westerlies

16. 27.2 Ocean Currents • Global wind patterns and Earth’s rotation cause surface ocean currents to move in large circular patterns called gyres.

17. Key Question: How do temperature and salinity cause ocean layering? 27.2 Global Winds and Ocean Currents *Read text section 27.2 BEFORE Investigation 27.2

18. 27.3 Weather Patterns • Three important factors that shape the weather in a given region are: • temperature • pressure • water • A sling psychrometer can measure water in the air.

19. 27.3 Phase changes of water • Water in the atmosphere exists in all three states of matter. • High in the troposphere, there are ice crystals. • Tiny water droplets, much too small to see, are suspended throughout the troposphere virtually all the time. • Other water molecules in the atmosphere are truly in the gas state, separate from all other molecules.

20. 27.3 Cloud formation • Different conditions cause different clouds. • Cumuliform clouds form when convection causes rising pockets of air in the atmosphere. • Cumuliform clouds include: • cirrocumulus • altocumulus • cumulus • cumulonimbus

21. 27.3 Cloud formation • Different conditions cause different clouds. • Stratiform clouds form when a large mass of stable air gradually rises, expands, and cools. • Stratiform clouds include: • cirrostratus • altostratus • nimbostratus

22. 27.3 Cloud formation • Sometimes a cloud formation combines aspects of both cumuliform and stratiform clouds. • We call these clouds stratocumulus clouds.

23. 27.3 Cloud formation • Cirrus clouds are thin lines of ice crystals high in the sky, above 6,000 meters. • They are just a thin streak of white across a blue sky.

24. 27.3 Precipitation • A raindrop begins to form when water molecules condense on a speck of dust. • At first it is round, but when it is large enough that it begins to fall, air resistance causes the underside of the drop to flatten, so that it looks more like a hamburger bun. • As it grows larger, it looks more like an upside down bowl with a thick rim. • If it hasn’t hit the ground by this point, it will break up into smaller droplets and the process repeats itself.

25. 27.3 Air masses and fronts • An air mass is a large body of air with consistent temperature and moisture characteristics throughout. • Changing atmospheric conditions and global wind currents eventually cause these air masses to move.

26. 27.3 Low and high pressure areas • When a cold front moves into a region and warm air is forced upward, an area of low pressure is created near Earth’s surface at the boundary between the two air masses. • A center of high pressure tends to be found where a stable cold air mass has settled in a region. • Isobars show areas with the same atmospheric pressure on map.

27. Key Question: How can we measure water content in the atmosphere? 27.3 Weather Patterns *Read text section 27.3 BEFORE Investigation 27.3

28. 27.4 Storms • Thunderstorms arise when air near the ground is strongly warmed and rises high into the troposphere. • As the air rises, it cools and condenses, forming a towering cumulonimbus cloud. • Eventually some of the cloud droplets become large enough to fall as rain. • a storm cell

29. 27.4 Hurricanes • Several conditions must be present for a rotating system to become a hurricane: • wind speeds of at least 74 miles an hour. • warm ocean water must be at least 46 meters deep. • the air must be warm and moist to a point at least 5,500 meters above sea level. • a tropical cyclone

30. 27.4 Tornadoes • A tornado, like a hurricane, is a system of rotating winds around a low pressure center. • An average tornado is tiny, compared with the average diameter of a hurricane. • However, the wind speeds of a tornado are much greater than those of a hurricane. • A tornado’s wind speed can reach 400 kilometers per hour. • a tornado

32. Key Question: How does Doppler radar work? 27.4 Storms *Read text section 27.4 BEFORE Investigation 27.4

33. 27.5 Weather and Climate • Climate is defined as the long-term average of a region’s weather. • Climate depends on many factors: • latitude • precipitation • elevation • topography • distance from large bodies of water

34. 27.5 Weather and Climate • Scientists divide the planet into climate regions called biomes. • An example of a biome is desert.

36. Key Question: How do zoos model climates? 27.5 Biomes *Read text section 27.5 BEFORE Investigation 27.5