Meteorology

1. Meteorology 7th Science

2. Gasses of the Atmosphere • Read U3L1F pages 104-111 • Atmosphere: the mixture of gases that surrounds the Earth (a.k.a air) • 78% nitrogen gas • 21% oxygen gas • 1% other gases • Also contains dust, ash, salt, smoke, bacteria, skin, and pollen Homework: • Create a pie chart in Microsoft Excel or Word that shows the gasses that make up the atmosphere. • Then recreate the table on page 109 with the answers filled in

3. Layers of the Atmosphere • Thermosphere (uppermost layer) • Air pressure decreases • Temperature increases • Mesosphere • Air pressure decreases • Temperature decreases • Stratosphere • Air pressure decreases • Temperature increases • Troposphere (lowest layer closest to Earth) • Air pressure decreases • Temperature decreases

4. Greenhouse Effect • Greenhouse effect: the process by which gases in the atmosphere such as water vapor and carbon dioxide, absorb and give off infrared radiation • Keeps the Earth warm • Some of the energy is absorbed by Earth the rest is released into space • Earth’s average temperature is 15 C (59 F)

5. How land and water retain heat and absorb water at different rates. • Read U3L2E pages 114-125 • Land warms up at a faster rate than the water and air do • Specific heat: the different rates at which materials become warmer or cooler • Substances with high specific heat take a lot of energy to show an increase in temp • Substances with a lower specific heat require less energy to show the same increase in temp • Which has a higher specific heat; water or land?

6. Humidity, Relative humidity and dew point • Read Unit 4 Lesson 1 pages154-161 • Humidity: amount of moisture in the air • As more water evaporates and becomes water vapor, the more humidity there is in the air

7. Humidity, Relative humidity and dew point • Relative humidity: the amount of water vapor in the air compared to the amount of water vapor needed to reach saturation • Saturated air: the rates of evaporation and condensation are equal

8. Humidity, Relative humidity and dew point • Dew point: the temperature at which more condensation than evaporation occurs • Air temp drops below dew point and condensation forms • Causes fog and clouds • Caused by • Frontal lifting: when warm air mass rises over a cold air mass OR a mass of cold air slides under a mass of warm air • Orographic lifting: occurs when an obstacle, such as a mountain range, forces a mass of air upward • One side of mountain gets hardly any precipitation • The other side gets plenty of precipitation

9. Dew, Frost and Fog • Dew and frost: • Form when air temperature drops below the dew point, condensation forms • This can cause water on surface to be cooler than the dew point • Water vapor then condenses onto the grass as dew • Fog: • forms when moist air at or near Earth’s surface cools to its dew point • Ground fog: radiation fog • As earth’s surface cools the water vapor near it cools to dew point • Sea fog: advection fog • When warm, moist air moves across cold water and is cooled to its dew point • Steam fog: • When evaporation takes place into cold air that is lying over warmer water

10. Clouds • Read U4L2 pages 164-173 • Main characteristics • Clouds: a collection of small water droplets or ice crystals that are suspended in air • How are they formed? • Clouds form when water vapor condenses or changes from a gas to a liquid • Water condenses when air cools to dew point AND water molecules need a solid surface in which to condense • Cloud condensation nuclei: are the surfaces on which water droplets condense (dust, salt, soil, smoke, etc.)

11. Clouds • Visible because they reflect light • Most do not produce precipitation • Affect temperature • Thick, low-altitude clouds reflect more light and cool the Earth • Thin, high-altitude clouds absorb energy from Earth and reflects it back to warm Earth

12. Cloud shapes • Stratus clouds • Thin and flat, no clear edges • Stratus in Latin means “layer” • Light mist or drizzle may come from these clouds • Fog is a type of stratus cloud that forms at or near the ground • Cumulus clouds • Thick and puffy on top, generally flat on the bottom • Cumulus means “heap” in Latin • Well-defined edges and change shape quickly • Fair-weather cumulus clouds are bright white • Dark cumulus clouds produce thunder, lightening, and heavy precipitation • Cirrus clouds • Feathery and curl at ends • Cirrus means “curl” in Latin • Form high in atmosphere where there is little water vapor and it is very cold • Don’t produce precipitation

13. Clouds based on Altitude • Low clouds • Stratus, stratocumulus, and nimbostratus • Made from water droplets • Middle clouds • Altocumulus and altostratus • Mostly made from water droplets • High clouds • Cirrus, cirrocumulus, and cirrostratus • Made of ice crystals • Vertically developed clouds • Cumulus and cumulonimbus • Linked to sever weather and produce rain, hail, lightning, tornados, and dangerous rapidly sinking columns of air that strike Earth

14. What effects weather • Unit 4 Lesson 3 pages 180-191 • Water cycle • Air masses • Fronts • Pressure • Wind patterns • Jet Steams • Ocean Currents

15. What effects weather • Water Cycle: the continued movement of water between the atmosphere, the land, the oceans, and living things • Evaporation: liquid water to water vapor (gas) • Condensation: water vapor cools and changes from a gas to liquid; forms in clouds • Precipitation: rain, snow, sleet, or hail

16. What effects weather • Air mass: a large volume of air in which temperature and moisture content are nearly the same throughout • Forms when a large mass of air stays in one location above Earth and takes on the Earth’s temperature • When the mass moves, it can change temperature and humidity as it moves to a new area

17. What effects weather • Fronts: a boundary that forms between a cool (more dense) and warm (less dense) air masses • The density difference keep them from mixing • Types of front that forms depends on the way the fronts move relative to each other and the temperature and moisture contents • Types of fronts • Cold front: cold air moves under warm air • Warm front: warm air moves over cold air • Stationary fronts: cold and warm air stop moving

18. What effects weather • Pressure: • High-pressure system: air sinks slowly down; as the air nears the ground, it spreads out toward areas of lower pressure • Most are large and change slowly • When it stays in one location for a long time an air mass can form • Produce clear weather • Low-pressure system: air rises and so has a lower pressure than the areas around it, as the air in the center of an air pressure system rises, the air cools • Produce rainy weather

19. What effects weather • Wind patterns: caused by unequal heating of the Earth’s surface, which cause different air pressures, can occur locally or globally • Local level: air pressure differences affect wind speed and direction • Global level: there is an overall mov’t of surface air from the poles to the equator • Coriolis effect • Easterlies, westerlies, trade winds, equator, horse latitudes

20. What effects weather • Jet streams: long-distance winds that travel above global winds for thousands of kilometers • Moves at speeds of 92 km/h • Flow in a wavy pattern from west to east • between 7 km and 16 km above Earth’s surface • Each hemisphere has a main jet streams, so 2 major ones • Polar jet stream • Subtropical jet stream

21. What effects weather • Ocean currents • Global winds also create surface currents • Ocean currents move energy as heat to different parts of the globe • Warm currents from equator travel to cooler areas of the globe (heat moves from hot to cold) • Cool ocean currents lower coastal air • Warm ocean currents raise coastal air • Also creates hurricanes and monsoons • Warm ocean water= hurricanes • Monsoons are winds that change direction with the seasons

22. Lightening and Thunder • Read U4L4E pages 194-205 • Lightning: an electric discharge that happens between a positively charged area and a negatively charged area • Happens from ground to clouds or b/w clouds • Thunder: sound created by the rapid expansion of air along a lightning strike • The high temperature of air in the path of lightning causes a quick expansion of particles • The particles vibrate and create sound

23. Demonstrate how to read/interpret a weather map. • Read U4L5 pages 208-219

24. Major Weather Measurement Instruments • http://prezi.com/7ewct8k5vfct/the-6-major-weather-instruments/