视听阅读第二册 Unit 10 How Is the Weather.ppt

Book 2 Unit 10 How’s the Weather? Background Information The weather on Earth is always changing. One day it’s cloudy, the next day it’s sunny, and the day after that- who knows? Meteorologists are scientists that can predict the weather. But how do they do it? What causes these changes in weather? Greenhouse Effect Means “natural” process keeps the Earth warm and habitable, and protects life. Means “man-driven” greenhouse effect, increases the natural effect artificially by emitting greenhouse gases from fossil fuel burning and by deforestation. Greenhouse Gas Absorb infrared radiation radiated from the earth Make the atmosphere warmer that it would be Act as “blanket”, Warms the lower layers of the atmosphere Keeps the upper layers colder Water vapor: 80-90% of the Earth’s natural greenhouse gas The remainder is due to co2, methane, minor… Causes of Global Warming Natural forces “Human-driven” portion Burning of fossil fuels Industrial Revolution, human activities, … More and more are released into air Human Activities Burning natural gas, coal and oil (gasoline) Agricultural practices and land-use Long-lasting industrial gases Deforestation Population growth Warming Up I. Earth and Its weather Hail, thunderstorm, sandstorm, snowstorm, tornado, typhoon II. Predicting the Weather Meteorologist, prediction, Radar, meteorology, front, forecast, thermometer,satellite Part I I. B,C,E,F II. C,A,E,D,B A cold front: B, C A warm front: A, C, D III. Heat up, cause, rise, drop, flow, interact with, exchange, create Part II I. B II. 1. the atmospheric conditions 2. air pressure, humidity, clouds, precipitation 3. barometers, complicated, measure the conditions 4. nice weather, storms Part III I. C,D,A,B when to plant and harvest crops their planes can reach their destinations quickly and safely II. Ice crystals, water drops, hail, sleet, snow, updraft Part IV 1-G, 2-D, 3-A, 4-B, 5-C, 6-F, 7-E Reading D,C,B,C,C,B,D Vast weather engine, Violent storms Th