Atmosphere Thin envelope of gases that surrounds the planet. Weather Climate Weather conditions at a locality averaged over a specified time period The state of the atmosphere at a given place and time Study of weather and climate Meteorology
Layers of Atmosphere Exosphere (outer space) Ozone Layer Weather occurs
Troposphere • Layer closest to our earth • Extends to a height of 8-15 kilometers (5-9 miles) • Temperature ranges from (63° to -62°F) • Weather occurs here • A very large thunderstorm could extend into the next layer of the atmosphere • The air that we breath • Can contain air pollution, bad ozone, smog
Stratosphere • 2nd layer of the atmopshere • Ozone layer (good ozone) that shields us from harmful radiation from the sun • Temperature increase as you go up through the atmosphere • Temperature is (27°F).
Mesosphere • 3rd layer of the atmosphere • Meteorites burn up in this section • Coldest layer
Thermosphere • 4th Layer of the atmopshere • UV radiation is absorbed • Shooting stars • Hottest layer
Natural Atmosphere ProcessesOzone Shield in the Stratosphere • Ozone shield is needed to filter out the sun’s UV radiation. 95% filtered • The ozone shield protects humans from skin cancer, sun burns, eye cataracts, and damage to the immune system • Prevents the oxygen in the troposphere from being converted to photochemical ozone
What causes ozone depletion?CFC • CFC—chlorofluorocarbons • CFC-11 trichlorofluormethane, CFC-12 dichlorodifluoromethane also known as freons • Odorless, colorless, nontoxic, nonreactive, nonflamable, noncorrosive • Cheap • Used a coolants for air conditioners, refrigerators • Used as propellants in aerosol spray cans • Cleaners for computer chips • Fumigants • Insoluble to water so they remain in the atmosphere • Each molecule can last 65-385 years • Each chlorine atom converts ozone to oxygen
Add this to the bottom of your sheet Gases in Atmosphere • Nitrogen (78%) & Oxygen (21%) • Carbon dioxide & others (trace amounts)
3 methods of energy transfer: • Radiation= transfer of energy through space by visible light, UV light, and electromagnetic waves EX: sun • Conduction= transfer of energy when molecules collide EX: metals • Convection= transfer of energy by flow of a heated substance EX: water, air
Humidity vs. Relative Humidity • Humidity= amount of water vapor in the air • Relative Humidity= ratio of water vapor in the air relative to how much water vapor the air can hold • 0% very dry • 90% very wet (rain is near)
Relative Humidity • The relative humidity tells us how “full” the air is at the time of measurement. • For example, 90% relative humidity means that at that moment the air is holding 90% of the maximum amount of water it could.
Relative Humidity • Measure of water vapor in the air. • Instrument = Hygrometer • If air holds all the water vapor it can, it is at 100% RH and is said to be saturated Warm air can hold more water vapor.
Air Masses There are two types of air masses: 1. Continental Polar air masses 2. Maritime Tropical air masses
Coriolis Effect • http://www.classzone.com/books/earth_science/terc/content/visualizations/es1904/es1904page01.cfm Animation • Particles are deflected in the Northern Hemisphere to the right and in the Southern Hemisphere to the left.
Trade Winds • The sun warms the air and it rises to 20 to 30 degrees to the South and the North, then is falls back down
Jet Stream • The current of fast moving air • Usually moves from East to West
Fronts A front is the boundary separating air masses of different densities • Fronts extend both vertically and horizontally in the atmosphere
Fronts: Five Types of Fronts 1.Cold Front: The zone where cold air is replacing warmer air • In U.S., cold fronts usually move from northwest to southeast • Air gets drier after a cold front moves through
Fronts: Five Types of Fronts 2.Warm Front: The zone where warm air is replacing colder air • In U.S., warm fronts usually move from southwest to northeast • Air gets more humid after a warm front moves through
Fronts: Five Types of Fronts 3.Stationary Front: When either a cold or warm front stops moving • When the front starts moving again it returns to either being acoldor warm front
High and Low Pressure Areas • High pressure causes air to sink • Usually results in several days of clear sunny skies • Air rises in low pressure areas and forms water droplets • Usually results in rain and storms
Temperature and Thermometer • Measurement of how rapid or slow a molecule move around • Measured by a thermometer • Units • Fahrenheit (°F) • Celsius (°C) • Kelvin (K)
Wind Direction and Speed • Direction is measured with a “vane” • Speed is measured with an “anemometer.”
Pressure and Barometer • Air molecules push down on objects—including us! • Measured by Barometers • Demonstration
Doppler Radar Effect • Doppler Effect is the movement of frequencies going away or toward you as the source moves • Radar measures the amount of precipitation in the air • Doppler Radar
Pressure-Temperature-Density Relationships • As Temperature , Pressure • As Temperature , Pressure • As Temperature, Density **Temperature and Pressure are directly proportionate (goes the same direction) ** Temperature and Density are inversely proportionate (goes in the opposite direction)
What happens in the atmosphere • Most of the time, the temperature and pressure decreases through the troposphere • Sometimes….the atmosphere does not have perfect relationships between temperature, density, and pressure. • Warm Air rises, cold air sinks
Temperature Inversion • When the cold air is on top of the warm air. The warm air can not rise to release pollution. • This can lead to smog and pollution closer to the earth’s surface
Dew Point and Condensation • Temperature at which air must be cooled at constant pressure to reach saturation • Saturation= amount that the atmosphere can hold. • Higher the dew point then condensation (changing gas to liquid) can occur and it can rain.
Heat • Transfer of energy • Hot ALWAYS travels into the Cold
Weather Station Model • Directions: • Read the handout again to understand what each symbol means • Use the chart to draw your own on in your lab book
Weather Maps • From the weather maps, you are going to answer the questions about the maps in your comp book.
Clouds Write this on your own paper for your notes • Turn in your textbooks to page 287 • Draw this chart on the screen • Using your textbook and table 11-3, write what the description and draw a picture of the cloud • When you have finished see me to pick up your construction paper and cotton balls. You will reconstruct the clouds out of the cotton balls. Please label each cloud. • After everyone builds the clouds we will go outside and observe them
Tornado Whirlwind of air on land Measured by Fujita scale F0-F5 Hurricanes Whirlwind of air on water Measured by Saffir Simpson Index 1-5 Tornadoes vs. Hurricanes
Severe Weather • Thunderstorms • All contain lighting, cumulunimbus clouds • Single Cell • Multi Cell • Super Cell violent tornados • May produce flash floods/hail/tornados • Downdrafts damaging winds near surface
Tornados • Violently rotating column of air in contact with the ground • Rotating updraft is a key to the development tornado. • Caused by wind shear 25 mph 5mph
How does lightening form? • Air friction in the clouds • Separate + and – create voltage channel • Lightning kills more people than tornados, hurricanes
What causes thunder? • 30,000 oC air expands • “Explosion of Air” • Light waves travel faster than sound waves
Weak Strong No greater than 110 mph 110 mph – 200mph 200 mph + Less than 2%
Cyclones, Typhoons, Hurricanes??? • All the same thing • All need energy source = warm tropical water
Hurricanes • Tropical cyclones with winds that exceed 64 knots (74 mi/hr) • circulate counter-clockwise • Northern Hemisphere • Clockwise in the • Southern Hemisphere • Water must be warmer than 81 F
Stages of Development • Depression Storm Hurricanes
Extreme Weather Video Clips • http://dsc.discovery.com/videos/wonders-of-weather-extreme-weather.html (extreme weather) • http://dsc.discovery.com/videos/wonders-of-weather-lightning-phenomena.html (lightning) • http://dsc.discovery.com/videos/storm-chasers-science-of-storm-chasing/ (storm chasers)
Hurricanes • http://planetgreen.discovery.com/videos/focus-earth-hurricanes-and-climate-change.html (climate and hurricanes) • http://www.pbs.org/wgbh/nova/sciencenow/3204/02.html (hurricanes)--12 min