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Chapter 17 Atmosphere and Weather Atmo = vapor Cirru = hairlike curls Strat = layer Cumul = heaped Alto = high Iso = equal Nimb = light (quick) Baro = weight Hygro = moist Meso = middle Trop = turn Therm = heat Weather = constantly changing; refers to the state of the atmosphere at any given time and place. Climate = weather patterns based on long periods of time; describes a place or region. Composition of the Atmosphere Major Components: • • • • • Nitrogen (78%) Oxygen (21%) Argon Carbon Dioxide All Others Composition of the Atmosphere Variable Components: • Water Vapor • Ozone • Pollution Air Pollution http://svs.gsfc.nasa.gov/vis/a01 0000/a010000/a010012/ Ozone Recovery http://www.amnh.org/sciencebulletins/ Temperature and Altitude Pg 480 Fig 6 How far does our atmosphere extend? Earth Moon Types of Clouds Check Yourself! Height and Structure of the Atmosphere Pressure: Weight of air above. Closer to Earth’s surface = more pressure. Barometer = measures air pressure Wind Speed Measured on the Beaufort Scale Relates wind speed to its effects Wind chill factor Anemometers Sir Francis Beaufort Relative Humidity Hygrometer Measures the amount of moisture in the air Meteorology Meteorologists study weather How atmosphere heats and cools How clouds form and produce rain What makes wind blow Composition of atmosphere Cause of past and present climates http://www.youtube.com/watc h?v=uYctRlQ0gOE&feature=rela ted Seasons Sun’s rays do not strike surface evenly Solstice vs. Equinox Earth-Sun Relationships Earth’s Motions • Rotation = spinning on its axis • Revolution = movement around the sun Rotation 23.5o Tilt Seasons are a result of the tilt of Earth’s axis remaining the same as the Earth revolves around the sun. Revolution Vernal Equinox Days begin getting longer. Vernal Equinox March 21 Summer Solstice First official day of Summer. Autumnal Equinox Days begin getting shorter. Winter Solstice First official day of Winter. Winter Solstice Dec 21 Summer Solstice June 21 Autumnal Equinox Sept 22 DAYLIGHT Spring and Fall Equinox: All latitudes receive 12 hours of daylight. Vernal Equinox March 21 Summer Solstice: Northern latitudes receive 24 hours of daylight. Winter Solstice: Northern latitudes receive 24 hours of darkness. Winter Solstice Dec 21 Summer Solstice June 21 Autumnal Equinox Sept 22 Radiation and Earth’s Atmosphere INCOMING RADIATION 100% 8% 17% OUTGOING RADIATION 6% 9% 40% 20% 19% 4% 6% 46% 15% 7% 24% Earth Temperature At night, heat from the day is released from the Earth. Solar radiation is absorbed from the sun during the day. Clear night skies Partly cloudy night skies Cloudy night skies Solar Radiation Reflection = radiation is sent back to space. Scattering = radiation is broken into smaller rays and scattered. Absorption = radiation is absorbed and retained. Reflection Absorption Earth Temperature At night, heat from the day is released from the Earth. Solar radiation is absorbed from the sun during the day. Clear night skies Partly cloudy night skies Cloudy night skies Discovery Ed: The Greenhouse Effect [14:38] Trapping of the sun’s energy by the atmosphere Caused by Greenhouse Gasses CO2, Methane, CFCs Burning fossil fuels Coal, oil, & natural gas Global Warming! Causes of the Greenhouse Effect http://environment.nationalgeographic.co Eventually we will have a “lid” on our planet! m/environment/global-warming/quizglobal-warming/ Deforestation CFC’s Burning Fossil Fuels Industrial Pollution 17.3 Temperature Controls Factors Affecting Atmospheric Temperature: • • • • • • Latitude Heating of Land and Water Altitude Geographic Position Cloud Cover Ocean Currents Temperatures also become cooler with altitude. Normal Lapse Rate 1° every 160m Temperature Inversion Ground cools faster than air Morning fog Celsius: Fahrenheit: 0° - 100° 32 °- 212 ° Isolines: connect points of equal value on maps Land, Water and Temperature… Land heats and cools more rapidly than water. Page 489 Fig 15 Geographic Position and Temperature… Windward locations are warmer than leeward locations. Page 490 Fig 16 Altitude and Temperature… Higher altitudes are colder than lower altitudes. Page 491 Fig 17 Human Influence and Temperature… Nat Geo Global Warming Shorts http://video.nationalgeographic.com/vid eo/player/science/index.html Cloud Cover, Albedo and Temperature… Albedo = fraction of total radiation that is reflected. Clouds reflect sunlight during the daytime and trap heat from the Earth at night. Disc Ed: Clouds and Patterns of the Weather [21:00] World Temperatures Isotherms = lines that connect points that have the same temperature.