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The Atmosphere and Space The Atmosphere gases essential for life layer of air surrounding Earth screen blocking out dangerous rays stable climate by retaining heat O2 for cellular respiration CO2 for photosynthesis Gravity pulls particles toward the planet 99 % of mass of air in first 30 km Really 10 000 km thick 21 % O2 78 % N2 + water vapour + other gases = homogeneous mix Water = relative humidity = cloud formation and ppt Pollution = pollen, soot, smoke, droplets etc 5 layers Air is a compressible fluid Contains particles that collide constantly therefore air pression Greater number of collisions = greater pressure P decreases at higher altitudes Warmer air = faster particles = move away from each other = lower density = rises Air particles move away from hi P areas (lots of P) to lo P areas = winds!! Atmospheric Circulation Air constantly moving in the troposphere Rises at the equator → to the poles → descends = hi P zones → equator Convection = distributes solar E Coriolis Effect = rotation of the Earth = causes winds to deviate from the vertical To the right in the N and to the left in the S Cold fronts, warm fronts and clouds *Prevailing Winds Circulation cells Each hemisphere = 3 cells Major atmospheric currents that blow in a given direction according to global patterns of movement Polar easterlies = pole and 60th parallel Westerlies = middle = 60 and 30th parallels Trade winds = easterlies = btw 30th and equator QC = Westerlies therefore winds move from west to east Jet streams at very hi altitudes = west to east = strong in winter Each hemisphere = 2 jets = Subtropical and polar jet stream = pilots Subtropical jet stream (30th parallel) and polar jet stream (60th parallel) Airplane pilots use and avoid!! Why?? Air Masses A large expanse of the atmosphere with relatively uniform temperature and humidity QC = warm from tropical and cool from polar 2 air masses meet Denser cold air slides beneath the lighter warmer air The line where they meet = a front Warm fronts and cold fronts Cold front Cold air meets warm air Warm air rises rapidly and sharply and then cools Condensation Puffy clouds = cumulus Wind and heavy rain Warm front Warm air meets cold air Rises gently above the cold Creates light clouds of many layers = nimbostratus Cloudy weather and showers Slow to disperse bec warm fronts do not travel as fast as cold front Anticyclones and Depressions Most air masses move horizontally Vertical movements too When air cools the particles move closer tog. Air density increases Air mass heavier Sinks and compresses particles beneath it = area of hi pressure = H When air warms = density decreases = lighter and rises Leaves empty space beneath = low pressure = depression = L Near anticyclones and depressions = Coriolis effect = turning of air Northern Hemisphere = clockwise = anticylclone and counterclockwise = depression Anticyclone = falling particles prevent cloud formation = clear skies = sunny and dry summer and cold winter Depression = rising air = cloud formation = precipitation Strong depressions over warm waters = tropical storms = cyclones, hurricanes or typhoons = torrential rain = floods = landslides etc The Greenhouse Effect (GHE) = natural process = good!!! GHG = water vapour, carbon dioxide, methane and nitrous oxide (dinitrogen monoxide) Always present and Keep in some of the E the earth receives from the sun Most of the sun’s rays reach the earth are absorbed by the ground Once heated the ground emits infra-red rays up into atmosphere and lost in space GHG trap some of infra-red = good = keeps us warm = warm is good = hot is bad!! BUT NOW!!!!!!! Intensify the effect and we’re in trouble!!! Natural emissions of CO2 = volcano, cellular respiration Absorb CO2 by photosynthesis and the ocean dissolving Combustion = main source of CO2 now = billions of tonnes! Global Warming GHE good Global Warming bad Combustion, clearing land for farting cows and farming Climate change = abnormal modification of climactic conditions on Earth, caused by human activity Methane (from farting cows, manure storage and management, rice farming, decomposing household waste and the distribution of natural gas) not as much gas made but….21 x the effect N2O from applying nitrogen-rich fertilizer to farm crops Increase temperature 0.76 oC from 1850 to 2005 ΔT of 2 oC and critical point!! Increase droughts, heat waves, floods and a rise in sea levels The Contamination of the Atmosphere Humans!!!!! Are bad people!!!!! Sulfur dioxide and nitrogen oxides form acid rain and smog Mercury, arsenic and lead from oil and coal combustion = toxic to humans in ppm! Chlorofluorocarbons CFCs destroy ozone molecules = increased UV exposure Dust and airborne particles from chimneys and cars Too high a quantity and react with other chemicals in the atmosphere Not point sources!! Contaminants have an effect far away The Thinning of the Ozone Layer Ozone = O3 = 3 oxygen atoms = a gas 20 to 30 km up!!! = a protective layer of gas Absorbs some UV A chemical filter Late 1970s when I was young!!!! The South Pole hole in the ozone was discovered CFCs used as refrigerants act as catalysts in the destruction of ozone CFC Cl atom is released and it is the catalyst therefore re-used over and over again! 1987 = Montreal Protocol = outlawed here but still used elsewhere Fingers crossed = 2055 and 2065 = restored ozone layer Smog Ozone here at low altitudes Sun’s rays hit nitrogen oxide (from cars) or SO2 (from coal burning) = O3 Thick mixture of fog, smoke and atmospheric pollutants Intensity varies depending on weather conditions and composition Energy Resources Windmills for centuries Wind E to mechanical E transformation Wind Energy E from the wind Wind turbines 120 m in height Activates an electric generator Renewable No GHG Towers ruin beauty Winds are variable Cannot be stored!!!! Used in combination with another source The Effect of the Sun and the Moon on the Earth The sun for Energy The moon’s gravitational pull for tides Solar Radiation Sun = 75 % H and 25 % He 15 000 000 oC at core Nuclear reaction of fusion Solar E carried by electromagnetic waves Takes 8 min to reach earth – 150 million km away!! Contains all the waves in the electromagnetic spectrum from cosmic rays to radiowaves Only visible light, IR and some UV reach us Rays heat the atmosphere, oceans and land Curvature = tropical regions receive more E = equator Temperature differences = atmospheric movements of air and ocean currents Solar Energy Passive heating systems = south facing houses, concrete to absorb and release E Photovoltaic cells = silicon (usually) hit by light = electrons excited and move = current Solar collectors = large glass panels = copper pipes below filled with moving water Costly Variable bec of sun’s position and cloudy conditions Renewable No GHG Isolated areas = Far North or Space! The Earth – Moon System Billions of years = moon revolving around earth ¼ earth’s diameter Meteorite 4.6 billion years ago strikes earth = explodes Moon rotates on its own axis and revolves around earth 27.3 days to rotate and 27.3 days to revolve Tides High tides = bulges of water Water masses closest to the moon are attracted to it Force of attraction = gravitational force Opposite side water is less attracted but earth is attracted to bulge Earth = 24 h to rotate and moon’s position hardly changes the oceans swell twice per day Tidal range = difference btw high and low tides Shape and slope of coastline, depth of water and distance of sun or moon from earth Sun pulls on earth too but to a lesser degree Spring tides = extremely high tides when moon and sun line up and pull on earth Tidal Energy E from ebb and flow of tides Tides fill a basin Difference in water level Gate opens and water flows through turbine Renewable No GHG Perfectly reliable bec meteorologists can pinpoint exactly ebb and flow by studying positions of moon and sun Building plants is complex and costly Few suitable sites Large tidal range necessary at least 5 m