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2-1 Atmospheric Environment I slides

2-1 Atmospheric Environment I slides - Earth’s Earth’s...

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Unformatted text preview: Earth’s Earth’s Environmental Systems Systems II & Atmospheric Environment ENV200H1S – February 1 2011 eb 1 Announcements Announcements Tutorial #2 – Fair Share of Resources (Tragedy of the the Commons) start next week Worksheet posted Calculate ecological footprint Read 3 articles & answer questions: Go forth, multiply and fill the provinces Does helping the planet hurt the poor? No, if the West makes sacrifices Does helping the planet hurt the poor? Yes, if if we listen to green extremists 2 Outline Earth’s Environmental Systems Biogeochemical cycles Atmospheric Environment, p. 340-348 340 El Nino Southern Oscillation (ENSO), p. 322322-324 Thursday – Global Climate Change, p. Thursda 368368-382; Ozone Depletion, 383-386 383- 3 Biogeochemical Biogeochemical Cycles Matter cycles through ecosystems Carbon Hydrologic (water) Nitrogen Phosphorus 4 Carbon Cycle Essential component for life Gas (CO2) in atmosphere Several forms in ocean Can take a long time—think fossil fuels me— Photosynthesis CO2 Cellular respiration Sugar CO2 5 Carbon Carbon Cycle 6 Hydrologic Cycle Ocean Atmosphere Land Ocean 7 Nitrogen Nitrogen Cycle Proteins, DNA DNA Atmosphere is 78% N2 Five steps Nitrogen fixation Nitrification Assimilation Ammonification Denitrification 8 Nitrogen Nitrogen Fixation Specialized bacteria Split atmospheric nitrogen and combine it with hydrogen ith h d 9 Nitrogen Nitrogen Cycle 10 Nitrogen Nitrogen Cycle take home messages Human activites have significantly influenced activites nitrogen nitrogen cycle In early 20th C, chemical advances allowed chemical almost almost unlimited supplies by converting atmospheric nitrogen to ammonia (a more biologically useable form Projected that amount of nitrogen deposition on Earth’s Earth’s surface will double within next 25 years. Eutrophication, water quality, smog, acid Eutrophication, rain, rain, greenhouse gases 11 Ph Phosphorus Cycle No atmospheric component Phosphates used in DNA and ATP (chemical (chemical energy) Phosphates move through the food chain Land Organism Organism Land 12 Ph Phosphorus Cycle 13 Phosphorus Phosphorus Cycle Patchy distribution When trapped in lithosphere may stay there for extended periods, e.g. Ocean there Ocean floor floor for millions of years Traditionally a limiting factor that can prevent prevent growth, distribution or abundance abundance Overabundance can have many interconnected impacts 14 The Atmosphere 15 The Atmosphere Gaseous envelope surrounding Earth Mostly oxygen & nitrogen (99%) Four layers Troposphere Stratosphere Mesosphere Thermosphere 16 The Atmosphere 17 Atmospheric Atmospheric Temperature Changes 18 19 19 20 20 What’s In Our Atmosphere Nitrogen Oxygen Argon Carbon dioxide Other Gases 78% 21% 0.93% 0.04% 0.03% 21 The Atmosphere Ecosystem services Protects Earth from UV radiation Allows visible light and some infrared li h to to penetrate We depend on the atmosphere Oxygen balance 22 From From our sun’s energy output and our distance distance from it you would predict that that Earth should have a temperature of -18o C: 18 Yet, Earth’s global average temperature is about about + 15o C What factors account for the ‘extra’ 33oC? Nature of EMR and its various fates Composition of the atmosphere, Composition hydrosphere, hydrosphere, lithosphere 23 Solar Radiation and Atmospheric Circulation Electromagnetic spectrum Entire range of electromagnetic radiation includes gamma, x-ray, ultraviolet, visible, ra infrared, microwave, and radio Gamma, x-rays and most UV rays are absorbed xby the stratosphere Plants use portions of visible light for photosynthesis photosynthesis 24 Solar Solar Radiation Visible light passes through atmosphere undiminished. Ultraviolet light is absorbed by ozone in the stratosphere. Infrared radiation is absorbed by carbon dioxide and is water water in the troposphere. troposphere. 25 The The different wavelengths comprising the EMR spectrum that comes from the sun 1 mm mm cell phones phones Low energy, long λ High energy, short λ 26 Behaviours Behaviours of EMR When wavelength When a wavelength of EMR moves out of the the vacuum of space and enters the atmosphere, a number of things could happen: (1) nothing (transmission) (2) reflected (off dust, clouds, etc.) etc (3) (3) absorbed (by water vapour, oxygen, oxygen, the oceans, land masses, etc.) etc 27 reflection transmission Absorption of high energy λ = 28 rere-emission of lower energy λ + heat Numerous Numerous substances can absorb absorb EMR land masses water (significant given that 70% of Earth is ocean) various gases in the atmosphere (O2, H2O, CO2) Th The physicochemical properties of each of these substances substances determines which λ are absorbed. This is particularly true of different gases in the atmosphere atmosphere which means the surface of the Earth is exposed to a substantially modified spectrum of EMR when compared to what came EMR in in at the top of the atmosphere (from the sun). 29 Earth’s Earth’s Energy Budget 30 The The Sun & Latitude Sun does not reach all places uniformly: wh ? l hy Temperature varies locally 31 The The Seasons Inclination on its axis determines Earth’s seasons seasons N. and S. hemispheres are opposite 32 ...
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