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GEOGRAPHY OF THE PHYSICAL ENVIRONMENT: Air and Water

GEOGRAPHY OF THE PHYSICAL ENVIRONMENT: Air and Water. 1. Overview - Context "Everyone talks about the weather, but no one does anything about it." (widely attributed to Mark Twain) “Barometer, n.: An ingenious instrument which indicates what kind of weather we are having.”

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GEOGRAPHY OF THE PHYSICAL ENVIRONMENT: Air and Water

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  1. GEOGRAPHY OF THE PHYSICAL ENVIRONMENT: Air and Water 1. Overview - Context "Everyone talks about the weather, but no one does anything about it." (widely attributed to Mark Twain) “Barometer, n.: An ingenious instrument which indicates what kind of weather we are having.” Ambrose Bierce (1842 - 1914), The Devil's Dictionary “Time for the weather report. It's cold out folks. Bonecrushing cold. The kind of cold which will wrench the spirit out of a young man, or forge it into steel.” Diane Frolov and Andrew Schneider, Northern Exposure, 1992 “Weather forecast for tonight: dark. Continued dark overnight, with widely scattered light by morning.” George Carlin (1937 - )

  2. GEOGRAPHY OF THE PHYSICAL ENVIRONMENT: Air and Water Weather and climate maps recognize a geographic concern at many levels: • dispersion of waste gases: http://airnow.gov/index.cfm?action=airnow.displaymaps&Pollutant=OZONE&StateID=60&domain=super • global warming • ozone depletion http://exp-studies.tor.ec.gc.ca/e/ozone/real.htm for real time maps • prediction of forest fire risk: Lawson, O.B. Armitage, W.D. Hoskins 1996 Diurnal Variation in the Fine Fuel Moisture Code http://www.for.gov.bc.ca/hfd/pubs/Docs/Frr/Frr245.htm • whether to go flying/sailing/camping/picnicking/ice fishing... http://www.theweathernetwork.com/ http://weatheroffice.ec.gc.ca/canada_e.html • atmospheric hazards (e.g. for transportation) • choosing where to live or locate an enterprise: ski centres, resorts, hang gliding, airports, crops.. • building design • snow removal budgeting...

  3. GEOGRAPHY OF THE PHYSICAL ENVIRONMENT: Air and Water Meteorology is concerned with the instantaneous condition of atmosphere, as related to physical laws, Climatologyaddresses atmospheric conditions generalized over time, often referred to as “normals”. Both deal with the same atmospheric attributes: temperature, moisture, wind speed and direction etc, but the focus, concepts, methods and applications differ. Both are spatial sciences. Subjects of careful systematic observation (including routine measurement) effects of human activities can only be appreciated if there is understanding of the natural context of atmospheric properties because the atmosphere is global, the actions of anyone and everyone have implications for all of us; everyone has both an interest and responsibility in atmospheric management.

  4. GEOGRAPHY OF THE PHYSICAL ENVIRONMENT: Air and Water Based on measurements from weather balloons (radiosondes), aircraft, and spacecraft, the profiles of atmospheric properties show clear dependencies on elevation. See Chapter 1 of O’Hara et al, 2005.

  5. GEOGRAPHY OF THE PHYSICAL ENVIRONMENT: Air and Water • The atmosphere’s temperature profile : • four layers defined by the nature of the dependency upon height. • lower temperatures at higher locations, (called lapse) typically exists near the earth’s surface • above this, higher temperatures at higher locations, (called inversion) • then the pattern repeats itself.

  6. GEOGRAPHY OF THE PHYSICAL ENVIRONMENT: Air and Water • The composition of dry air varies little: • Nitrogen (N2) dominating (78% of dry air). • Oxygen (O2, plus O and O3) comprising 21% of dry air • The remaining 1%: • Argon (Ar) • other trace elements • greenhouse gases: CO2 (carbon dioxide), CH4 (methane) • various oxides (SOx and NOx) • radio-isotopes (Strontium, Sr and Cesium, Ce) • chlorofluorocarbons (CFC) • particulates /aerosols • See O’Hare et al ,2005, p 10 for more precise concentrations • water vapour (H2O) content may vary considerably in time and space, between nearly 0 and about 4% • Water exerts a dominant influence on the behaviour of the troposphere; • especially important in storing latent heat as water is melted or evaporated and releasing it when condensation or freezing occurs.

  7. Electromagnetic Spectrum

  8. Max Planck (1900) determined that an object (black body) at a given temperature emits (radiates) a characteristic continuous spectrum of energy. Laws related to these emissions have come to be recognized: • °K = °C-273.15; • Tsun = +6000°K; • Tearth= + 300°K)

  9. Energy Cycles Obviously, there are well-known short-term cyclical patterns, and longer periodicities have also been discovered: • Diurnal, with rotation of the earth producing a solar noon • Annual, with the tilt of the earth’s axis relative to the plane of the ecliptic producing shorter and longer day lengths • solstices – north pole points to sun • (summer June 22) or away (winter Dec 22) • equinox – axis orthogonal to plane (vernal March 22, autumnal Sept 22) http://www.archaeoastronomy.com/2011.html • Orbital eccentricity: • • perihelion – orbit is closest to the sun (147.5 million km) January 3-4 • • aphelion – orbit is furthest from the sun (152.5 million km) July 3-4 • longer-term extra-terrestrial patterns (to be discussed in conjunction with climatic variability and change)

  10. Atmospheric Depletions • atmosphere appears transparent, but in fact there are impediments to radiation that affect the transmission of energy (water droplets, water vapour, dust, smoke) • reflection, absorption, and diffusion (sky appears blue, and light is detected before dawn and after sunset) • affects both incoming short-wave and outgoing long-wave • accounted for in energy budgets • selective absorptions do take • place in specific, generally • longer wavelengths, • corresponding to the • atmospheric effects of gases • such as O2, O3, CO2, CH4, and • H 2O. absorption After Fleagle and Businger (1963)

  11. Radiation Balance • incoming shortwave is converted to outgoing longwave at terrestrial surfaces if it has been absorbed and re-emitted • inhibition of outgoing longwave radiation by the opacity of the atmosphere (reflection, absorption, diffusion) causes buildup of heat within the earth-system: Greenhouse Effect (though convection is what greenhouses actually suppress!) • heat is conveyed by three processes: • radiation (electromagnetic waves) • conduction (direct contact) • convection (movement of the heated medium) • Thermal conductivity is the speed at which heat is lost/gained across a thermal gradient (Wm-1, when ΔT = 1°̊Km-1) • • still air 0.025 • turbulent air 3500 to 35 000 • • water 0.6 •turbulent water 350 • • ice 2.24 • • sand .25 - 2.4 • clay .25 - 1.8 • organic soil 0.2 - .21

  12. Radiation Balance Depletions • Outgoing terrestrial radiation • = heat • Incoming solar radiation • = light • light absorbed by the earth, • released as heat

  13. Energy Balance at the earth’s surface; Net incoming energy: • QN = QE + QH + QG • QE • heat lost or gained as water changes state, without raising temperature • • - loss if latent heat used in melting/evaporation • • + gain if latent heat released in condensation/freezing • • QE = 590 calg-1 for vaporization; 80 calg-1 for fusion. • QH • heat lost to raise the temperature of the adjacent air = sensible heat • • felt as temperature of the air • • (volumetric) heat capacity depends on materials, but for air = 0.0012 megajoulesm-3(K̊)-1 • QG • soil or ground heat– temperature below the radiated surface • (volumetric) heat capacities (specific heat is per unit mass): • • water = 4.18 megajoulesm-3(K̊)-1 • ice 1.93 • • sand 0.9 - 2.7 (dry to wet) • clay 1.1 - 3.0 • organic soil 0.2 - 2.1

  14. Diurnal Temperature Pattern

  15. Spatial Patterns Land heats more rapidly and more intensely than water; moist soils have transitional rates

  16. Spatial Patterns Dry, open surfaces cool at night due to longwave radiation losses which are diminished if there is cloud or tree cover, and adjacent to buildings, topographic gradients, or under conditions of high humidity

  17. Energy Balance Applications Management of the energy budget ranges from autonomic responses, to community design. Applications include clothing design, architectural considerations for room comfort and efficient energy management in buildings, landscape and neighbourhood planning, agricultural practices to reduce frost risk and to ameliorate cold soils Due to autonomic reactions (tolerance) we and other life forms have survived despite the range of variations normally found in the atmosphere. Especially dramatic are temperature changes; selective survival has favoured those with autonomic reflexes triggered by heat or by cold to promote homeostasis - the ability to maintain a steady state: personal adaption (shiver or sweat), cultural responses (huddle or ceiling fans), physiological adaptations (survival of predisposition to tolerate or accommodate cold (short, chubby) or heat (lank). Avoiding Hypothermia – abnormally depressed body temperature

  18. from Lee, 1958 (in Oliver, 1973, p198))

  19. Core body temperature: 37°C • When stressed beyond critical limits results become threatening Cooling can be used in patients who have been resuscitated from cardiac arrest, however: Hypothermia (abnormal low-heat stress): • Inadequate insulation in exposure to an extreme and prolonged cold environment (air or water) core temperature only falls to 35°C • 911 • Rest in a sheltered, warm, dry environment, wrapped, including the head, monitor breathing, gradual warming of the wraps on trunk, • cool place; drink water or fruit/vegetable juices (avoid alcohol and caffeine); shower or bathe, or sponge off with cool water; lie down • Groups at risk: very young and very old, already compromised judgment (alcohol, and drugs, some medications, and/or medical conditions.

  20. Fever naturally fights invasive organisms (infection); Hyperthermia is regarded as a promising approach in cancer therapy; however: Hyperthermia (abnormal heat stress): • Heat exhaustion: perspiring, thirsty, lightheaded, headache, nausea, diminished co-ordination, and fatigue (weakened pulse) [consult a doctor] • Heat stroke: confusion, combativeness, faintness, staggering, strong rapid pulse, dry flushed skin, lack of sweating, possible delirium or coma, failure of systems: cardiac arrest, brain damage; almost always results in death (U. S. National Institutes of health, 1989 http://www.nia.nih.gov/health/agepages/hyperthe.htm) • 911 • Rest in a cool place; drink water or fruit/vegetable juices (avoid alcohol and caffeine); shower or bathe, or sponge off with cool water; lie down • Groups at risk: elderly, some medications, compromised internal organs or sweat glands, overweight, consumption of alcohol

  21. Energy Balance Applications (personal, buildings, societal) Personal: autonomic responses suggest inherent need to manage our environment - at least the ambient conditions; skin temperature is lower than core ~19̊C • care in selecting/designing of clothing (fashion, survival suits, construction safety vests); for cooling (loose, lightweight) when hot, or for holding in warmth when cold (layers of insulating air): • human Comfort Zone is not determined by temperature alone; the relative humidity (humidex), air speed (enhanced evaporation or wind chill), direct solar radiation all disguise the actual temperature we feel • Less than 29: No discomfort • 30 to 39: Some discomfort • 40 to 45: Great discomfort; avoid exertion • Above 45: Dangerous • Above 54:Heat stroke imminent

  22. Health and Safety Applications: • Ottawa-Carleton District School Board, 1999, Extreme Weather Conditions – Guidelines http://www.ocdsb.edu.on.ca/PDF%20files/Policies_and_Procedures/Procedures/PR%20581%20HR%20Extreme%20Weather.pdf • Ontario Ministry of Labour – heat stress http://www.labour.gov.on.ca/english/hs/pubs/gl_heat.php • Treasury Board of Canada, 1992, Occupational Health and Safety - Use and occupancy of buildings directive http://www.njc-cnm.gc.ca/doc.php?did=391&lang=en • 20 ̊C-26 ̊C is the ideal temperature operating range • 17 ̊C-20 ̊C and >26̊ C can be uncomfortable, occupancy should not exceed 3 hours daily or 120 hours annually in each of these extremes • >26 ̊C is uncomfortable when the humidex ≤40 ̊C • operations shall be stopped and employees released from the workplace

  23. Wind Chill: Graphing temperature by wind speed shows actual rate of heat loss from exposed skin: “feels like” (calm conditions and same heat loss) • e.g. 1000 cal/m2/hour is lost when temperature is -10̊C at a wind speed of only 2m/sec and +4̊C at a win dspeed of 17 m/sec • ∴ heat loss for low temperature when calm is the equivalent of a higher temperature when windy

  24. Buildings (Thermal Conductivities: the speed of heat loss (if △T = 1 K ̊m-1) e.g. still air 0.025 Wm-1, moving air 3500 to 35 000 Wm-1) Poor thermal conductors are good insulators, so there are at least three classes of building materials: • Buildings can take advantage of the inherent insulating capabilities of these materials, however…

  25. The most important aspect of modern building Energy Efficiency is to prevent air exchange (convective transfer) Current practices involve: • sealing doors and windows • special glazing solutions (shades outside windows, film to inhibit uV radiation) • confining air spaces in walls • as greenhouses function: • incoming solar radiation is unimpeded • outgoing terrestrial radiation is impeded, producing net energy gain • ventilation (convection/advection) is used to manage the actual temperature within the desired comfort zone

  26. Passive Solar Heating • energy conservation aimed correcting at unsustainable dependency on fossil fuels. • deciduous trees offer summer shade, if planted on the south face of houses • transmit winter sunlight to the glass wall for absorption inside the building • reflective and insulating retractable blinds can be positioned for maximum light absorption and minimum long wave loss • dark internal walls absorb winter sun and act as a “black body” heat sink, with emitted long wave radiation providing room heating during darkness • earth berms and evergreens on the north (and west) can minimize winter heat loss, by diminishing convective mixing of air

  27. Passive solar heating: • deciduous trees on the south face • glass wall on the south face • reflective and insulating retractable blinds • dark internal walls and surfaces • earth berm on the north • evergreens on the north 3 1 6 2 5 4 N S

  28. Societal applications • planning for passive and active heating for energy efficiency and sustainability • mapping insolation (annual megawatt hours /m2) indicates : • on a daily basis the wattage available is limited • much of it is received when it is needed least (warm summer days) • efficient means of storage is necessary.

  29. passive and active applications especially in remote (dispersed-demand) areas: • farm building architecture • including windbreak design • Farmers also manage micro-meteorology in order to prevent frost • misting fields on cool nights (LE given off as water freezes prevents blossom or crop damage) • smouldering “smudge” pots to put smoke particulates into the air, to re-radiate longwave radiation downward and inhibit overnight frost • cold soils are also ameliorated by regrading to allow colder air to drain downslope, removing low patches and adjacent “dams” on cold air drainage • Landscaping and neighbourhood design / community planning for energy efficiency • lighting • heating • elevation effects • floor plans • wind breaking / snow drift control

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