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Midterm

GGR100 Midterm Notes

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Department
Geography
Course
GGR100H1
Professor
Jennifer Weaver
Semester
Summer

Description
GEO100 COURSE NOTES Chapter 1 – Essentials of Geography (Tuesday May 17 )h Physical geography = spatial analysis of all the physical elements and processes that make up the environment: energy, air, water weather, climate, landforms, soils, animals, plants, microorganisms, and Earth itself Geography = relationship among natural systems, geographic areas, society, cultural activities, and the interdependence of all of these over space  Spatial = nature and characteristic of physical space, its measurement, and the distribution of things within in (ex. Route to class includes knowledge of street patter, traffic trouble spots, bike rack locations, etc)  Humans are spatial actors, both affecting & being affected by the earth  5 main themes: location, region, human-Earth relationships, movement, place Scientific Method  Real world (Perception) → Observations/Measurements (Data collection, acquisition, observation) → Inductive Reasoning (explanation analysis, interpretation) → Hypothesis (search of patters/orders/process) → Predictions (Experiment & testing, verification) → General Theory/Governing Laws (Theory Formulation) Geographic Analysis  Governed by method of ‘spatial analysis’  Depend on earth’s system to provide: oxygen, water, nutrients, energy, and materials to support life Earth Systems Concept  Systems Theory = is any ordered, interrelated set of things and their attributes, linked by flows of energy and matter, as distinct from surrounding environment outside the system o Open Systems = not self contained: inputs of energy and matter flow into the system, and outputs of energy and matter flow from the system ex. The body, plants, cars, etc) o Earth is open system in terms of energy (solar energy enters, changes into kinetic, potential or chemical and earth radiates heat energy leaves back to space) o Closed Systems = self contained, shut off from surrounding environment o Earth is closed system in terms of physical matter and resources  Systems Feedback = system’s outputs influence its own operations o Outputs function as ‘info’ that returned to various points in the system via pathways called Feedback loops o Ex. ↓/↑ sunlight/CO 2H O2affects photosynthetic system => causing changes in growth process o Feedback information discourages response in system = Negative Feedback  Cause self regulations in natural system, stabilizing and maintaining systems o Feedback information encourages increased response in system = Positive Feedback  Unchecked growth will reach a critical limit, leading to instability, disruption or death of organism  Ex. Good review of movie, compound interest, fires, melting of glaciers o System Equilibrium = energy and material system balanced, rate of inputs and outputs are equal and amounts of energy and matter in storage within the system are constant (ex. Body weight)  Steady-state equilibrium = fluctuates around steady average  Dynamic equilibrium = increasing or decreasing system operations (steady change over time), tend to resist abrupt change, but may reach threshold/tipping point where it change into a new operation (this abrupt change is called ‘metastable equilibrium) new equilibrium eventually reached  Ex. Hillside after landslide o Model = simplified, idealized representation of part of the real world.  Earth’s Four Spheres o 3 abiotic (non-living) systems overlapping to form the realm of the biotic (living system) o Atmosphere = thin gaseous veil surrounding the earth, held to the planted by gravity, formed by gases arising from within the Earth’s crust and interior and the exhalations of all life over time o Hydrosphere = Earth’s waters exist in the atmosphere, on the surface, and in the crust near the surface, frozen portion called ‘cryosphere’ o Lithosphere = earth’s crust and portion of the upper mantle directly below the crust o Biosphere/Ecoshpere = intricate interconnection web that links all organisms with their physical environment, 3 overlapping abiotic systems  Spherical Planet o Geoid = shape of Earth is earth shaped o Latitude = angular distance north or south of the equator measured from the center of Earth, parallel lines to equator, 49°  Determined by observing fixed celestial objections, sight Polaris and measure angel to horizon  Zones: equatorial and tropical (23.5°N – 23.5°S), subtropical (23.5°N/S – 35°N/S), midlatitude (35°N/S - 55°N/S), subarctic/subantarctic (55°S/N – 66.5°N/S), arctic/Antarctic (66.5°N/S - 90°N/S)  Notable: Tropic of Cancer (23.5°N), Tropic of Capricorn (23.5°S), Arctic circle (66.5°N), Antarctic circle (66.5°S) o Longitude = angular distance east of west of a point on Earth’s surface, measured from the center of the earth  Line connecting all points along same longitude is a ‘meridian’  Prime Meridian = 0°, passes through Greenwich, England o Great Circle = any circle of Earth’s circumference whose centre coincides with the center of the Earth (basically divides the earth into equal halves) o Small Circle = divides earth in unequal halves  Prime Meridian & Standard Time o Time changes every 15°per hr o International Date Line = where the day officially begins, from this line new days sweeps westwards o Time relies on tracking earth’s rotation, tug of tidal forces and re-arrangement of earth o Coordinated Universal Time (UTC) replaced Greenwich Mean Time (GMT) o Day light saving time = set 1 hr ahead in spring and set back 1 hr in fall Maps, Scales, and Projections  Map = generalized view of an area, usually some portion of earth’s surface, as seen from above and greatly reduced in size  Map Elements: Title, Legend, North Arrow, Scale, Date, Projection info  Types of Geographic Data: Discontinuous, Continuous, Qualitative, Quantitative  Cartography = part of geography that involves map making  Topographic Maps: high detail of surface area, physical and human feature, contour lines o Contour lines never cross, all points on the line have same elevation  Thematic Graphs o Point Symbol: dot density proportional symbols o Area Symbol: choropleth maps, cartograms o Line Symbol: quantitative or qualitative ‘  Cylindrical projections → Mercator projections, Planar projections → Gnomonic projection, conic projection → Albers equal-area conic projection, oval projections  Mercator present false size as toward poles areas smaller, Grthnland looks bigger than South America but in reality Green land only 1/8 size of south America o Contains rhumb line = denotes constant direction and appears as a straight line on the Mercator Remote Sensing = information acquired from distance, without physical contact with the subject  Active Remote Sensing = send out beam (ex. Satellite)  Passive Remote Sensing = Do it just by scanning environment with our eyes Geographic Information Systems (GIS) = computer-based, data processing tool for gathering, manipulating and analyzing geographic info  Combines different planes of data to create a new map (ex. Topographic base + Parcels + zoning + floodplains + wetlands + land cover + soil)  Photogrammetric = aerial photographs to improve accuracy of surface map Lecture  Invasive Species = can be native or exotic ex. Zebra mussels, Mute swans o Mute Swans – rapid growth of population & aggressive & eating food, attracted to urban areas because of heat and warmth, use egg addling control Readings th Chapter 2 – Solar Energy to Earth and the Seasons (Thursday May 19 ) The Solar System, Sun, and Earth  Solar system located on remote, trailing edge of the Milky Way Galaxy, a flattened, disk-shaped mass, Sagittaris A* is a black hole that sits in the middle  Solar system condensed from a large, slowly rotating and collapsing cloud of dust and gas called the nebula  Gravity = mutual attracting force exerted by the mass of an object upon all other objects (key force in this condensing solar nebula)  As nebular cloud organized and flattened into a disk shape, the early protosun grew in mass at the centre, drawing more matter to it  Small accretion eddies swirled at varying distances from the centre of the solar nebula; these were the protoplanets  Early protoplantes called planetesimals  Planetesimal Hypothesis, or dust-clouds hypothesis = how sun condense from nebular clouds with planetesimals forming in orbits about the central mass  Speed of Light = 300,000kmps or 7.5 times the equator in 1s or 186,000 mps or 9.5 trillion km per year (this distance called ‘light year’’)  Earth’s orbit around the sun is elliptical – closed oval path  Perihelion = position closet to sun during Northern Hemisphere winter (Jan 3)  Aphelion = position farthest away during Northern Hemisphere summer (July 4)  Earth rotates eastwards daily in its own axis Solar Energy: From Sun to Earth  Sun captured 99.9% of matter from nebula, 0.1% formed planets, debris, comets, etc  Typical of one of several 100billion stars  600K at surface  Enormous mass at high temperature and pressure →nuclear fusion (hydrogen particles collide to make helium and releases energy)  Takes 8 min 20s for sunlight to hit earth  Fusion = hydrogen atoms forced together causing the nuclei to join  Sun outputs: solar wind and radiant energy o Solar wind = clouds of charged gases emitted by the sun and traveling in all directions from the sun’s surface (effect on earth: auroras, disturbance in ratio signals, weather) o Solar wind takes 3 days to reach earth (8min for light) o Sunspots = caused by magnetic storms on the sun o Coronal Mass Ejection = charged material, contribute to flow of material in solar wind  Solar Wind Effects: o First interact with magnetosphere, deflects solar wind towards both of Earth’s poles (only small proportion enters) to create auroras o In 1969 used piece of foil to test for solar wind on moon o Interactions of solar win with upper layers of atmosphere produces auroras (at both poles) aurora borealis (northern lights) aurora australis (southern lights)  Electromagnetic Spectrum of Radiant Energy o Wavelength = distance between corresponding points on any two successive waves o Frequency = number of waves passing a fixed point in 1 second o Sun emits radiant energy: 8% ultraviolet/X-ray/gamma, 47% visible light, 45% infrared wavelengths o Physical law states that all objects radiate energy in wavelengths related to their individual surface temperatures: the hotter the object, the shorter the wavelength emitted o Blackbody radiator, emits much radiant energy as it absorbs, hotter the black body the more it radiates o Earth is cooler radiating body than sun so longer wavelengths are emitted (infrared portion only) o Solar spectrum is shortwave radiation that peaks in the short visible wavelengths, earth’s radiated energy is longwave radiation concentrated in infrared wavelengths  Thermopause = outer boundary of earth’s energy system and provides a useful point at which to assess the arriving solar radiation before it is diminished by scattering and absorption in passage through the atmosphere o Solar radiation that reaches a horizontal plane at earth is called insolation o Insolation at the top of the atmosphere is called solar constant = average insolation received at the thermopause o Subpolar point = only point receiving insolation perpendicular to the surface o Thermopause above the equatorial region receives 2.5 times more insolation annually than the thermopause above the poles Radiation = energy transmitted as waves of electric and magnetic oscillations  Sun radiates energy at the speed of light in a spectrum of wave lengths  Electromagnetic radiation is emitted by all matters with a temperature above 0K (-273°C)  Radiation intensity emitted depends on the temperature of the object: Stefan- Boltzman law (radiation intensity proportional to temperature^4)  Wavelengths of radiation is inversely related to surface temperature (hotter objects → shorter wavelengths)  Visible light is electromagnetic energy flowing from the sun at a certain wavelengths  Sun also emits infrared radiation, and ultra-violet radiation (and shorter wavelengths)  Earth emits long-wave radiation such as thermal infrared (heat)  Half radiation, sun emits shorter infrared, earth emits longer thermal infrared (heat)  Solar radiation o Insolation = solar radiation that hits the earth o Solar constant = average insolation received at the thermopause when Earth is at its average distance from the sun (1372w m-2) o Global Net Radiation = at higher latitudes, net radiation (from earth’s perspectives( is negative which means we are losing more energy to space than we gain from the sun o Lose more energy to spaces b/c higher altitude has ice/snow 1) reflects lots of angles 2) sun = less insolation Seasonality a product of the earth’s changing position in space, relative to the fixed position of our energy source (sun)  Refers to changing of day lengths and changes in the sun’s position above the horizon  The uneven receipt of insolation at the earth’s surface is what drives seasonality (b/c change in insolation over time and space)  5 Characteristics o Sphericity – insolation is latitude depended, due to the curvature of the Earth  ADD GRAPH  Look at how much more spread out the same amount of insolation is at higher (N/S) compared to the equator  More area covered near the poles compared to the equator in terms of same ray of sunlight o Revolutions – (earth’s orbit around sun, 365 days, add 1 day every 4 years )  Aphelion = earth farthest from sun (July 4)  Perihelion = earth closest to sun (Jan 4)  (above) seems counter intuitive b/c determination of temperature is by tilt & axial parallelism o Rotation = rotation around earth’s axis, 24 hrs  Equator length = day length 12hrs  Axis is angled at 23.5° from the plane of ecliptic  Axis always points to Polaris, no matter what time of the year ‘Axial Parallelism’ o Tilt = axis aligned at a 23.5° degree angle from a perpendicular to the plane of the ecliptic  Subsolar point = where sun energy hits earth directly  Declination = latitude of the subsolar point (within 23.5° of equator b/c earth tilted to that degree)  ** READ TEXT o Axial Parallelism – earth’s tilt is fixed on its revolution around the sun, which results in temporal variations  **READ TEXT  Winter = winter solstice, daylight switches from getting shorter to getting longer in NH  Spring = vernal equinox, 12 hours days and nights at all points on earth  Summer = summer solstice, switches from days getting longer to days getting shorter in NH  Fall = autumnal equinox, 12 hours days and nights at all points on earth Humidity & Calculations  **READ TEXT Chapter 4 – Atmosphere & Surface Energy Balances (Thursday May 19 )h Earth’s atmospheres  Uniform mixture of gases collectively referred to as air o Air pressure = the weight of the atmosphere o Division of Atmosphere by Temperatures (Troposphere → stratosphere → mesosphere → Thermosphere) o Main complements: Nitrogen (78%), Oxygen (21%), Argon (<1%), Carbon dioxide(<1%), Neon, Helium, Methane, Krypton, Ozone, Nitrous Oxide) o **READ TEXT 64-66, 71-73  Solar Radiation o Equatorial zones has many cloud formations actually not as hot as desert areas (clouds block short wave from entering) o Enters atmosphere:  Scattering (redirection of wavelengths) = gas molecules and dust redirected Short Waves radiation without altering wavelengths → diffuse radiation  Shorter wave lengths means greater scattering  Rayleigh Scattering → shorter wavelengths = greater scattering  Shorter wavelengths = blue (different angle of sun creates different colours)  Refracted = bending of Short Waves radiation due to change in density (after wavelengths)  mirage → radiation goes through different temperatures of air (hotter air then colder air)  Reflected = (31%) bounced back to space w/o being used  31% = 21% clouds + 3% ground + 7% atmosphere  Quantified as Albedo: % radiation reflected (outgoing radiation/ incoming raditation) o Snow: 80-95% reflected (light colour) o Forest: 10-20% reflected (dark colour) o Average planet = 31% “earth shine” o Higher albedo (snow, water) (light roof, asphalt) (earth, moon) (forest, grass)  K* = K↓(1-α) where α = K↑/K↓  Net Shortwave radiation (K*) = incoming radiation (K↓) multiplied by (1- albedo)  Absorption = (69%) converts short waves radiation into long waves radiation, or chemical energy by plants through photosynthesis  Absorption takes place in the atmosphere (24% if clouds, gases, dust, ozone) and on Earth’s surface o Clouds & Radiation  Cloud-albedo forcing  Clouds reflect insolation back to space  When clouds reflect short wave radiation upward = net cooling effect  Cloud-greenhouse forcing  Clouds insulate lower atmosphere by trapping long wave length radiation  When clouds trap long wave radiation downward = net insulating effect  Greenhouse Effect = outgoing long wave radiation is delayed in leaving the atmosphere (eventually radiated back to space from the surface and atmosphere) ~ keeps the earth’s energy in equilibrium over long run  Overall Energy Balance o In long run, incoming radiation = outgoing radiation o At shorter timescales, outgoing long wave radiation is trapped and re-radiated to the earth’s surface (Greenhouse effect) o Absorbed by clouds, gases, dust, results in a warming of o Net Radiation = +SW (insolation), -SW(reflected), +LW (infrared), -LW (infrared)  Net R = (SW↓-SW↑) + (LW↓-LW↑)  Note: (SW↓-SW↑) is surface albedo ● Lots of SW come in but few leave ●Small amount of LW come in but Large amount LW leave ● Top part (0-875W/m )2 is Sun → Earth ● Bot2om part (0- -525 W/m ) is Earth → Out  Heat Transfer at the Earth surface o About 45% of incoming solar radiation reaches the earth surface o Reaches earth:  1) Radiative transfers = loss to space and greenhouse effect  2) Non-Radiative transfers = heat transfer involving physical motion  Sensible heat (you can feel it): conduction and convection through material (ex. Ground heating, molecules all excited keep moving to get other excited)  Latent heat: “hidden heat”- energy absorbed form surroundings when the water evaporates, and stored in motion of vapour molecules (Ex. Sweat evaporates)  **READ TEXT o Highest global net radiation @ equator but dependent on oceanic circulation o Urban Areas & Energy Balance  Warmer around urban areas b/c lower albedo, geometric shapes, concentrated production of energy, air pollution Chapter 5 – Global Temperatures (Thursday May 19 )h Temperature  We feel sensible heat transfer (warmer or cooler)  Fahrenheit = archaic scale  Celsius = based on freezing point of water  Kelvin = used in science because it is an absolute measure of molecular motion, that is 0K is when there is zero motion  K → C (add 273)  Lag effect: long wave radiation reradiates from surfaces (diagram) o Similar to lag on annual cycle: shortest day in Dec, but coldest month in Jan, longest day in June, but July hottest month o Morning Coldest o Highest rays @ midway o But warmer couple hrs later b/c LW reflected  5 Determinant of local temperature: o Latitude:  Tropics – energy (angle of insolation is high, daylight is consistent)  Poles – energy (low sun angle, high reflectivity, long periods of zero insolation)  This energy imbalance drives global circulation in oceans and the atmosphere  Net radiative loss polewards of ~36° (  Consistent day length and high sun angle in tropics  Reflective surface, seasonality and low sun angle in polar regions  But ‘advection’ distributes heat polewards (atmospheric and ocean currents)  Higher latitudes more energy lost o Altitude (elevation)  as density of atmosphere ↓, fewer molecules available for sensible heat  that is why ice in tropics is possible  at higher elevations, larger diurnal temperature range as surfaces gain and lose energy rapidly with less dense air, which cannot effectively absorb outgoing long wave radiation  normal (avg) lapse rate = 6.4°C/1000m  higher elevation gain/lose energy east, particles (air particles farther apart) o Atmospheric Conditions  Clouds  Insulation at night results in raised min night time temps  LW re-emitted @ night  Cloud-albedo forcing during the day results in lower daily max temps  In coming insolation radiation can’t get in  Equatorial regions often cloudy so not hottest (vs. Desert) o Land-Water heating difference  Land heats and cools faster than water (water has higher heat capacity)  Large water bodies affect, create lake breeze in summer (cooler) o Surface Characteristics  Slope orientation: north vs. South  Topograhy  Urban Surfaces – dry compared to soil (not as much latent at loss)  Lower albedo -> warmer Lecture 3: Atmosphere & Ocean Circulations Air Pressure  Pressure is a force acting on a surface area (P= F/A) 2  Units: Newtons per m = Pascal (Pa) 100pa = 1 milibar (mb)  Air molecules move in different direction, size, amount which determines temp & density of air  Think of atmosphere as an ocean or air pressing down on earth’s surface  Measured through Aneroid barometer (uses pressure chambers), Mercury barometer (uses mercury and straw), weather balloons Pressure Gradient = the difference in pressure between two locations  Air flows from the areas of high pressure → areas of low pressure  Wind speed is directly proportional to the pressure gradient  Air pressure changes with altitude (diagram) o Air pressure decreases with altitude as air temperature and density decreases  Mapping pressure o banded isobars: to show gradual pressure change over large areas o closed cells of high & low pressures: develops more locally and have steeper gradients o (lecture 3, slide 11 for diagrams) Wind = horizontal motion of air across the Earth’s surface  Wind is lateral movement of air due to unequal heating of the earth’s atmosphere and hence differences in air pressure  Role of wind o Redistribute heat from the tropics to poles o Moves water vapour from ocean to land o Drives ocean currents o Creates waves  Pressure differences = unequal heating sets up pressure (density) difference that forces air from higher to lower density areas (diagram)  Measuring wind direction: wind vane  Measure wind speed: anemometer Driving Forces within the Atmosphere (determine wind speed & direction and overall circulation) 1. Gravity = downward force on the atmosphere 2. Pressure Gradient Force = high to low o Air flows from high pressure to low pressure to equalize o Steeper the temperature gradient, the steeper the pressure gradient, the stronger the wind (diagram) o Movement of air due to differences in pressure between 2 areas (diagram) 3. Coriolis Force = deflective force; affects wind direction o Air flow (high → low) is complicated by the rotation of the earth o Winds are deflected to the right in the Northern Hemisphere, to the left in the Southern Hemisphere due to the Earth’s rotation  The deflection occurs regardless of the direction the wind is moving o The faster the wind, the greater the deflection o **READ TEXT** 4. Friction Force = surface slowing o Above the earth’s surface (no friction) the Coriolis force and pressure gradient force produce geostrophic winds, which flow along an equal pressure path (diagram) o High pressure => fair, clear weather o Low pressure => stormy weather o **READ TEXT 152** Atmospheric Patterns of Motion  Primary high-pressure & low-pressure areas o Sitmulated by temperature:  Equatorial low-pressure trough  Polar high-pressure cells o Formed by dynamic factors:  Subropical high-pressure cells  Subpolar low-pressure cells o Note: ICTZ migrates with solar position (diagram) o Basically air move along equator to low pressure pushed up make clouds o General patterns of circulation in northern hemisphere (diagram next page)  Upper atmosph
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