GG101 Notes PDF

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The first half of the notes for the first Midterm. ...

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LESSON 1: Objectives: - Define and describe geography and physical geography - Review the subject matter of physical geography - Identify important geographic themes - Introduce systems theory What is geography? - The study of the distribution and characteristics of physical and human phenomena and the processes and relations that shape and organize those distributions - The key focus is on where are features distributed, what are their characteristics and how they are formed What is physical geography? - The spatial analysis of all the physical elements and process systems that make up the environment; energy, air, water, weather, climate, landforms, soil, animals, plants and microorganisms. Meteorology and climatology – study of weather and climate Hydrology – study of water Geomorphology – study of landforms and landscapes Pedology – study of soils Biogeography – study of the geography of organisms Empiricism: knowledge is gained through experience and careful observation Positivism: a rigorous scientific method is used whereby a hypothesis of some natural process is formulated and that hypothesis is tested by designing an appropriate field, lab, or mathematical experiment Geographic Themes 1. Spatial emphasis: location and place 2. Ecological View of Human Environment Relations: examine problems of natural resources, environmental degradation, pollution and similar topics 3. Regional Analyses: examine the characteristics of regions, the relations between regions, and how regions change through time and across space 4. Movement and Process: examines the processes that operate in systems and the movements of energy and material within them. These systems could be a natural phenomenon such as a tropical cyclone or river flow, or human activity or feature such as the flow of goods and services, or economic capital between locations System Theory System: a model of a portion of the natural or human landscape. There are boundaries that portrays it from the surrounding. There are usually flows of energy or matter between these components

Open system: where there may be transfers of matter and/or energy with the surroundings Closed system: is isolated and does not exchange matter and/or energy with its surroundings Positive feedback: if the change reinforces the original condition - If the feedback information encourages more change in the system - Stimulates further system changes - Example: global climate change o As melt points increase on ice sheets o Melt points are darker and reflect less sunlight due to lower albedo o Therefore, absorbs more solar energy which in turn melts more ice which forms more melt points Negative feedback: if the change acts to reduce the original condition - If the feedback information discourages continued change - Causes self-regulation in the natural system - Example: maintaining body weight o If body wright is too high you will decrease your inputs and make changes to stop the gaining of weight Equilibrium - Conditions are balanced or stable over time there is a steady state equilibrium o Water flowing in a stream channel o At certain velocity the flow is capable of moving a given amount for sediment on its bed o If the flow is constant, then the sediment transport will also remain unaltered - When condition in system are gradually changing over time it may appear that there is a steady state, but this short-term steady condition may be superimposed on a longerterm trend, this is a dynamic equilibrium - some systems may appear to be in a steady state or dynamic equilibrium and the system then experiences a major change when a threshold is crossed Atmosphere: a thin, gaseous veil surrounding earth, held in place above the planet by the force of gravity - formed by gases arising from within earth’s crust and interior and the exhalations of all life over time, the lover atmosphere is unique in the solar system - combination of nitrogen, oxygen, argon, carbon dioxide, water vapor, and trace gases Hydrosphere: earths waters exist in the atmosphere on the surface, and in the crust near the surface - Collectively, these waters form the hydrosphere - Frozen portion is the cryosphere - Water of the hydrosphere exists naturally in all three states Lithosphere: earth’s crust and a portion of the upper mantle directly below the crust form the lithosphere Biosphere: the intricate, interconnected web that links all organism with their physical environment is the biosphere

- The area in which physical and chemical factors form the contest of life LESSON 2 Objectives - describe the basic geometry of the Earth - review the properties of parallels and meridians - introduce the use of the latitude and longitude coordinate system describe standard times zones - examine the basic properties of map projections Shape of the Earth - not a true sphere - It is flattened at the poles and bulges in the equatorial zone Geodesy: the science that measures the shape of the earth and its magnetic field Geoid: the shape term that we apply to the earth Locating objects on the Earth - Take earth and slice it into two halves with a plane so that the plane passes through the center of the body. The line that is traced on the surface of the earth is called the great circle - Divide the earth in two unequal halves with a plane. The plane does not pass through the center. The line is called a small circle Meridian - A line that runs north-south on the globe connecting the poles - Follows a pathway along 180 degrees of arctic - They are one half of a great circle - A set of meridians are spaced farthest apart at the equator and converge at the poles - Any number of meridians may be drawn on a globe Parallels - A line that runs east-west and parallel to, or along, the equator - Run around the globe through 360 degrees of arc - They are entire small circles - They do not cross or converge at a given point - Intersect meridians at right angles - Any number of parallels may be drawn on a globe Latitude - Angular distance north or south of the equator measured from the center of the earth - Values vary from 0 degrees to 90 degrees north or south of the equator Longitude - Angular distance east or west of a fixed point or line called Prime Meridian measured from the center of the earth - prime meridian is a datum from which longitude is determined

- Values range from 0 degrees to 180 degrees east or west of the prime meridian SIX DIGIT NOTATION - Latitude and longitude of the location are given in degrees and then the degrees are subdivided into smaller divisions called minutes and seconds Latitudinal Zones (from north to south) 1. Artic: 66.5 degrees N to North Pole 2. Subarctic: 55 degrees N to 66.5 N 3. Midlatitude: 35 degrees N to 55 N 4. Subtropical: 23.5 degrees N to 35 N 5. Equatorial and tropical: 323.5 degrees N to 23.5 S 6. Subtropical: 23.5 degrees S to 35 S 7. Midlatitude: 35 degrees S to 55 S 8. Subantarctic: 55 degrees S to 66.5 S 9. Antarctic: 66.5 degrees S to South Pole Standard Time - sundial is a simple device - Sanford Fleming devised standard time zones - Greenwich Mean Time: the Prime meridian would function as the datum for standard time o The time zones were laid out in 15 degrees intervals of longitude centered on the prime meridian - The current international time system is called Coordinated Universal Time - Zulu is synonymous with UTC Map: generalized depiction of a portion of the earth surface and its features Cartography: the art and science of map making Topographic Map: depicts changes in surface relief (elevation) and shows natural and cultural features such as streams, wetlands, woodlands, developed areas, transportation routes and similar features Nautical Chart: shows details of shorelines and has information on water depths and shipping channels Thematic Map: illustrates the distribution of social or economic data Mental Map: use to move about and navigate through the spaces that are familiar to us Mapping Basics - Scaling maps - Graphic scale, representative fraction, written scale Graticule: a grid that functions as the coordinate system needed to locate objects Map Projection: process used to reduce the spherical earth to a flat surface - Important properties o Shape (conformal) o Area (Equal area, equivalence)

o Azimuth (true direction) o Equidistance (true distance) Four Common Classes of Projections - Cylindrical - Planar - Conic - Oval Goode’s Homolosine Projection: - An equal area map Robinson Projection - A compromise between equal area and true shape Miller Cylindrical Projection - A compromise map projection been equal area and true shape

LESSON 3 Objectives - describe the basics of remote sensing systems - examine a variety of imagery types - review the structure of a Geographic Information System - examine a GIS application Remote Sensing: obtaining information about an object through collection of data using an instrument not in physical contact with the object o weather and atmosphere o hydrology o vegetation o geology and geomorphology o global and environmental change o development o natural hazards, risks and disasters Types of Imagery 1. aerial photographs o vertical and oblique aerial photographs taken on a camera mounted on an aircraf o may be black white or colour, usually not in colour o films may be sensitive to visible light o relatively inexpensive o main disadvantage is that in their native format they cannot be processed digitally 2. digital images o most common are multi-spectral images and radar images o can be black white or colour o true colour, the colours on the image appear the same as they would to the human eye o false colour image is when the assignment of colours to the features on the landscape does not follow what would appear to our eye naturally 3. weather an atmosphere o satellite based sensors o measure thermal infrared radiation o imagery is updated frequently and permits tracking of weather systems 4. hydrology o 5. vegetation 6. geology 7. global and environmental change

8. development 9. natural hazards, risk and disasters Remote Sensing Systems - complete remote sensing system collects, processes, and analyzes data from the area of study Major Elements Include Energy Source: - the energy source is usually solar radiation - most important forms of solar radiation are visible light and infrared light - another important source of energy is radar - in most applications the radar is generated by a satellite antenna and directed towards the surface Propagation of Energy Through the Atmosphere: - energy must pass from the top of the atmosphere through the atmosphere to the surface - along that path the energy can be altered - example, as light moves through the atmosphere some is reflected and scattered back to space, while some is absorbed in the atmosphere and other passes through the atmosphere to the surface Energy Recorded at a Sensor: - when the radiation or radar reached the sensor, it is recorded, and a data set is generated o sensor types: camera, fil, video recorders, television cameras, multi-spectral scanners - data is stored and transmitted back to a ground station Analyses and Interpretation of Data; Generation of Product: - data collected requires extensive processing to remove some of the atmospheric effects, correct for geometry and to enhance the images - analyses may be sued to find patterns in the data and classify images - aerial photography and radar images can also be used to build elevation models of the surface - a range of products can be generated for a user Active and Passive Sensing Systems: o Active Remote Sensing  Energy is generated by the system itself and is directed at a surface and the reflected or emitted response is measured and recorded (e.g., radar). o Passive Remote Sensing  The system measures and records energy that is emitted from a surface or solar radiation that is reflected from a surface. Visible light and infrared light from the Sun that are reflected from a surface are examples of passive remote sensing Geographic Information Systems (GIS)

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The mountain of data collected by remote sensing can be put to work in GIS Computers process geographic information from direct surveys and remote sensing in complex ways never before possible GIS methodology is an important tool for better understanding earth’s system and is a vital career opportunity for geographers o Three elements  Database management  Spatial data analyses  Computer based cartography o Several tasks  Mapping and surveying  Analysing distributions  Examining spatial relations between variables

LESSON 4 Objectives - define energy and radiation and review their properties - review the characteristics of solar and terrestrial radiation - introduce the concept of a radiation balance - examine the orbital relations between the Earth and Sun Energy: A measure of the ability or capacity of a system to do work. - Work is done when matter is moved over some distance - Energy cannot be created or destroyed - The form of energy can change - Energy can be transferred from one location to another Radiant energy - The emission and propagation of energy through space or a material medium in the form of waves - For the earth, the most important source of radiant energy is the Sun - It drives the climate and hydrological systems that operate in the atmosphere and on the surface Solar output - Sun functions as a fusion reactor in which hydrogen atoms fuse into helium atoms and large quantities of energy are liberated - Temp of the surface of the Sun: 6000 K - The sun emits radiant energy and also the solar wind Solar wind - Consist of clouds of charged particles, mainly protons and electrons, that stream outward from the outer layers of the Sun - Solar wind :400km/s but the density of the solar wind - Plays an important role in generating the auroras of the polar regions - Can also disrupt telecommunications and has some possible links to weather phenomena int eh earths atmosphere Electromagnetic radiation - Energy that propagates through space or through a material medium in the form of an advancing disturbance in electric and magnetic fields Waves - Described through wavelengths and frequency - Wavelength: the distance between the crest of one wave and the adjacent wave - Frequency: the number of waves or cycles that pass a point per unit of time-Hertz - Long wavelengths have low frequencies and short wavelengths have high frequencies Electromagnetic Spectrum - Most important portions are the: ultraviolet, visible light, infrared light - Visible light is the electromagnetic radiation that the human eye can sense, that light is in turn broken down into different wavebands

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The infrared part of the spectrum is also divided into different bands: near, shortwave, middle and thermal

Radiation Properties - All objects with a temperature above absolute zero (0 K = -273.15°C) emit radiation - The higher an object's temperature, the greater the amount of radiation emitted per unit of surface area (Stefan-Boltzmann Law) - The higher an objects' temperature, the shorter the wavelength of maximum radiant emission (Wien's Displacement Law). - Objects that are good emitters of radiation (at given wavelengths) are also good absorbers (of those same wavelengths). - A blackbody is a perfect absorber and emitter. Shortwave Radiation - Solar (Sun) radiation: emissions are dominated by ultraviolet, visible and near to middle infrared wavelengths Longwave Radiation - Terrestrial (Earth) radiation: emissions are dominated by thermal infrared wavelengths - Sun behaves as a blackbody with respect to shortwave radiation as does the earth’s surface for longwave radiation - However, the earth’s atmosphere does not behave like a blackbody o It selectively absorbs and emits different wavelengths in the thermal infrared Net Radiation: the difference between the incoming radiation and the outgoing radiation from the system - For the earth as a whole the balance terms are: o Incoming shortwave radiation  denoted by the symbol SW↓ (SW down), this in the incoming solar radiation (insolation) o Outgoing longwave radiation

denoted by the symbol SW↑ (SW up), this is the incoming solar radiation that is reflected or scattered back to space by atmospheric components (such as clouds and aerosols) or the Earth's surface o Outgoing longwave radiation  denoted by the symbol LW↑ (LW up), this is the longwave radiation that is emitted by the Earth's surface or the atmosphere that goes to space o Incoming Longwave Radiation  denoted by the symbol LW↓ (LW down), this is the longwave radiation that is emitted from the atmosphere back to the Earth's surface 

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earth has a positive net radiation in the equatorial and tropical regions negative net radiation in the midlatitudes, sub-polar and polar latitudes the planet gains energy in the low latitudes and loses energy in the high latitudes

Earth-Sun Relations - earth’s orbit around the sun does not follow a perfectly circular path, as its an ellipse - earth is closest to the Sun in early January – called perihelion - the furthest from the sun in early July – called aphelion - the earth receives slightly different amounts of solar radiation through the course of the year - the ellipse changes its shape over long periods of time - joining all points on earth’s orbit to produce a plane-the surface is called the plane of the ecliptic - earth’s axis is tilted, earth rotates on its polar axis o the axial tilt is 23.5 degrees but that also changes over long periods of time - note that the earth’s axis remains tilted at the same angle through the course of the year, this phenomena is called axil parallelism Why Do We Have Seasons? - Five factors o Revolution o Rotation o Axial tilt o Axial parallelism o Sphericity

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Although true seasonal variations are due to only two variables o Axial tilt o Axial parallelism Because of the fixed tilt of the axis, the northern and southern hemispheres receive markedly different amounts of solar radiation on a seasonal basis This in turn influences the seasonal temperature changes

LESSON 5 Objectives - describe the composition of the atmosphere - examine the vertical structure of the atmosphere in terms of temperature - review the function of some atmospheric components Composition - mixture of gases and suspended liquids and solids - gaseous components are divided into non variable and variable gases o non-variable gasses: relatively stable in the atmosphere over long periods o variable gases: experience fluctuations in their temporal and spatial distribution over relatively short periods

Non-variable gases Nitrogen: - most abundant in the atmosphere by volume - exists in the compound N2, where two nitrogen atoms are tightly held by a triple covalent bond - very stable gas - enters chemical reactions only when abundant energy is supplied - natural example: within the air column that immediately surrounds a lightning strike - can also be removed from the atmosphere to produce ammonia compounds by nitrogen fixing bacteria that live in the soil zone or are associated with root structures of certain plants Oxygen: - essential for organism that use it in the process for respiration - all of the oxygen present is due to the biological process of photosynthesis whereby CO2 is converted into O2 - exists primarily as O2 but also occurs as O3 - highly reactive gas and readily forms oxides with a variety of mineral compounds in the presence of water Noble Gases - include argon, neon, and helium - very stable and do not enter chemical reactions Variable Gases Carbon Dioxide - gas that is essential to photosynthesis - an association between global temperatures and atmospheric carbon dioxide concentrations, as carbon dioxide is an important greenhouse gas - In almost 175 years the concentrations of CO2 have increased from approximately 280 ppm o Attributed to anthropogenic sources with fossil fuel combustion Water Vapour - Concentration is highly variable-around 1.4% - Warm air has a greater capacity of water vapour than cold air - On avg the water vapor content of the atmosphere is higher where temperatures are high - ...