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Midterm

GG101 Midterm review.docx

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Department
Geography
Course
GG101
Professor
Bruce Mc Kay
Semester
Winter

Description
GG101 Intro Geography:  Is the science that studies the relationships among, natural systems, geographic areas, society, cultural activities and the interdependent of all of these space  Geography from geo “earth”and graphin “to write”  Geography is o A method, not a body of knowledge o Use spatial analysis  Geography is divided into two major branches o Cultural geography (human geo) o Physical geography (natural geography)  Physical Geography o The spatial analysis of all the physical elements and processes that make up the earths  Hydrosphere  Composed of all of the water on or near the earth  Biosphere  Earths living ecosystems  Atmosphere  Body of air which surrounds our planets  Lithosphere  Is the solid rocky crust covering entire planets  Geographic Themes o Spatial emphasis  Location and place, where features are and wear their unique characteristics  Earth system concepts o System: is model or a representation of a portion of the natural or human landscape o Closed systems: is isolated and does not exchange matter and or energy with is surroundings, rare in nature o Open systems: includes the flow of both energy and matter. All environmental systems are open systems Lecture 4 1) Energy a. A measure of the ability of a system to do work b. Note that Work is done when matter is moved over some distance c. Energy cannot be created or destroyed, but the form of energy can change. Energy can be transferred from one location to another i. Examples include kinetic or potential energy d. Kinetic energy: is associated with motion. It is the type of energy that a moving automobile or thrown baseball is. e. Potential energy: is they type of energy possessed by an object because of its location or configuration and is essentially a relative quantity 2) Radiant energy a. The energy of electromagnetic waves (Radiation) 3) Solar output a. Solar Wind i. Clouds of charges (ionized) gases emitted from the suns surface. Responsible for auroras, communications disruption, possible weather links 4) Electromagnetic Radiation a. Energy that propagates through space or through a material medium in the form of an advancing disturbance in electric and magnetic fields Questions 1) What is the relation between wavelength and frequency? a. They are inversely proportional if you increase the distance between the troughs and peaks. You will decrease the frequency with which each trough or peak passes a fixed point 2) What are the wavelengths of the common forms of radiation a. Different wavelengths of electromagnetic radiation cause different types of effects on people b. UV rays i. it is radiation that is similar to visible light in all physical aspects , except that it does not enable us to see things. Uv rays have shorter wavelengths (higher frequencies) compared to visible light but have longer wavelengths (lower frequencies) compared to X-rays c. Infrared with wavelengths longer than the color red, is invisible to the humane eye. Infrared falls between microwaves and visible light waves because its waves are shorter than microwaves but longer than those of visible light. Most of the energy from the sun that arrives is infrared radiation. d. Visible Light spectrum is the portion of the ray spectrum that can be detected by the light. We see these waves as the seven colors of the rainbow. Each color responds to a different wavelength of the electromagnetic spectrum Radiation principles 1) Key points a. All objects with a temperature above absolute zero emit radiation excluding dark matter b. The higher an objects temperature the greater amount of radiation emitted per unit of surface areas c. The higher an objects temperature the shorter is the wavelength of aximuum radiant emission i. Wien Displacement Law 1. The warmer the object, the shorter the wavelength emitted by that object d. Objects that are good emitters of radiation ( at given wavelengths) are also good absorbers (of those wavelengths) e. A blackbody is a perfect absorber and emitter i. A blackbody is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence.. it holds a constant, uniform temperature. ii. Blackbody radiation refers to an object or system which absorbs all radiation incident upon it and re radiates energy which is characteristic of this radiating system only. Not dependent upon the type of radiation which it is incident upon it iii. Easy version 1. It is a theoretical object that absorbs 100 percent of the radiation that hits it. Therefore it reflects no radiation and appears perfectly black. iv. Easiest version 1. A object capable of absorbing all the electromagnetic radiation falling on it. f. Terms i. Because of its high temperature the sun emits more radiation, per unit surface area and shorter wavelengths. the output is dominated by wavelengths in the ultraviolet, visible and near infrared portions of electromagnetic spectrum. ii. The earth on the other hand emits only 300 k of surface temperature and thus the earth emits far less radiation than the sun and also emits longer wavelengths. Earths radiative output is dominated by wavelengths in the thermal infrared portions of the electromagnetic spectrum. Collectively we refer to this as longwave Radiation. for this reason the earths atmosphere does not radiate like a blackbody to space. Note  The sun is a blackbody because although it takes in energy and light it does not reflect it. It uses that light/energy to make its own light/energy.  The earth’s surface is a blackbody because it does not reflect any light or energy. It also is capable of absorbing all the electromagnetic radiation falling on it. The earths atmosphere however is not one since it has selective absorption What is responsible for the absorption of longwave radiation in the atmosphere?  Greenhouse effect does it Greenhouse Effect and atmospheric warning  Atmosphere absorbs heat energy  A real greenhouse traps heat inside  Atmosphere delays transfer of heat from earth into space  High clouds=net greenhouse forcing and atmospheric warning  Low clouds: net albedo forcing and atmospheric cooling 4) Net radiation (Q*)  Net radiation is the balance between incoming and outgoing radiation  Q*= Incoming-Outgoing  Incoming suns radiation is not evenly distributed on the earth  Shortwave vlues are greatest in the equatorial regions and lowest in the polar regions with much more variation in the polar regions Terms  Short wave radiation contains a lot of energy, long wave radiation contains less energy than shortwave radiation.  Solar energy enters our atmosphere as shortwave radiation in the  Earth absorbs the solar energy through its atmosphere and gases and re- radiates energy as longwave radiation  Earth emits longwave radiation because earth is cooler than the sun and has less energy available to give off. 5) Earth Sun Relations key points Earth has an elliptical Orbit about the sun  At perihelion (Jan 3, Earth to Sun distance is 1.47 x 10^8km)  At Aphelion (Jul 4, eath to sun distance is 1.52 x 10^8 km) The amount of sunlight the earth receives is called insolation: incoming solar radiation  Two factors cause insolation to change o Length of day (because more hours of daylight mean more insolation o The angle ha sunlight strikes the earths surface o When the sun shines directly overhead it is more concentrated in a smaller area therefore stronger compared to the evening when the sun is lower in the sky the sunlight is less intense because it gets spread out over a larger area. Change in seasons  As the earth revolves around the sun its axis is tiled slightly. On the summer solstice earths north of the equator experience longer days and shorter nights  And on the winter solstice the tp of the earths axis is pointed directly away from the sun  Halfway in between the summer and winter solstices are the equinoxes. At theses times the earths axis is pointing neither toward nor away from the sun. these days have exactly12 hours of daylight and 12 hours of night  So in summary the tilt of earths axis gives us the seasons. We experience seasons because the earth rotates on an axis that titled in its orbit that causes the different hemispheres to be at different angles to the sun at different times of the year..  Is titled 23.5 degrees from the vertical Annual Mark of seasons  Winter Solstice- December 21 st o Subsolar point Tropic of Capricorn  Spring equinox-march 20 o Subsolar Point Equator  Summer Solstice-June 20 o Subsolar Point Tropic of Cancer  Fall equinox- September 22 o Subsolar point Equator Reasons for seasons  Revolution  Rotation  Tilt of earths axis  Axial parallelism  Sphericity Lecture 5 Atmospheres  The Atmosphere is the gaseous envelope that surrounds the earth; it is a mixture of gases and suspended liquid and solids.  Aerosols are liquids and solids (but not water or ice) that are suspended in the atmosphere. 1) Composition a. Some of the gaseous components have accumulated from biological processes. The early atmosphere had constituents such as methane, carbon dioxide. The modern atmosphere s different there are categorized by variable and non variable gases i. For the non-variable gases the concentrations are relatively stable over time and space ii. The variable gases are those that can experience relatively large changes in their concentration either over time or across space. b. Non-variable gases i. Nitrogen 1. Very stable gas 2. Enters into reactions only when abundant energy is supplied ii. Oxygen 1. Exists primarily as O2 but also ovvurs as O3 in very low concentrations iii. Variable Gases 1. These gases constitute a small percentage of the total volume and mass of the atmosphere, but they can experience spatial and temporal variations in their concentration a. Carbon Dioxide i. Gas is essential to photosynthesis ii. It is the mobile carbon in the earth atmospheric system iii. Concentration fluctuate naturally (Carbon dioxide is more soluble in cold water, atmospheric concentration tend to be lower during periods od continental glaciation) iv. One of the key greenhouse gases b. Water Vapor (H2O) i. Concentration in the atmosphere are highly variable (-01-4.0) and are higher in lower atmosphere ii. Water vapor has a short residence time in the atmosphere. It is rapidly cycled from the oceans and land to the atmosphere iii. Another important greenhouse gas c. Ozone (O3) i. Present in the stratosphere where it is produced from a photochemical reaction with ultraviolet radiation ii. Stratospheric ozone is broken down by synthetic refrigerants such as cfcs iii. Also present near round level where it is a component of photochemical smog d. Methane i. Produced from anaerobic decomposition and human industrial activities ii. Occurs in low concentration but has experienced a doubling in the alst 150 years e. Aerosols i. Liquids and solids that are temporarily suspended in the atmosphere ii. Included natural sources such as volcanic ash, dust, soot, sea salts, spores etc iii. Industrial activities also contribute particular matter iv. Influence the energy balance of the earth by increasing scatter back to space f. Vertical Structure i. From the base of the troposphere to the top of the atmosphere there is a reduction In density and atmospheric pressure. Density is mass per unit volume, and pressure is a force applied per unit area 1. Density= Mass/Volume 2. Pressure=Force/Area 3. Force= Mass Acceleration (mg)=weight ii. The atmospheric pressure at any point in the atmosphere is simply the weight of an overlying atmosphere iii. Based on temperature the atmosphere is divided into: 1. Troposphere 2. Stratosphere 3. Mesosphere 4. thermosphere 2. Four Types of Temperature i. Troposphere 1. 80% of the mass of the atmosphere 2. A turbulent well mixed layer 3. Has large and rapid transfers of water vapor 4. On average temperature decreases upward at 6.4 Celsius Tropopause: boundary zone  Temperatures are steady  Altitude varies with latitude and season, it is highest in the tropics ii. Stratosphere 1. Temperature increases with altitude 2. Concentrations of ozone as are highest in the stratosphere, the absorption of UV radiation by ozone generates heat 3. It is difficult for air to rise into and through the stratosphere because of the inverse although there is some circulation of air between the troposphere and stratosphere a. Stratpaus-boudnary zone 50km altitude iii. Mesosphere 1. Temperature profile shows a decline with altitude a. Mesopause-boundary zone approx. 80 km altitude 3. Function a. The atmosphere (above the troposphere) may be subdivided into the ionosphere and ozonesphere. The ionosphere (mesosphere and thermosphere) absorbs Gamma and X-ray radiation. The ozonosphere (Stratosphere) absorbs UV radiations. These functions are essential to the sustaining of life on the surface of the earth 4. Atmospheric Issues a. Acid deposition i. Commonly known as acid rain, occurs when emissions from the combustion of fossil fuels and other industrial processes undergo complex chemical reactions in the atmosphere and fall to the earth as either wet rain or dry gases ii. The main chemical precursors leading to acidic conditions are atmospheric conc
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