Introduction to Physical Geography - Test One Notes | GEOG 1111, Study notes of Geography

Download Introduction to Physical Geography - Test One Notes | GEOG 1111 and more Study notes Geography in PDF only on Docsity! UGA 11 1 File Title Read 1-23 and 40-54 Introduction I. Earth Systems Concepts a. Systems theory b. Open Systems c. Closed systems d. System feedback e. System equilibrium f. We hear it a lot i. Weather systems 1. Hurricanes 2. Mid-latitude cyclones ii. AC iii. Plumbing iv. River II. Systems a. Set of interrelated components that exchange things i. Physical systems: exchange energy and matter b. Energy: the ability to accomplish work c. Matter: stuff, substances made up of molecules and atoms III. Open system a. Most natural systems not self contained b. Inputs of energy and matter flow into and out of the system c. Earth is an open system in terms of energy i. Solar energy enters and heat energy leaves d. Things came come in and go out the other side IV. Closed system a. Shut off from surroundings b. Earth is a closed system for physical matter c. Everything is self contained V. Equilibrium: inputs = outputs a. Not in eq = climate change – more energy going into the system than coming out – no longer in eq – temps change over time b. Natural systems try to maintain it VI. Feedback: outcome of an event acts to influence the system (the output “feeds back as an input”) a. Positive feedback: outcome reinforces the process, spirals it up, promotes change, DESTABILIZING i. Water is good at absorbing energy (heat trapping gas) – water vapor means more energy is trapped in like a blanket – that means its warmer – that makes it warmer b. Negative feedback: outcome cancels out the process, resists change, STABILIZING i. Water vapor feedback – warmer = holds more water vapor – means more clouds and that leads to increased albedo because of reflection – if it UGA 11 2 File Title reflects more sunlight it doesn’t get to the surface – less energy to the sun leads to cooling VII. Four spheres to model the earth system a. Atmosphere b. Hydrosphere c. Lithosphere d. Biosphere VIII. Location and time on earth a. Latitude – horizontal i. Slightly fatter going horizontally than vertically – bulges at the equator – 26 miles wider at the equator ii. Position north or south of equator iii. Ranges 0 degrees at the equator to 90 degress north or S at the North or South Pole iv. Other important latitudes 1. Equator at 0 2. Tropic of Cancer 23 ½ degrees N 3. Arctic Circle 66 ½ degrees N 4. Tropic of Capricorn 23 ½ S 5. Antarctic Circle 66 ½ degrees S b. Longitude – vertical i. Position east or west of Prime Meridian ii. Ranges 0 to 180 degrees east or west iii. Prime Meridian is an arbitrary reference point (o degrees longitude) – Greenwich, England iv. International Date Line is 180 degrees c. Prime Meridian and standard time IX. GPS systems a. Identify your latitude, longitude and elevation Earth/Sun Relationships I. Milky Way Galaxy II. Sun a. Major sources of earth’s energy b. Fusion of hydrogen atoms in the core c. Earth-sun relationships affect amount of energy received d. Consider the temperature range in Athens i. 80 in July and 40 in January – the difference would be smaller closer to the equator III. Earth/ Sun relationships a. What does the earth do i. Rotates on its axis 1. Causes daily (diurnal) rhythms 2. Affects winds and ocean currents a. Coriolis force 3. Affects tides of large water bodies UGA 11 5 File Title 1. In upper atmosphere (stratosphere) – O3 2. Absorbs lethal UV radiation from the sun 3. Ozone hole 4. Pollutant at the surface 5. CFCs break up ozone --> hole 6. Depletion consequences a. Increased skin cancer b. Increased cataracts c. Increased immune system problems d. Crop reduction, effects on biosphere 7. Hole Remedies a. Montreal Protocol (1987) – international agreement to slow/stop release of CFCs b. CFC production has virtually ceased sinces early 1990s c. But it will take 50-100 years to reverse ozone depletion, because chlorine molecules are very stable 8. Aerosols a. Small solid particles and liquid droplets b. From human and natural processes c. Reduces visibility d. Helps in cloud formation – surface for water to latch onto – pm causes health problems – fed government establishing thresholds v. Particles vi. CFCs c. Anthropogenic Pollution i. Human caused air pollution ii. Mainly from combustion of fossil fuels 1. Carbon monoxide 2. Nitrogen oxides 3. VOCs – volatile organic compounds iii. Photochemical smog 1. Pollutant gases (nitrogen oxide and VOCs) + sunlight a. Ozone – human health danger b. PAN – bad for plants II. Vertical Structure of the Atmosphere a. Define these levels based on changes in temperatures b. Lapse rate – change in temperature with height – when it increases termperature with height its an inversion c. In between each layer we have transition zones – tropopause, stratopause, mesopause d. Troposphere i. Most of life on the planet exists and our weather takes place ii. Temperatures decrease with height e. Stratosphere i. Temps increase with height – inversion ii. Concentration of ozone – ozone layer – forms here because there is aperfect balance between solar energy and air that provides the source UGA 11 6 File Title f. Mesosphere i. Temps decrease with height g. Thermosphere i. Temps increase with height h. Temperature inversion – inversion under the surface leads to concentration III. Atmospheric Pressure a. Pressure: force exterted by the atmosphere on a certain area b. At sea level approx 15 lbs/in c. Density and atmospheric pressure – density = mass/volume Energy in the Earth-Atmosphere System I. Energy a. Energy is the ability to do work on some type of matter b. Work is done on matter when it is pushed, pulled, or lifted II. Energy Transfer Mechanisms a. Conduction i. Molecule to molecule transfers of energy 1. Most important near the surface (ground) b. Convection i. Convection: rising and sinking air (ie vertical motions) ii. Advection: horizontally moving air (wind) iii. Can transfer two types of energy 1. Sensible heat – heat that you can feel 2. Latent heat – hidden iv. Transfers by mass movement of some fluid v. Important with fluids c. Radiation i. Everything emits radiation ii. Doesn’t need some medium to move 1. Can travel through space iii. Consists of electromagnetic waves iv. Different because it doesn’t need something to flow through v. Describe radiation by wavelength – distance between two peaks – defines the type of radiation it is 1. Long waves or short wavelengths with short distances vi. Wavelengths are small 1. Length described using micro meter a. One millionth of a meter 2. Visible light = .5 mm 3. Letter in textbook = 2000 mm vii. The amount and peak intensity may differ III. The Electromagnetic Spectrum a. Gamma Rays (shorter) b. X Rays c. Ultra Violet d. Visible e. Infrared UGA 11 7 File Title f. Thermal Infrared g. Microwave h. Radio (longer) IV. We’re focusing on a. Ultraviolet b. Visible c. Near Infrared d. Thermal Infrared V. Radiation Laws a. Stefan-Boltzmann law – the hotter an object, the more radiation it emits b. Wein’s Law – the hotter an object, the shorter the wavelength of maximum intensity VI. Intensity and Wavelength Emitted – Earth and Sun a. Solar (shortwave) radiation i. Incoming solar radiation or insolation ii. There are minor variations in solar output iii. Sunspots 1. Greater number of sunspots = brighter sun 2. Solar variation ~.1% 3. Cycle ~11 years iv. Solar constant 1. The average amount of insolation at the top of the atmosphere at the mean Earth-Sun distance 2. Its about 1372 W m squared b. Atmospheric Influences on insolation i. As solar radiation passes through the atmosphere, things happen to it (ART) 1. Absorbed 2. Reflected or Scattered 3. Transmitted ii. These affect radiation received at the surface c. Absorption i. The assimilation of radiation by molecules of matter and its conversion from one form of energy to another ii. The temperature of the absorbing surface increases d. Scattering i. The process where small particles deflect radiation into different directions ii. Gives us blue skies 1. Scattering by air molecules (Rayleigh) iii. Scattering by dust and haze (Mie) e. Reflection and Albedo i. Turns it back the way it was coming from – higher albedo means a more reflective surface ii. Earth’s (average) albedo is 31% - 31% of the energy coming from the sun gets reflected away and can’t do any work f. Clouds and Forcing i. Reflect incoming shortwave radiation – cooling effect UGA 11 10 File Title V. Annual Temperature Cycle VI. Principal Temperature Controls a. Latitude i. Lower latitude = small range of temperatures with higher temps ii. Higher lat = larger range of temperatures with colder temperatures iii. Averaged over the course of the year – the avg temp near the equator is higher because there is more energy available iv. Decreases as you move toward the poles b. Altitude i. Higher altitude = lower temperatures ii. More vegetation in the lower altitude areas iii. Lapse rate – change in temperature with height c. Cloud Cover i. Large-scale circulation patterns can influence cloud cover and thus temperature 1. Eg the Asian Monsoon ii. Clouds and Radiation 1. They reflect away sunlight – reduces the max temp because it prevents sunlight from reaching the surface 2. They also are selective absorbers and absorb longwave radiation – at night cloudly conditions make it warmer – reemits it to the surface 3. Daily Temp Range – clear vs cloudy d. Land and Water i. Land tends to heat up and cool down more quickly than water 1. Less evaporation – lower latent heat – less water – energy goes into making it hot instead of evaporating water 2. Surface is opaque – energy gets absorbed by the ground and concentrated heat 3. Land has a lower specific heat – how much energy it takes to raise the temp of an object 4. Land has no mixing between layers ii. Water conditions are more moderate – water warms and cools slowly 1. Greater evaporation – higher latent heat 2. Surface is transparent 3. Higher specific heat – takes more energy to raise its temperature – gets distributed over a larger area 4. Water has mobility and mixes in vast ocean currents – distributes the warmer water with the cooler water iii. San Francisco vs Wichita Water and Atmospheric Humidity 1) Ocean and Freshwater Distribution a) All water – 97.22 % in the oceans – salt water i) Fresh = 2.78% - most is locked in ice sheets and glaciers - climate change we’re worried about them melting that feeds into sea level rise ii) Atmosphere is important for weather and climate - .03% UGA 11 11 File Title 2) Hydrologic Cycle a) Movement of water winting and between earth and the atmosphere b) We’ll focus on the vapor state 3) Atmospheric Humdity a) Humdiity – a generic term for the amount of water vapor (water in a gas phase) present in the air b) Humidity Measures i) Absolute Humidity (1) Mass of water vapor in air (g)/ volume of air (m3) (2) Vapor density (3) Meterologics don’t like to use this – humidity value can change – works for scientists near the ground ii) Specific Humidity (1) Mass of water vapor in air (g) / total mass of air (kg) iii) Mixing Ratio (1) Mass of water vapor in air (g) / mass of dry air (kg) 4) Dew Point Temperature a) Dew point temperature – the temperature to which the air must be cooled (with no change in pressure or moisture content) for saturation of the air to occur b) Works like termpature – if its high there is a lot of moisture in the air – over 65 F is humid and uncomfortable 5) Vapor Pressure a) The amount of atmospheric pressure exerted by water vapor molecules 6) Saturation a) The maximum amount of water that can exist in the atmosphere as a vapor at a given temperature i) Occurs when evaporation = condensation b) We can look at saturation values for each of the measures of atmospheric humidity i) Saturation Vapor Pressure (1) The higher the temperature, the higher the saturation value (2) Its not linear – bigger changes at higher temperatures – as it gets hotter the capacity for moisture increases (a) Hotter the air, the more capacity it has for water vapor (3) If air has a lot of energy it has a lot of energy to keep water in the gas state ii) Saturation Specific Humidity iii) Saturation Mixing Ratio c) To get clouds or fog or dew, the air needs to be brought to saturation – this can be done by: i) Adding moisture ii) Mixing cold air with warm air (1) See your breath on a cold day iii) Lowering the temperature (1) Most important for cloud formation 7) Relative Humidity a) RH = actual amount / capacity i) Find capacity using a graph b) RH = (SH/SSH)*100% - spec humidity/ saturation spec humidity OR vapor pressure/ saturation vapor pressure UGA 11 12 File Title c) Ratio of how much actual moisture there is to how much there is at a maximum d) It DOES NOT uniquely determine the amount of water vapor i) Analogy – fuel gauge in a car – tells you how close you are to being full/ at the saturation point e) Can be useful for showing how close to saturation f) Thisnumber can change if i) You add moisture to the air – increases the number ii) Increases if the air temperature changes/goes down 8) Humidity Instruments a) Hair Hygrometer i) Bundled strands of human hair are held tightly between two brackets – mechanism to sense tension form hair strands ii) Rotating drum and graph paper on which relative humidity readings are traced b) Sling Psychrometer i) Two thermometers – wick on the end dipped in water ii) When swung, water evaporates from the wick, cooling the wet-bulb thermometer – dryer air results in lower temperature Stability and Lifting Mechanisms 1) Atmospheric Processes a) Processes like fog, clouds, and precripitation involve getting the air to saturation b) This can be done by adding moisture or by cooling the air to lower the capacity i) Diabatic (1) Energy is added or removed from a system (2) Examples (a) Boiling water (b) Air that passes over a warm (cold) surface gains (loses) energy (3) Important for fog but not clouds (4) Any situation where temperature would change without the addition or subtraction of energy – has to do with pressure – tire compression example ii) Adiabatic (1) Processes in which temperature changes but no heat is added or removed from the substance – doesn’t take away energy (2) Most important process for cloud formation (3) First Law of Thermodynamics (a) Heating = work done + change in internal energy (i) When you add energy to something you heat it, could go into work or changing temperature (ii) Work done (expansion or contraction) (iii) Change in internal energy (temperature change) (b) In Adiabatic heating = 0 (because there is no heat added or removed) (i) 0 = work done + change in internal energy (ii) –work done = change in internal energy (iii) If you do work, if something expands, that leads to a decrease in temperature – contraction leads to an increase in internal energy 2) Lapse Rates a) Change in temperature/ change in height