AOSC123 EXAM 1 STUDY GUIDE
AOSC123 EXAM 1 STUDY GUIDE AOSC123
Popular in Causes and Implications of Global Change
Test Prep (MCAT, SAT...)
verified elite notetaker
Popular in General Science
This 12 page Study Guide was uploaded by Trang Le on Monday March 7, 2016. The Study Guide belongs to AOSC123 at University of Maryland taught by Rachel Pinker in Winter 2016. Since its upload, it has received 127 views. For similar materials see Causes and Implications of Global Change in General Science at University of Maryland.
Reviews for AOSC123 EXAM 1 STUDY GUIDE
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 03/07/16
AOSC123 EXAM 1 STUDY GUIDE Composition of the atmosphere: Nitrogen (about 78%), Oxygen (about 21%), Argon (about 0.93%), trace gases and CO2 (0.039%). 4 layers of the atmosphere: (1) Troposphere [12km], (2) Stratosphere [45km], (3) Mesosphere [85km], (4) Thermosphere [>300 km]. How temperature is measured: It’s done at 2m level in a protected and ventilated screen. Temperature is often lower with increasing altitude. Radiosonde: think a balloon! This measures temperature, humidity and wind above the earth surface. Ionosphere: it is ionized by solar radiation. It plays an important part in atmospheric electricity. It has practical importance because, among other functions, it influences radio propagation to distant places on the Earth. Weather: the exact state of the atmosphere at a point in time. Climate: statistics of atmosphere over a period of time, usually several decades or longer. Latitude: measure of position in North-South direction Longitude: measure of position in West-East direction Solar Activity: solar flares (they can cause disruptions to spacecrafts and power grids) The atmosphere is only capable of holding a minute fraction of this: water vapor. Resides mostly in troposphere! Water’s 3 phases: solid, liquid, gas; it is important for distribution of heat in the atmosphere. Ozone: a pungent blue gas that is highly concentrated in the stratosphere. The peak concentration of ozone occurs at an altitude of roughly 32 kilometers (20 miles) above the surface of the Earth. Concentration varies with season and latitude. It can react with many chemicals. It’s important because it protects the biosphere from potentially damaging doses of ultraviolet (UV) radiation. The Earth’s atmosphere: troposphere (where weather occurs and temperature declines with altitude) and stratosphere (temperature rises with altitude because ozone absorbs UV; less vertical component mixing). Ozone on land: Forms when nitrogen oxide gases from vehicle and industrial emissions react with volatile organic compounds (carbon-containing chemicals that evaporate easily into the air). Atmospheric CO2: emitted naturally and through human activities. It is either removed by oceans and growing plants or emitted back into the atmosphere through natural processes. The emission and removal is roughly equal when in balance. Keeling curve: a graph that shows how carbon dioxide (CO2) is accumulating in our atmosphere. CO2 measurement is often taken at Mauna Loa Observatory in Hawaii. Atmospheric concentrations of carbon dioxide fluctuate slightly with the change of the seasons, driven primarily by seasonal plant growth in the Northern Hemisphere. Sources of natural variable gases and materials: volcanoes, oceans, decaying plants, forest fires, plants and soil. Anthropogenic pollution: pollutions caused by human activities, industrialization, deforestation, and other land-use changes. Perihelion: the closest point of a body’s direct orbit around its sun (Earth) Aphelion: the farthest point of a body’s direct orbit around its sun The Inverse Square Law: The further you go, same energy spread over larger area (inversely proportional to distance squared) or E ~ 1/(r^2). The Sun Elevation Law: When the sun is high and perpendicular to earth, energy is more concentrated and thus is distributed over smaller area. If the sun is farther or lower in position, the same amount of energy is distributed over larger area. Seasons: caused majorly by orientation of the Earth towards the sun. Example: Northern Hemisphere has its winter when the Earth’s axis tilt to the left, the North receives less solar energy and it’s more spread out. Vice versa for Northern Hemisphere’s summer. Two factors determine the amount of solar energy received: The irradiance over a unit area depends on the angle between the overhead direction and the central ray to the sun; while it has an inverse relationship to the distance from the sun. Electromagnetic Waves: the energy transported from Sun to Earth. Why can we see rainbow? : different wavelengths of radiation encounter dense obstacle (prism: water, glass etc) and get refracted differently and emerge as colors. Albedo: solar radiation that is spread out and reflected back into the atmosphere by Earth. About 31% Radiation theory: All objects with a temperature above absolute zero (0 K on the Kelvin scale and as −273.15°C on the Celsius scale) emit radiation Stefan-Boltzmann Law: the amount of energy per square meter per second that is emitted by an object is related to the fourth power of its Kelvin temperature: E~(T^4) Wilhelm Wien’s law: the hotter an object, the shorter the wavelength of maximum emission of radiation λmax = 2900/T Does Earth emit radiation? Yes! The earth also emits radiation called terrestrial or long wave radiation which is less energetic than solar radiation. Convert from Fahrenheit to Celsius: °C x 9/5 + 32 = °F and (°F - 32) x 5/9 = °C Convert from Kelvin to Celsius: T(°C) = T(K) - 273.15 Convert from micrometer to meter: 1 micrometers (μm)=10^-6 m Solar Constant: S 0s the irradiance of solar energy received on a surface exposed normal to sun’s rays ( on) at the mean Earth-Sun distance and in absence of atmosphere. S = 1072 W/(m^2) Max Planck law: the energy of light is proportional to its frequency. E = hv in which h is Planck's constant. Solar Energy Spectrum: Basic climate model: combine the factors determining amount of solar energy received and Stefan-Boltzmann Law (for Earth’s radiance). When energy yielded equals that loses, this yields -18 C ; Actual value is 15 C.o Greenhouse effect: When the atmosphere trap/absorb more heat and increase temperature. These absorb part of the radiant energy that passes through and radiate it back to Earth: atmosphere, water vapor, oxygen and ozone, greenhouse gases. Global warming: a recent warming of the Earth's surface. It is predicted to be the result of an "enhanced greenhouse effect" mostly due to anthropogenic increases in atmospheric greenhouse gases. Spectrophotometer: measures the absorption of a light – its intensity as a function of its color (wavelength). Impact of clouds on temperature fluctuations: it both cools and heats the Earth. It can reflect solar energy back into atmosphere and emits long waves of energy and increase temperature below it. How is heat tranfered in the atmosphere? Through conduction, convection and radiation. Conduction is the transfer of heat between substances that are in direct contact with each other. Convection occurs when warmer areas of a liquid or gas rise to cooler areas in the liquid or gas. Radiation is a form of energy transport consisting of electromagnetic waves traveling at the speed of light (requires no contact; Heat can be transmitted though empty space by thermal radiation or infrared radiation). Negative energy feedback: when surface temperature increases and lowers itself by using its energy to radiate more infrared radiation to outgoing IR flux. Positive energy feedback: Includes water vapor in atmosphere! Surface temp and water vapor increases, thus trap more heat and increases the temp even more (greenhouse effect). Air pressure: pressure exerted by air pressing on objects. It can be measured using a mercury barometer. Atmospheric pressure varies with… temperature and altitude above sea level. What are those (seemingly) circular lines you see drawn on pressure map? Isobars – line of equal pressure. The pressure gradient increases with a decrease in distance among isobars. Pressure radiant concept: air will travel from high pressure region to that of lower pressure. 3-cell model for global wind pattern: Polar Easterlies is from 60-90 degrees latitude; Westerlies is from 30-60 degrees latitude; Tropical Easterlies is from 0-30 degrees latitude (aka Trade Winds). Hadley cell. Different forces that affect air movement: Coriolis force; the flow of air at upper atmosphere; the flow of air at the surface of oceanic water; jet stream. Jet stream: polar (50 and 60 degree N-S) and subtropical (20-30 degree) jet stream. Jet streams are like rivers of wind high above in the atmosphere (upper air flow). They typically run from west to east, separate colder air and warmer air; push air masses around, moving weather systems to new areas. They also don’t travel in straight lines but in patterns called peaks and troughs. Global warming causes these ups and downs become more extreme. Note on jet stream: it occurs because of contact between two different air temperature between the cold poles and the hot tropical region. The subtropical stream is not so potent because there’s a smaller difference between it and the middle region than that of the polar stream. Air pressure is lower in subtropical than in polar. Coriolis force: force created because Earth spin around its axis. This is why air does not move straight from high to low pressure area but likely to move perpendicular. It also makes wind to change its direction to the right in the northern Hemisphere and to the left in the Southern hemisphere. Also relate this to Newton’s second law: F=ma (F is force, m is mass and a is acceleration) Geostrophic wind: pretty much wind that is under both Coriolis force and pressure gradient force. Surface wind movement: dry, cool air sinks down while moist, hot warm (hotter) air rises. It flows clockwise (and diverge) around an area with high pressure and vice versa. In the upper atmosphere, in general, air tends to flow… parallel to isobars. The Bermuda High: a high pressure system located in the Atlantic Ocean. It has clockwise circulation that provides increased humidity throughout the summer months in the southeast US. During the winter months, the Bermuda High is located farther east of the US towards the middle of the Atlantic Ocean. This allows the jet stream to dip farther south into the southeast US. The Pacific High: similar to Bermuda high but it keeps the western coast of the United States relatively dry during the summer especially compared to locations along the East Coast. During the winter, the Pacific High moves farther south. Doldrums: also known as Inter-tropical Convergence Zone (ITCZ), is a low-pressure area around the equator where the prevailing winds are calm. They’re found around the equator. Horse latitudes: sub-tropic latitudes between 30 and 350 north and south. Under the influence of high pressure - an area which receives little precipitation and has calm winds. Locations of deserts: at 300 latitude and at descending branch of Hadley cell. El Nino: phenomenon in which there’s a rise in temp of water in eastern Pacific. Regions of climatic abnormalities associated with El Niño–Southern Oscillation conditions during December through February and during June through August. La Nina: phenomenon in which there’s a decrease in temp of water in eastern Pacific. El Niño (La Niña) is a phenomenon in the equatorial Pacific Ocean characterized by a five consecutive 3-month running mean of sea surface temperature (SST) anomalies in the Niño 3.4 region that is above (below) the threshold of +0.5°C (-0.5°C). This standard of measure is known as the Oceanic Niño Index (ONI). Warm and cold phases are defined as a minimum of five consecutive 3-month running mean of SST anomalies (ERSST.v4, 1971-2000 base period) in the Niño 3.4 region surpassing a threshold of +/- 0.5°C. An index value between 0.5 and 0.9 is considered weak; between 1.0 and 1.4 is considered moderate, and of 1.5 or greater is considered strong. Latent heat: the heat (energy) required for water to change its phases. Absolute humidity: mass of water vapor/volume of air (g/m ). 3 Specific humidity: mass of water vapor/total mass of air (g/kg). The larger the parcel, or Volume, with similar mass of water vapor, the smaller the absolute humidity but the specific humidity does not change. Saturation vapor pressure: increases as temperature increases. Equilibrium in which water vapor molecules evaporate in atmosphere equals those that condense into water. Clausius-Clapeyron relation: The vapor pressure of any substance increases non-linearly with temperature. Atmospheric pressure boiling point: the temperature at which the vapor pressure equals the surrounding atmospheric pressure. Relative humidity: = (actual vapor pressure/saturation vapor pressure)*100. When the air is cool (morning), the relative humidity is high. When the air is warm (afternoon), the relative humidity is low. Rising of moist air leads to formation/condensation of clouds. Example: Cumulus clouds form as hot, invisible air bubbles detach themselves from the surface, then rise and cool to the condensation level. Below and within the cumulus clouds, the air is rising. Around the cloud, the air is sinking. Rain shadow effect: picture a mountain. The warm, moist air rises and form clouds (as temp decreases) and lead to precipitation. After it reaches over the top of the mountain and being cooled, it ascends down to the other side of the mountain as cool, dry air. This cause one side of the mountain having plenty of precipitation and plant growth while the other have dry climate. Volcanic activity injects water into the atmosphere (so then it condenses and turns into precipitation – cool explanation) Water cycle: water is constantly moving Oceans contribute to about 90% of evaporated water (makes sense) and the rest is due to plant transpiration. Evapotranspiration: combination of evaporation of precipitation and plant transpiration. Factors that affect transpiration: temperature, relative humidity, wind and air movement, soil moisture content and types of plants. See if you can understands the movements present in the image above. If you’re unsure, check back to Lecture 8 slide #21 and #22 for details! Water reservoirs: ice and glaciers, streams and rivers, lakes and oceans, ground water storage (infiltration). Distribution of global water: mostly oceanic water (96.5%), the rest is saline ground water (0.93%) and fresh water. So you can see we actually have very limited unsalted water. Of the fresh water reservoirs, a large portion (68.6%) is ice caps and glaciers, 30.1% is ground water and only 1.3% is surface water. The circulation of surface oceanic water is driven by wind while that under deep water is driven by differences in water density. There’s kinetic energy between wind and surface ocean water (less than 1km deep) as it blows across. This sets the surface water in motion, creating waves and currents. Wind-generated currents transport large volumes of water and thermal energy across the oceans Ocean currents also undergo Coriolis force so they either flow horizontally around equator, around at about 20-60 degree latitude or from cold to warm and vice versa between poles and warmer regions. Horizontal oceanic circulation helps to erase radiation imbalances by exporting excess energy from the tropics. Both atmosphere and ocean helps transporting heat to higher latitude Coastal Upwelling: the phenomenon in which The wind along the west coast moves upper water along the coast away from the coast which allows colder water from below to come up reducing the temperature of the water. Ekman Spiral: caused by Coriolis force. When surface water molecules move by the force of the wind, they, in turn, drag deeper layers of water molecules below them. Each layer of water molecules is moved by friction from the shallower layer, and each deeper layer moves more slowly than the layer above it, until the movement ceases at a depth of about 100 meters. Like the surface water, however, the deeper water is deflected by the Coriolis effect - to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. As a result, each successively deeper layer of water moves more slowly to the right or left, creating a spiral effect. Because the deeper layers of water move more slowly than the shallower layers, they tend to “twist around” and flow opposite to the surface current. (Phew!) Like isobars, the lines marked on ocean water surface that represent equal temperature are called isotherms. The circular motion of currents you see on map are called gyres (see image below): Some currents you need to know: boundary currents that flow parallel to the coast. This consist of Western boundary currents on the western edge of the oceans as fast, narrow jets and Eastern boundary currents on the eastern edge of the oceans as weaker currents Ocean circulation transfers heat from the tropics toward the poles, moderating middle and high- latitude climates. (See examples in Lecture 9 slide #13-14) Unlike surface water, deep water current is monitored by differences in water density that is caused by variations in temperature (thermocline – area of rapid transition, especially in temp) and salinity (Halocline - a strong, vertical salinity gradient) Salinity increases while thermocline (temp) decreases as we go deeper into oceans, so density increases with salinity. Density also goes up as we go deeper; this is called pycnocline Because deep-ocean circulation depends on temperature and salinity, this circulation is referred to as thermohaline circulation The salts contained in seawater are largely the result of the weathering of crustal rocks. Oceans are not getting saltier, which means the amount of salts removed and added into oceans reach equilibrium. The combination of low temperatures and high salinities results in very dense water that sinks and flows down the slope of the basin and spreads toward the equator as the bottom layer of water in the deep-ocean basins T hermohaline conveyor belt: movement of deep water globally. The ocean conveyor gets its “start” in the Norwegian Sea, where warm water from the Gulf Stream heats the atmosphere in the cold northern latitudes. This loss of heat to the atmosphere makes the water cooler and denser, causing it to sink to the bottom of the ocean. As more warm water is transported north, the cooler water sinks and moves south to make room for the incoming warm water. This cold bottom water flows south of the equator all the way down to Antarctica. Eventually, the cold bottom waters return to the surface through mixing and wind-driven upwelling, continuing the conveyor belt that encircles the globe. The deeper ocean is relatively rich in nutrients. The thermohaline circulation transports nutrient- rrich waters around the globe, returning the nutrients to the surface in areas of upwelling We also need to look at some of the culprits of global warming. Here comes CO ! The l2rge reservoirs of this gas is NOT in atmosphere but in fact in rocks (limestone, dolomite, sediment), dissolved CO2 in deep ocean water, fossil fuel, ocean sediment, decaying matter and soil. (Amount measured in Gton) Combustion of natural gas = CH + 24O → CO 2 2 H O 2 2 Combustion of coal and oil = Coal/Oil + 2 O → C2 + 2 H O2 2 Methane gas: flammable hydrocarbon gas that isthe chief constituent (up to 99 percent) of natural gas; is one of the major greenhouse gases Hydrocarbon: organic compound made of carbon and hydrogen and found in coal, crude oil, natural gas, and plant life. Emission of gases resulting from combustion of hydrocarbons is a major cause of air pollution and global warming. One anthropogenic CO2 emission: deforestation. Gases are emitted from burning of plants and soil (and of exposing CO2-rich soil layer) while O2 source is decreased. CO2 can be removed by these processes: planting trees and restoring forests, photosynthesis, dissolution of it in ocean, dissolution of carbonate sediment in ocean floor Half of our oxygen comes from Phytoplankton in a process that removes carbon dioxide from the atmosphere and converts it into organic carbon to fuel nearly every. CO2 can react chemically with precipitation to form a weak carbonic acid that can weather rocks and increase ocean acidity. Not good for organisms! Surface water can exchange CO2 rapidly with atmosphere but only temporarily (about 8 – year period). Deep water exchange is much slower. Oceans also are only capable of dissolving a finite amount of CO2. Dissolution of Carbonate Sediments on Sea-Floor also happens very slow and only for a short period of time (see Lecture 10 for more details)
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'