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Atmospheric Chemistry Glossary


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Fauna - Animals or animal life of a particular region or a particular time. [New Zealand Journal of Zoology; v15; 577; 1988.] [Biological Conservation; v46; 169; 1988.] [Palaeogeography, Palaeoclimatology, Palaeoecology; v305; 264-279; 2011; DOI:10.1016/j.palaeo.2011.03.007]

Feedback Cycle - The increase of the input into a system, which produces a negative or a positive output in a system of interlocking components; the return of a part or the effects of the output to the input. A proposed positive feedback cycle involves the outgassing of carbon dioxide from the planet's oceans: Since CO2 solubility in water decreases with temperature and since CO2 is a greenhouse gas, a positive (and possibly runaway) feedback cycle might involve the following: increased greenhouse warming of the atmosphere by IR absorbing CO2 in the gas phase--and the subsequent heating of the oceans--could increase the amount of carbon dioxide released into the atmosphere from the oceans. This might thereby increase greenhouse warming, which would, in turn, again heat the atmosphere and the ocean, etc. This is an amplification of the input: positive feedback: leads to more warming. Though the process is no doubt more complicated than this, a runaway greenhouse effect is usually given as the reason for Venus' high surface temperatures so a planet-wide process of this type is not unknown.

Conversely, a negative feedback cycle might consist of the increase in release of dimethyl sulfide (DMS) by ocean surface microorganisms whose population is increased by ocean warming. DMS oxidation in the troposphere leads to sulfate aerosol formation which act as cloud condensation nuclei in the marine troposphere. Increased CCN would increase cloud albedo which increases reflect incoming solar radiation, thereby cooling the oceans. This is an dampening of the input: negative feedback: leads to termination of the original warming. [Water, Air, Soil Pollution.; v70; 615; 1993.] [Tellus B; v43; 152–163; 1991; DOI:10.1034/j.1600-0889.1991.t01-1-00013.x] [Atmospheric Environment; v39; 2089-2110; 2005; DOI:10.1016/j.atmosenv.2004.12.029]

Fermentation - A type of anaerobic respiration which uses atoms other than oxygen as the final electron acceptor. Fermentation occurs in bogs and marshes resulting in the production of CH4 and CO2 as well as other compounds such as ethanol, lactic acid, butyric acid, and acetone. [Biochemical Engineering Journal; v27; 110-119; 2005; DOI:10.1016/j.bej.2005.08.015] [Atmospheric Environment; v42; 7786-7794; 2008; DOI:10.1016/j.atmosenv.2008.04.052]

Firn - Granular, porous snow that has endured a summer without melting and will transform into glacial ice. In greenland this layer approaches 80 meters thick and can act as a storage place for meltwater percolating down from the surface. [Nature Climate Change; 2016 DOI:doi:10.1038/nclimate2899] [Washington Post, Jan 4, 2016] [Annals of glaciology; v18; 208; 1993.] [Cold Regions Science and Technology; v21; 295; 1993; DOI:10.1016/0165-232X(93)90072-G] [Earth Planetary Science Letters; v293; 359-367; 2010; DOI:10.1016/j.epsl.2010.03.003]

Fixed Gases - The gases in earth's atmosphere whose concentrations are considered stable or invariable. This includes gases such as O2, N2, and the noble gases, as opposed to variable gases such as CH4 and CO2 whose concentrations change because of reactivity or because there are large atmospheric sinks such as vegetation in the case of CO2. [Chemical Geology; v176; 1-30; 2001; DOI:10.1016/S0009-2541(00)00405-8]

Flora - A plant or plant life of a specific region or particular period. [Madrono; v35; 202; 1988.] [Blumea; v33; 395; 1988.] [Review Palaeobotany Palynology; v144; 181-219; 2007; DOI:10.1016/j.revpalbo.2006.07.003]

Flue Gas - Gaseous chemical products from combustion-based power plants using hydrocarbons such as coal or natural gas as fuels. This is the exhaust from the chemical reactions that provides the heat to boil water to turn turbines to produce electricity. Historically between 3 and 15% of power plant flue gas is carbon dioxide. This definition is not strictly accurate becase flue gas could be any gaseous products exhausted from an inductrial process. [International Journal of Greenhouse Gas Control; v2; 9-20; 2008; DOI:10.1016/S1750-5836(07)00094-1]

Flux - The rate of continuous change, flow or movement of liquid, particles or energy. The rate of discharge of a liquid, removal of energy or particle depositing from one body to another. For example, flux emissions of sesqiterpines from vegetation was estimated to be 10-40 mg per square meter in a summer month of the western and southern US states. [Environmental Science Technology, v41; 1545–1553; 2007; DOI:10.1021/es0618907] [Journal of Alloys and Compounds; v195; 407; 1993.] [Ecological Monographs; v58; 177; 1988.]

Fly Ash - A byproduct from the process of burning finely ground coal in an electric power generating plant. Fly ash composition is mainly spherical glassy silica particles released after the combustion cycle through exhaust gases. It's composed of additional elements that form mostly oxidized compounds that condense when they cool down from the combustion process. In December 2008, 2.6 million cubic yards of fly ash sludge stored in a large retaining pond at a coal-fired power plant near Kingston, TN was released when a retaining dike failed. The sludge was found to contain arsenic, mercury, cadmium, chromium, thallium, and lead, and these toxic metals were found in the river(s) water in which the sludge spilled. [New York Times Dec 26, 2008] [Resources, Conservation and Recycling.; v31; 217-228; 2001; DOI:10.1016/S0921-3449(00)00084-7]

Foehn - A warm, dry wind on the lee side of a mountain range that owes its relatively high temperatures largely to adiabatic heating during descent down mountain slopes, a descent that compresses and thereby heats the air (see Lapse Rate). In Zurich, Switzerland this means a warm but clear view of the Alps. [Frederick K. Lutgens and Edward J. Tarbuck, The Atmosphere (5th Edition), Prentice-Hall, 1992[.

Fog - The state in which particles of very small water droplets are in contact or close to the earth's surface, generally reducing horizontal visibility. [Aviation Weekend Space Technology; v130; 27; 1989.] [Audubon; v90; 44; 1988.] [Atmospheric Environment; v45; 2559-2568; 2011; DOI:10.1016/j.atmosenv.2011.02.016]

Formaldehyde - CH2O, A colorless, pungent, carcinogenic, and toxic gas which can irritate membranes. It is used as formalin in its aqueous state (37 %). Formaldehyde is reactive due to its carbonyl functional group. In the oxidation of hydrocarbons in the atmosphere, formaldehyde is one of many aldehydes that is produced especially in urban environments. [Environmental Chemistry; Manahan Stanley E.; Lewis Publishers; Boca Raton; Florida; page 689; 1994.] [Environmental Chemistry; Moore, John W., et al; Academic Press; New York; page 49; 1976.] [Atmospheric Environment; v45; 1888-1895; 2011: DOI:10.1016/j.atmosenv.2010.12.024]

Formic Acid - CH2O2, A weak acid that photolytically reacts in the atmosphere forming COOH radical and H radical. This compound often reacts with the hydroxyl radical and atomic oxygen to form formic acid and a hydroperoxy radical. This is a sink for the hydroxyl radical and it also helps drive other reactions with the addition of hydroperoxy radicals to the atmosphere. [Graedel and Crutzen, Atmospheric Change An Earth System Perspective. 1993. Pgs. 121 and 158.]

Fossil Fuels - There are coal, crude oils, oil shales, tar sands and natural gases such as butane, ethane, methane which occur naturally from the decomposition of plant and sea and land organisms over millions of years. These natural resources contain stored energy from the sun which is released upon combustion. These fuels also release various types of pollutants such as sulfur dioxide, carbon dioxide and nitrogen dioxide when burned. [Living in the Environment; Miller, G. Tyler; Wadsworth Publishing Company; Belmont, California; pages 476-486; 1992.] [Atmospheric Change; Graedel, T. E.; W. H. Freeman and Company; New York; page 430; 1993.]

Free Radicals - Highly reactive atoms or molecules with incomplete (electronic) octets and therefore uneven numbers of electrons. (In the case of hydrogen radical this is an incomplete duet.) Free radicals species are very electrophilic, will abstract atoms from other molecules to complete their octets, and will, in the process, generate new radicals. In the atmosphere, most free radical species have short life times; however, they can promote the conversion of oxygen to ozone and also take part in the catalytic cycle of ozone destruction (see chlorine and chlorine monoxide). (Also see radicals.) [Organic Chemistry; Wade, L. G.; Prentice-Hall, New Jersey; page 125; 1991.] [Atmospheric Change; Graedel, T. E. ; W. H. Freeman and Company; New York; page 141; 1993.]

Freons (also see CFCs) - Stable liquids or gases usually produced for solvents, aerosol propellants, refrigeration, air conditioner or styrofoam purposes. These high vapor pressure liquids/gases are chemically stable and have long atmospheric lifetimes; therefore, they can eventually become well-mixed in the troposphere and ultimately diffuse into the stratosphere. Upon encountering high energy UV light in the upper stratosphere these species are photodissociated and ultimately release all of their atoms there. The free radical chlorines (or bromines in the case of some halons) catalytically destroy ozone (see chlorine) in the stratosphere. [Environmental Chemistry; Manahan, Stanley E.; Lewis Publishers; Boca Raton, Florida; page 418; 1994.] [The Chemistry of Our Environment; Horne, R. A.; John Wiley and Sons; New York; page 195; 1978.]

Front - The marked boundaries of two air masses of differing densities. The difference in densities can be related to temperature, pressure or humidity. [Atmospheric Environment; v39; 1497-1511; 2005.]

Frontal Wedging - The lifting of air resulting when cool air acts as a barrier over which warmer, lighter air will rise. [Atmospheric Environment; V38; 6999-7008; 2004; DOI: 10.1016/j.atmosenv.2004.02.070]

Fugitive Dusts - A term used to describe indirect air pollution caused primarily from dust and dirt loosened from dirt roads. This dust can cover large areas and is predominantly found in rural areas and construction sites. [Atmospheric Environment; v43; p889-886; 2009; DOI:10.1016/j.physletb.2003.10.071]


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Gaia Hypothesis - An hypothesis proposed during the early 1970s by James Lovelock which states that all living organisms have the ability to affect their surroundings such as the atmosphere, lithosphere, and climate to maximize its biological success. The hypothesis connects the evolution and survival of a species to the evolution and conditions of its environment. [Scientists on Gaia; Stephen Schneider et al; MIT Press; Cambridge, Mass.; pages 4-7, 62; 1991.] [Atmospheric Change; Graedel, T. E.; W. H. Freeman and Company; New York; page 418-421; 1993.] [ Nature; v406; 685-686; 2000.]

Gas Constant - A physical constant used in the simplified ideal gas law equation (PV=nRT). In chemistry, the gas constant is most often represented by the letter R. [Fluid Phase Equilibria.; v253; p124-129; 2007; DOI:10.1016/j.fluid.2007.02.008]

Gasoline - An oil derived hydrocarbon mixture used as fuel in internal combustion engines. In the US more than 40% of carbon dioxide emissions come from transportation engines burning gasoline. [Atmospheric Environment; V40; 8002-8019; 2006.]

General Circulation Models - Three dimensional computer simulations of climate and weather which, through calculations, are used to investigate gravity wave fields. The models may help to predict atmospheric chemistry distribution and meteorological trends for the future. [Atmospheric Change; Graedel, T. E.; W. H. Freeman and Company; New York; page 327-8; 1993.] [Coupling Processes in the Lower and Upper Atmosphere; Edited by Eivind W. Thrane; Kluwer Academic; Boston; page 161; 1993.]

Geologic Time Scale - A time scale in which the earth and its atmosphere are dated. It is broken into two division; Relative Time: Determines the age relative to other surrounding objects; Absolute Time: Obtained with radiometric dating of the object. [Holmes, A, 1937. The Age of the Earth. (New Edition Revised). Nelson: London, p.1-263.] [Harland, W.B.; Armstrong, R.L.; Cox, A.V.; Craig, L.E.; Smith, A.G.; and Smith, D.G.; 1990: A geologic Time Scale, 1989 Edition. Cambridge University Press. Cambridge, p1-50.]

Geostrophic Wind - A wind forming from the apparent Coriolis and pressure gradient forces along straight isobars above the boundary layer. [Atmospheric Environment; v39; 1739-1748; 2005.]

Geothermal Energy - An alternative energy source that uses the earth's interior heat as the primary energy source for the generation of electricity. Alternative here refers to different from historical sources of energy, that is, hydrocarbons. [Geothermics; v32; 379-388; 2003.]

Gigayears - Time measured in billions of years; a common measure of geologic time. [Proceeding of the National Academy of Sciences U.S.A; v85; 6577-6580; 1988.]

Glaciation - The process of forming glaciers. [Proceeding of the National Academy of Sciences U.S.A; v99; 12567-12571; 2002.]

Glacier - A slow-moving mass of ice formed in higher latitudes and elevations. When snowfall is greater than melting and the increasing amounts of snow become compacted and pressurized it forms firn (see above) and ultimately a glacier. As the glacier moves, it carries rocks and soil, and can form u-shaped valleys over geologic time. Glaciers can move at variable rates. [Ecological Monographs; v64: pp. 149-175: 1994.] [Geological Society of America Bulletin; v103: pp. 1073-1089: 1991.]

Global Climate Change - Change in the average global surface temperature, precipitation level, seal level, arctic sea ice, etc. Global climate change can be affected directly or indirectly by anthropogenic processes such as fossil fuel combustion and can also be influenced by natural occurrences. Most significant are changes in the atmospheric concentrations of atmospheric water vapor, CO2, CH4, N2O, and CFCs. Also see Global Warming. [Global Environmental Change.; v13; p295-306; 2003; DOI:10.1016/S0959-3780(03)00051-7] [Journal of Glaciology; v56; 1115-1121; 2010.]

Global Climate Model - A computer program that is used by atmospheric scientists to study and predict world-wide trends in weather patterns and the forces and physical laws that affect climate. The formulae are complicated and require skilled mathematicians, atmospheric scientists, and powerful computers for execution. Five regimes that influence climate are often taken into consideration: atmosphere, hydrosphere, biosphere, cryosphere, and pedosphere. Atmospheric and environmental physical laws as well as principles of thermodynamics and hydrodynamics are all used as part of the extensive mathematical parameters for the program. The results of these models are used as reference for other models, policy decisions, and by meteorologists. [Climate Change; v23: pp. 337-377: 1993.] [Climate Change; v21: pp. 345-346: 1992.]

Global Warming - The overall increase of the Earth's atmospheric temperature due to a buildup of greenhouse gases. In spring 2007 research predicted that the earth's Arctic Ocean might be completely ice-free at the end of the summer by the year 2020; however, ice would return in the winter. In 2010 research posed that September Arctic ice thickness was changing by >10% per decade. The year 2014 was the warmest year in the global temperature record since 1880. And the 10 warmest years since 1880 ocurred since 1997. See also Global Climate Change. [Geophysical Research Letters; v34; L09501; 2007; DOI:10.1029/2007GL029703.] [The economics of global warming; William Cline; 1992; Institute for International Economics; Washington D.C.] [Global Warming and biological diversity; Robert Peters; 1992; Yale University Press; New Haven.] [Journal of Glaciology; v56; 1115-1121; 2010.] [New York Times; Jan 16; 2015.]

Glycolic Aldehyde - (C2H4O2), also called hydroxyacetaldehyde, is formed during the oxidation of ethane and isoprene, and also by the emission of biomass fires. It is the simplest form of sugar. Glycol aldehydes have also been found in trace amounts in dust clouds near the Milky Way of outer space. [Journal of Geophysical Research; v.D13, page 8469. 2003] [JGR-Atmospheres; V.104, No D17, pages 21, 237.1999.]

Gondwanaland - A hypothetical supercontinent comprising approximately the present continents of the southern hemisphere. See also Pangaea. [Earth-Science Reviews; V68; 1-132; 2004.] [Journal of Asian Earth Sciences; v34; 227-244; 2009. DOI: 10.1016/j.jseaes.2008.05.011]

Gravity - A natural force exerted on a body toward the earth's surface or between two bodies. Gravity has a strong effect on how matter interacts. Gravitational attraction depends on the masses of the bodies involved and the distance between them. Centrifugal force caused by the earth's rotation on its axis tends to lessen the force of gravity. [A Journey into gravity and spacetime; John Archibald; 1990; Scientific American Library; New York.] [Gravity, deformation, and the earth's crust: in theory, experiments, and geological application; Hans Ramberg; 1981; Academic Press; London.]

Greenhouse Effect - The phenomenon in which outgoing infrared radiation that would normally exit from a planet's atmosphere but instead, is trapped or reflected because of the presence of the atmosphere and its components (see below) is called the greenhouse effect. It has been calculated that this effect is necessary to maintain the earth's climate and surface temperature and, more importantly, the liquid state of water in the majority of the earth's biosphere; however, the best scientific estimates to date suggest that increasing amounts of greenhouse gases are resulting in higher temperatures worldwide. This could result in melting of icecaps that would raise the sea level and cause devastating floods in coastal areas, more extremes in rainfall and intensity, and the distribution of species in the biosphere. [The Greenhouse Effect; Matthew Kreljic, ed.; 1992; HW Wilson Co.; New York.] [Climatic Change; v20: p. iii-vii: 1992.]

Greenhouse Gases - Those atmospheric components that absorb strongly in the infrared region of the spectrum. Infrared radiation is reflected and emitted by the earth's surface as heat and causes a fairly large warming effect when trapped by these gases in the atmosphere. In order of abundance and importance as greenhouse gases are water vapor, carbon dioxide, ozone, nitrous oxide, methane, and chlorofluorocarbons (CFCs). The U.S. EPA provides a tool for mapping CO2 equivalents emission in the United States-for all those greenhouse gases except water-here. Absorption by water vapor, the most common greenhouse gas, explains why many humid or cloudy days feel much hotter than dry, clear days of the same air temperature. Because of these gases, only about 5% of the radiation escapes from the atmosphere while more than 90% is radiated back to the surface of the earth. [Geoderma; v135; 49-62; 2006.]

Greenhouse Warming - See global warming [Policy implications of greenhouse warming; Committee of Science, Engineering, and Public Policy; 1991; National Academy Press; Washington D.C.] [Greenhouse warming: negotiating a global regime; Richard Elliot Benedick; 1991; World Resources Institute; Washington D.C.]

Gulf Stream - The Gulf Stream is a powerful current in the Atlantic Ocean. Its movement is related to density redistribution, differences in temperature, the Earth's rotation, and wind currents. Beginning in the Gulf of Mexico, it flows along the east coast of North America and across the Atlantic to Europe. The Gulf Stream carries warm water from the tropics and warms the climate of the land near where it passes. The relatively temperate weather in Great Britain is, to a large degree, controlled by the Gulf Stream redistributing energy from equatorial solar radiation to the North Atlantic. [Journal of Marine Research; v 52; p.797-836; 1994] [Journal of Marine Research; v 52; p. 837-863; 1994.]

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