PmUE{c @ @i @09@iTable1ColA1 ColB1ColA2ColB2 @ &aASynonymous with acidic deposition. Both are somewhat inaccurate versions of the phrase "deposition of acidifying substances from the atmosphere." Acidity is measured as the concentration of hydrogen ion (H+), in logarithmic pH units. Solutions having pH < 7.0 are acidic, but "acid rain" is usually considered to have pH < 5.65 because of the natural influence of carbonic acid in precipitation.*AThe predominately horizontal large-scale movement of air that causes changes in temperature or other physical properties. In oceanography, advection is the horizontal or vertical flow of sea water as a current. Transport of a property by fluid motion; in meteorology, referring to horizontal flow.AParticulate material, other than water or ice, in the atmosphere ranging in size from approximately 10E-3 to larger than 10E2 micrometers in radius. Aerosols are important in the atmosphere as nuclei for the condensation of water droplets and ice crystals, as participants in various chemical cycles, and as absorbers and scatterers of solar radiation, thereby influencing the radiation budget of the earth-atmosphere system, which in turn influences the climate on the surface of the Earth.AIncreased reflectivity of the ground surface following removal of the vegetation (desertification) thereby changing the heat balance of the surface-atmosphere system and, although unproven, assumed by some meteorologists to result in less uplift and less rain.SAA period of high temperatures, particularly the one from 8000 to 4000 BP (before the present era), which was apparently warmer in summers, as compared with the present, and with the precipitation zones shifted poleward. More rainfall occurred in most of the subtropical United States and Scandinavia. Also called the hypsithermal period.H &M&"y).8 absorption coefficientA measure of the amount of radiant energy, incident normal to a planar surface, that is absorbed per unit distance or unit mass of substance. accessory cloudA cloud which is dependent on a larger cloud system for development and continuance. Roll clouds, shelf clouds, and wall clouds are examples of accessory clouds.  acid rain acid shockShort-term event of great acidity that occurs in freshwater systems receiving intense pulses of acidic water when the snowpack melts. acidificationIncrease over time in the content of acidity in a system, accompanied by decreases in the acid-neutralizing capacity due to alkalinity and decreases in calcium and magnesium content. active species`Trace constituent in the stratosphere that is directly involved in catalytic ozone destruction. adiabatic processA thermodynamic change of state of a system such that no heat or mass is transferred across the boundaries of the system. In an adiabatic process, expansion always results in cooling, and compression in warming. advection*aerosol agglomerationIn meteorology, the process by which precipitation particles grow larger by collision or contact with cloud or other precipitation particles. air pollutionOne or more contaminants in concentrations or durations that are injurious to human, animal, plant, and property or that impair the enjoyment of life or property. airborne particulatesTotal suspended matter found in the atmosphere as solid pieces or liquid droplets. Airborne particulates include windblown dust, emissions from industrial processes, smoke from the burning of wood and coal, and the exhaust of motor vehicles. airmassA widespread body of the atmosphere that gains certain meteorological or polluted characteristics while set in one location. The characteristics can change as it moves. albedoVThe fraction of the total solar radiation incident on a body that is reflected by it. albedo effectaltithermal period SwBThe largest circulation feature in the ocean in terms of both its sustained transport and its length. Whereas both the North Atlantic and North Pacific have distinct subpolar gyres, the southern hemisphere systems are masked by the circumglobal flow of the Antarctic Circumpolar Current, which is more similar to unbounded atmospheric flows. Also know as the West Wind Drift in reference to its general orientation down the prevailing winds. The availability of a more or less continuous circumglobal channel at approximately 55-60 S allows the current to connect the three major ocean basins -- Atlantic, Pacific, and Indian.CA persistent winter diffuse layer in the Arctic atmosphere whose origin may be related to long-range transport of midlatitude continental man-made pollutants. Industrial air pollution transported to the Arctic from mid- and high-latitude sources; primarily composed of sulfur compounds, visible as a yellow-brown layer over most of the Arctic mainly during the months of February, March, and April. The haze, first observed in 1957, is a result of pollution from Europe and Asia that migrates north in the late winter and spring. It grew yearly until 1982, then began a decline that probably stems from Russia's increased reliance on natural gas instead of coal and oil, as well as tighter pollution controls in western Europe. As of 1993, the haze had declined to about half its 1982 value.AClimate or region where the precipitation is barely sufficient to support vegetation. Aridity (also hyperaridity and semiaridity) may be defined by means of climatic diagrams or by various aridity indices (formulae involving precipitation, evapotranspiration, and temperature). Sometimes characterized as receiving either 80-150 mm or 200-350 mm annual precipitation, depending on the climatic regime.2BWinds which shift in a counterclockwise direction with time at a given location (e.g. from southerly to southeasterly), or change direction in a counterclockwise sense with height (e.g. westerly at the surface but becoming more southerly aloft). The opposite of veering winds. In storm spotting, a backing wind usually refers to the turning of a south or southwest surface wind with time to a more east or southeasterly direction. Backing of the surface wind can increase the potential for tornado development by increasing the directional shear at low levels. 3HN!*9. annual flood series8Maximum instantaneous discharge in each year of record.Antarctic Circumpolar Current w Antarctic ConvergenceSharp oceanographic boundary between latitudes 50 S and 60 S in the southern ocean, separating colder and less saline waters around the Antarctic continent from warmer and denser waters to the north. anthropogenicLiterally, "giving rise to humanity," but more commonly used to signify "human-induced." Usually used in the context of emissions that are produced as the result of human activities. anticycloneAn atmospheric high-pressure closed circulation with clockwise rotation in the Northern Hemisphere, counterclockwise in the Southern Hemisphere, and undefined at the Equator. Arctic haze arid  assimilation2Process of CO2 fixation by photosynthetic tissue. atmosphere (the)The envelope of air surrounding the Earth and bound to it by the Earth's gravitational attraction. Studies of the chemical properties, dynamic motions, and physical processes of this system constitute the field of meteorology. atmosphere (unit) standard unit of pressure representing the pressure exerted by a 29.92-in. column of mercury at sea level at 45 latitude and equal to 1000 g/cm2. atmospheric turbulenceA state of the flow of air in which apparently random fluctuations occur in the air's instantaneous velocities, often producing major deformations of the flow. atmospheric windowyThe spectral regions between 8.5 and 11.0 microns where the atmosphere is essentially transparent to longwave radiation. available soild moistureThat portion of the total water held in the soil that can be extracted for use by the plant, i.e., with a water potential usually above -1.5 mPe. backing winds2 baroclinic wavesAtmospheric waves with wavelengths of about 1000 km which draw their energy from the energy accumulated due to the north-south global temperature differences. baroclinitykHorizontally varying density along an isobaric surface, mostly due to the horizontal temperature gradient.,AProcess by which ice crystals grow at the expense of supercooled water droplets, coexisting in a cloud with temperatures below 0 C. Because vapor pressure over water is greater than over ice at a common temperature, if supercooled water is sufficiently available, ice grows at the expense of water.gAA radar echo which is linear but bent outward in a bow shape. Damaging straight-line winds often occur near the "crest" or center of a bow echo. Areas of circulation also can develop at either end of a bow echo, which sometimes can lead to tornado formation -- especially in the left (usually northern) end, where the circulation exhibits cyclonic rotation. AA non-dimensional number relating vertical stability and vertical shear (generally, stability divided by shear). High values indicate unstable and/or weakly-sheared environments; low values indicate weak instability and/or strong vertical shear. Generally, values in the range of around 50 to 100 suggest environmental conditions favorable for supercell development. Abbreviated BRN.3BA family of inert nontoxic and easily liquified chemicals used in refrigeration, air conditioning, packaging, and insulation or as solvents or aerosol propellants. Because they are not destroyed in the lower atmosphere, they drift into the upper atmosphere where their chlorine components destroy ozone. Abbreviated CFC. A compound containing only chlorine, fluorine, and carbon commonly used as a refrigerant, a cleaning agent, and a blowing agent for plastic foams; in the stratosphere CFCs decompose to release chlorine, which can catalyze ozone destruction.yAHigh-level clouds (16,000 feet or more), composed of ice crystals and appearing in the form of white, delicate filaments or white or mostly white patches or narrow bands. Cirrus clouds typically have a fibrous or hairlike appearance, and often are semi-transparent. Thunderstorm anvils are a form of cirrus cloud, but most cirrus clouds are not associated with thunderstorms. AA local region of clearing skies or reduced cloud cover, indicating an intrusion of drier air; often seen as a bright area with higher cloud bases on the west or southwest side of a wall cloud. A clear slot is believed to be a visual indication of a rear flank downdraft. E4~M$@: ( Benard cellCConvection cells that occur in unstable fluids, initially at rest.Bergeron process, bimodal distribution=A size or mass spectrum that has two peaks of concentration. biome7Landscape unit with its own climate, flora, and fauna. bipole`Organized pattern of locations for cloud-to-ground lightning of positive and negative polarity. black stratusMist particles, produced in trade-wind clouds, that are too small to fall rapidly and that scatter light over a very narrow angle. boreal forestNorthern forest or taiga (Russian term), covering large areas in the subarctic but extending well north of the Arctic Circle, dominated by coniferous trees. boundary layeraRegion where influence of boundary is important to flow solution -- generally a very thin layer.bow echog brightness temperatureApparent temperature of an object based on its radiative brightness. It equals the thermometric temperature when the object emissivity equals 1.Bulk Richardson Number catalytic processChemical reaction or set of reactions that is enhanced by the presence of some trace species that is neither created nor destroyed in the overall process.chlorofluorocarbons3cirrusy Clausius-Clapeyron relationfPhysical law relating the temperature and the equilibrium vapor pressure (or vapor density) of water. clear slotCThe statistical collection and representation of the weather conditions for a specified area during a specified time interval, usually decades, together with a description of the state of the external system or boundary conditions. The properties that characterize the climate are thermal (temperature of the surface air, water, land, and ice), kinetic (wind and ocean currents, together with associated vertical motions and the motions of air masses, aqueous humidity, cloudiness and cloud water content, groundwater, lake lands, and water content of snow on land and sea ice), and static (pressure and density of the atmosphere and ocean, composition of the dry air, salinity of the ocean, and the geometric boundaries and physical constants of the system). These properties are interconnected by the various physical processes such as precipitation, evaporation, infrared radiation, convection, advection, and turbulence.-BThe long-term fluctuation in temperature, precipitation, wind, and all other aspects of the Earth's climate. External processes, such as solar-irradiance variations, variations of the Earth's orbital parameters (eccentricity, precession, and inclination), lithospheric motions, and volcanic activity, are factors in climatic variation. Internal variations of the climate system also produce fluctuation of sufficient magnitude and variability to explain observed climate change through feedback processes interrelating the components of the climate system.wAThe period in history from about 5000 to 2500 BP during which surface air temperatures were warmer than at present in nearly all regions of the world. In the Arctic region, the temperature rose many degrees, and in temperate regions the increase was 1.0-1.7 C. In this period, glaciers and ice sheets receded greatly, and the melt-water raised sea level by about 3 meters.LAReflectivity that varies from less than 10 to more than 90 percent of the insolation and depends on drop sizes, liquid water content, water vapor content, thickness of the cloud, and the sun's zenith angle. The smaller the drops and the grater the liquid water content, the greater the cloud albedo, if all other factors are equal.BThe coupling between cloudiness and surface air temperature in which a change in surface temperature could lead to a change in clouds, which could then amplify or diminish the initial temperature perturbation. For example, an increase in surface air temperature could increase the evaporation; this in turn might increase the extent of cloud cover. Increased cloud cover would reduce the solar radiation reaching the Earth's surface, thereby lowering the surface temperature. This is an example of negative feedback and does not include the effects of longwave radiation or the advection in the oceans and the atmosphere, which must also be considered in the overall relationship of the climate system.@"0AM 4,0~climateclimate change- climate sensitivityThe magnitude of a climatic response to a perturbing influence. In mathematical modeling of the climate, the difference between simulations as a function of change in a given parameter. climate signalA statistically significant difference between the control and disturbed simulations of a climate model. See climate sensitivity. climate systemThe five physical components (atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere) that are responsible for the climate and its variations. climate variationDThe change in one or more climatic variables over a specified time. climatic analogpA past climate situation in which changes similar to the present occurred. Used in making climatic projections. climatic anomaly_The deviation of a particular climatic variable from the mean or normal over a specified time.climatic optimumw cloudA visible mass of condensed water vapor particles or ice suspended above the Earth's surface. Clouds may be classified on their visual appearance, height, or form. cloud albedoL cloud condensation nucleiaSmall particles of dust, smoke, or salt that serve as centers for condensation. Abbreviated CCN.cloud feedback cloud street0A st)raight or curved line of convective clouds. ClOxwCollective formula for the inorganic component of atmospheric chlorine, including ClO, ClONO2, HOCl, and OClO species. coalescenceqFusing together; the process by which a large raindrop grows larger by absorbing smaller drops in its fall path.BRotational flow of a fluid resulting from imbalances in density. This often occurs because the fluid below is heated and becomes less dense than the fluid above or because the fluid above is cooled and becomes more dense than the fluid below. Transfer of heat by physical movement of the heated medium from one place to another. Atmospheric or oceanic motions that are predominately vertical and that result in vertical transport and mixing of atmospheric or oceanic properties. Because the most striking meteorological features result if atmospheric convective motion occurs in conjunction with the rising current of air (i.e., updrafts), convection is sometimes used to imply only upward vertical motion.BThe quasi-horizontal flow of a fluid toward a common destination from different directions. When waters of different origins come together at a point or along a line (convergence line), the denser water from one side sinks under the lighter water from the other side. The ocean convergence lines are the polar, subtropical, tropical, and equatorial. Also see divergence. Movement of air on a plane toward a common point or common line (resulting in rising currents); the result of friction unbalancing the forces of geostrophic flow.AThe tendency for an object moving above the Earth to turn to the right in the Northern Hemisphere and to the left in the Southern Hemisphere relative to the Earth's surface. The effect arises because the Earth rotates and is not, therefore, an inertial reference frame.BThe portion of the climate system consisting of the world's ice masses and snow deposits, which includes the continental ice sheets, mountain glaciers, sea ice, surface snow cover, and lake and river ice. Changes in snow cover on the land surfaces are by and large seasonal and closely tied to the mechanics of atmospheric circulation. The glaciers and ice sheets are closely related to the global hydrologic cycle and to variations of sea level and change in volume and extent over periods ranging from from hundreds to millions of years.lACloud generally 10 or more kilometers tall, consisting of ice and water, appearing like towering, billowing cotton, generally with a white top (anvil) extending downstream from the cloud. Commonly called thunderstorm or thunderhead. Cloud turret can be white, gray, or very dark. Contains rain, supercooled water, graupel, ice crystals, and hail and is turbulent.AIn the same sense as the component of the earth's rotation about the local vertical (anticyclonic, the opposite). In the northern hemisphere a streamline curving to the left has cyclonic curvature, and wind speed decreasing to the left of the current represents cyclonic shear. Taken together, curvature and shear constitute the vorticity, or rotation of a body of air about the vertical axis.#G#1( *2(,$ coefficient of variationHStandard deviation of the annual flows divided by the mean annual flow. cold front_The boundary between a mass of warm air and a mass of cold air that underuns and displaces it. comma echoA thunderstorm radar echo which has a comma-like shape. It often appears during later stages in the life cycle of a bow echo.  conductionfTransfer of heat from one place to another by molecular agitation and without movement of the medium. contrailA streamer cloud of water drops or ice crystals that forms in the wake of an aircraft, resulting from condensation of moisture added to the air by the combustion of fuel. convection convective adjustmentA numerical procedure applied in many atmospheric models to approximate the vertical nonradiative heat transport. This procedure adjusts the lapse rate whenever necessary so that some prescribed critical lapse rate is never exceeded. convergenceCoriolis effect counter twilightA colored border of 6-12 in height above the eastern horizon a half hour before sunset showing transitions in orange, yellow, green, and blue. cryosphere  cumulonimbus!l cumulonimbus cloudA convective cloud characterized by strong vertical development in the form of mountains or huge towers topped at least partially by a smooth, flat, often fibrous anvil. Also known colloquially as a "thunderhead."  cumulusDetached clouds, generally dense and with sharp outlines, showing vertical development in the form of domes, mounds, or towers. Tops normally are rounded while bases are more horizontal. cycloneA large-scale system of winds blowing around a center of low pressure; motion is counterclockwise in the Nothern Hemisphere, clockwise in the Southern Hemisphere.cyclonic"&BThe dating of past events and variations in the environment and the climate by studying the annual growth rings of trees. The approximate age of a temperate forest tree can be determined by counting the annual growth rings in the lower part of the trunk. The width of these annual rings is indicative of the climatic conditions during the period of growth; wide annual rings signify favorable growing conditions, absence of diseases and pests, and favorable climatic conditions, while narrow rings indicate unfavorable growing conditions or climate.BThe progressive destruction or degradation of vegetative cover especially in arid or semiarid regions bordering existing deserts. Overgrazing of rangelands, large-scale cutting of forests and woodlands, drought, and burning of extensive areas all serve to destroy or degrade the land cover. The climatic impacts of this destruction include increased albedo leading to decreased precipitation, which in turn leads to less vegetative cover; increased atmospheric dust loading could lead to decreased monsoon rainfall and greater wind erosion and/or atmospheric pollution. Continuous and sustained human-induced decline toward desert-like conditions brought about by deforestation, overcultivation, and overgrazing. AA strong downdraft resulting in an outward burst of damaging winds on or near the ground. Downburst winds can produce damage similar to a strong tornado. Although usually associated with thunderstorms, downbursts can occur with showers too weak to produce thunder. lAThe process of accumulation and sinking of warm surface waters along a coastline. A change of air flow of the atmosphere can result in the sinking or downwelling of warm surface water. The resulting reduced nutrient supply near the surface affects ocean productivity and meteorological conditions of the coastal regions in the downwelling area. Compare upwelling.:H(4ʑ2u%&*)dendrochronology$& dendroclimatologyThe use of tree growth rings as proxy climate indicators. Tree rings record responses to a wider range of climatic variables over a larger part of the Earth than any other type of annually dated proxy record. density[The mass per unit volume of a substance, commonly expressed in grams per cubic centimeter. derecho(pronounced day-RAY-cho). A widespread and usually fast-moving windstorm associated with convection. Derechos can produce damaging straight-line winds over areas hundreds of miles long and more than 100 miles across. desertification% dew pointA measure of atmospheric moisture. It is the temperature to which air must be cooled in order to reach saturation (assuming air pressure and moisture content are constant).  dew pointQTemperature at which condensation begins on a surface; relative humidity is 100% diffusionMovement or spreading out of molecules, such as CO2 into a fluid or porous media, in such a way that concentrations tend to be equalized in all parts of the system. direct circulation^Circulation with rising warm and/or sinking cold air, converting potential to kinetic energy. dispersion (wave)ZThe spreading out of a wave train due to each wavelength traveling with its own velocity. dissociative recombinationNeutralization of a positive molecular ion by recombination with an electron to produce two neutral particles (atoms). These atoms may be in excited states. divergenceA horizontal flow of water, in different directions, from a common center or zone; it is often associated with upwelling. Also see convergence. Doppler radarRadar configured such that the phase of the transmitted signal can be compared to the received signal so that a frequency shift can be measured. This is used to compute the component of scatter motion in the direction toward or away from the radar. downburst&  downwelling'l dry depositionyInflux from the atmosphere of gaseous or particulate chemicals, occurring in the intervals between precipitation events.CA boundary separating moist and dry air masses, and an important factor in severe weather frequency in the Great Plains. It typically lies north-south across the central and southern high Plains states during the spring and early summer, where it separates moist air from the Gulf of Mexico (to the east) and dry desert air from the southwestern states (to the west). The dry line typically advances eastward during the afternoon and retreats westward at night. However, a strong storm system can sweep the dry line eastward into the Mississippi Valley, or ven further east, regardless of the time of day. A typical dry line passage results in a sharp drop in humidity (hence the name), clearing skies, and a wind shift from south or southeasterly to west or southwesterly. Severe and sometimes tornadic thunderstorms often develop along a dry line or in the moist air just to the east of it, especially when it begins moving eastward.AA quantitative method developed by H. H. Lamb for comparing the magnitude of volcanic eruptions. The formulae use observations either of the depletion of the solar beam, temperature lowering in the middle latitudes, or the quantity of solid matter dispersed as dust. The reference dust veil index is 1000, assigned to the Krakatoa 1883 eruption, and the index is calculated using all three methods, where the information is available, for statistical comparison purposes. Abbreviated D.V.I.kATemperature of a planet resulting from the balance between incoming solar radiation and outgoing planetary surface-emitted infrared radiation; does not include the temperature enhancement due to absorption and reemission due to absorption and reemission of outgoing infrared radiation by greenhouse gases. The effective temperature of the earth is 253 K (-4 F).(DAn irregular variation in ocean current that from January to March flows off the west coast of South America, carrying warm, low-salinity, nutrient-poor water to the south. It does not usually extend farther than a few degrees south of the equator, but occasionally it does penetrate beyond 12 S, displacing the relatively cold Peru Current. The effects of this phenomenon are generally short-lived, and fishing is only slightly disrupted. Occasionally (in 1891, 1925, 1941, 1957-58, 1965, 1972-73, 1976, 1982-83), the effects are major and prolonged. Under these conditions, sea surface temperatures rise along the coast of Peru and in the equatorial eastern Pacific Ocean and may remain high for more than a year, having disastrous effects on marine life and fishing. Excessive rainfall and flooding occur in the normally dry coastal area of western tropical South America during these events. Some oceanographers and meteorologists consider only the major, prolonged events as El Nio phenomena rather than the annually occurring weaker and short-lived ones. CAn analytical technique to study the solar radiation incident on the Earth in which explicit calculations of atmospheric motions are omitted. In the zero-dimensional models, only the incoming and outgoing radiation is considered. The outgoing infrared radiation is a linear function of global mean surface air temperature, and the reflected solar radiation is dependent on the surface albedo. The albedo is a step function of the global mean surface air temperatures, and equilibrium temperatures are computed for a range of values of the solar constant. The one-dimensional models have surface air temperature as a function of latitude. At each latitude, a balance between incoming and outgoing radiation and horizontal transport of heat is computed. Abbreviated EBM.G.$2֑>" %> -dry line) dual-Doppler solutionMethod of deducing the three-dimensional winds within storms that requires at least two radars and an auxiliary relation. Usually, the requirement of continuity of air entering and leaving a volume is used. dust devilkA small whirlwind common in dry regions and made visible by the dust and debris picked up from the ground.dust veil index* Earth shadowEThe curved red-to-blue shadow seen in the east shortly after sunset. eccentricityMeasures how elliptical the earth-sun orbit is, with consequent effects on solar radiation received by the earth. If e is the eccentricity, then (1 + e)/(1 - e) is the ratio of the farthest and closest earth-sun distance. ecosystem_The interacting system of a biological community and its nonliving environmental surroundings. eddyA circular movement of water or air that is formed where currents pass obstructions or between two adjacent currents that are flowing counter to each other,effective temperature+kEl Nio,( emissionsvMaterials (gases, particles, vapors, chemical compounds, etc.) that come out of smokestacks, chimneys, and tailpipes. emissivityThe ratio of the radiation emitted by a surface to that emitted by a black body at the same temperature. Ability of an object to emit thermal radiation, ranging from 0 for a nonemitter (perfect reflector) to unity for a perfect emitter (nonreflector).energy balance models- environmentaThe sum of all external conditions affecting the life, development, and survival of an organism. equatorial anomalyStructure of the low-latitude ionosphere in which there are two electron density maxima, at about 15 magnetic dip latitude, rather than one maximum at the subsolar point. equivalentAbberivation for mole-equivalent, calculated as the molecular or atomic weight multiplied by the number of charges on the ion. Equivalent units are required for charge-balance calculations.AEarth's interacting envelopes: the hydrosphere (mostly the ocean), atmosphere, biosphere, reactive lithosphere (that part of the rocky crust within reach of the processes of weathering). The processes of deep seawater circulation at spreading ridges overlap with endogenic (within the earth) processes. Also relevant are extraterrestrial processes. Refractory problems such as mass extinction usually become arenas for competing theories drawn from the three sources.ATheory proposed by James Lovelock and Lynn Margulis according to which the biosphere and atmosphere are considered as a unified living entity, in a lifelike homeostatic equilibrium state, where feedback mechanisms correct all changes in the existing conditions.BHydrodynamic models of the atmosphere on a grid or spectral resolution that determine the surface pressure and the vertical distributions of velocity, temperature, density, and water vapor as functions of time from the mass conservation and hydrostatic laws, the first law of thermodynamics, Newton's second law of motion, the equation of state, and the conservation law for water vapor. Abbreviated GCM. Atmospheric general circulation models are abbreviated AGCM, while oceanic general circulation models are abbreviated OGCM.@22Y}=*H5A eustatic sea level variationsgChanges in sea level that is a consequence of a change in the volume of the water in the global ocean. evapotranspirationDischarge of water from the Earth's surface to the atmosphere by evaporation from bodies of water, or other surfaces, and by transpiration from plants.exogenic system/ falloutSettling and deposition of particulate matter, such as tephra and volcanic aerosols, out of an eruption plume and onto the earth's surface. feedback mechanismsA sequence of interactions in which the final interaction influences the original one. Also see positive feedback and negative feedback. fogcLiquid particles less than 40 microns in diameter that are formed by condensation of vapor in air. fossil fuelhAny hydrocarbon deposit that can be burned for heat or power, such as petroleum, coal, and natural gas. frontZone of sharp temperature contrasts between cold and warm air masses. Fronts slope toward cold air (with slopes of order 1:100) and are associated with marked cyclonic wind shear and vertical shear. frontogenesisZThe process of producing large horizontal contrasts, principally in pressure and density. Gaia theory0general circulation models1 geophysical noiseFluctuations in a geophysical parameter that are of a quasirandom nature and cannot be attributed to fluctuations in known causative phenomena. geosphereThe solid mass (lithosphere) of the Earth as distinct from the atmosphere and hydrosphere or all three of these layers combined. geostrophic flow\A type of movement where the Coriolis force balances exactly the horizontal pressure force. glacial maximum~The position or time of the greatest advance of a glacier (e.g., the greatest equatorward advance of Pleistocene glaciation). glacial reboundThe isostatic adjustment of previously glaciated areas after glacial retreat (e.g., the uplift of Scandinavia after the most recent glaciation.BA mass of land ice that is formed by the cumulative recrystallization of firn. A glacier flows slowly (at present or in the past) from an accumulation area to an ablation area. Some well-known glaciers are: the Zermatt, Stechelberg, Grinelwald, Trient, Les Diablerets, and Rhone in Switzerland; the Nigards, Gaupne, Fanarak, Lom, and Bover in Norway; the Wright, Taylor, and Wilson Piedmont glaciers in Antarctica; the Bossons Glacier in France; the Emmons and Nisqually glaciers on Mt. Ranier, Wasington; Grinnell glacier in Glacier National Park, Montana; the Dinwood glacier in the Wind River Mountains and the Teton glacier in Teton National Park, both in Wyoming; and many glaciers in the Canadian Rockies.KAA type of precipitation consisting of frozen cloud droplets that have clumped and formed pellets. Snow pellets, i.e., white, opaque, approximately round ice particles having a snowlike structure and 2-5 mm in diameter. Precipitation particles composed of ice and formed by the accretion and freezing of supercooled water droplets.CA popular term used to describe the warming of the earth due to atmospheric constituents trapping the warmth radiated by the surface. The atmosphere of the earth keeps the surface about 30 C warmer than it would by without the atmosphere. Earth's surface is heated by absorbing the radiation of wavelengths 0.4-4 microns arriving from the sun through the atmosphere. In turn, it emits thermal infrared radiation of relatively higher wavelengths of 4-100 microns, to acheive a steady state. Due to the presence of an atmosphere with radiatively active trace gases like water vapor, carbon dioxide, methane, nitrous oxide, ozone, and halocarbons, which have absorption bands in the wavelength region of the earth's thermal emission, a good part of which is trapped. This trapping of the earth's thermal radiation by the atmospheric trace gases, and the consequent heating of its surface and surrounding, is commonly known as the greenhouse effect.6BTemperature enhancement due solely to the change in the atmospheric constituent of interest; also called trace-gas radiative forcing. Does not take into account various climate feedbacks, such as the greenhouse temperature enhancement associated with increased atmospheric water vapor in a warmer atmosphere. The water vapor feedback increases the greenhouse temperature forcing for a doubling of carbon dioxide by roughly 50-100% depending on the model; other feedbacks, including lapse rate feedback, increase the greenhouse temperature forcing by more than 100%.BThose gases, such as water vapor, carbon dioxide, tropospheric ozone, nitrous oxide, and methane, that are transparent to solar radiation but opaque to longwave radiation, particularly between 8-18 microns. Also see greenhouse effect and trace gas. Atmospheric gases that have the property of absorbing and then reemitting outgoing infrared or heat radiation emitted by the surface. Important atmospheric greenhouse gases are water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and chlorofluorocarbons (CFCs).AUseful polarized concepts of the state of the planet. "Greenhouse" collects together global warmth, flattened thermal gradients, increased humidity, low relief, high sea level, and reduced vigor of oceanic circulation with a tendency toward enhanced anoxia in some parts of the ocean. "Icehouse" is essentially the reverse state in that assemblage of generalizations. It is important to add not-so-icecap-prone and icecap-prone, respectively, without implying necessarily that the world was ever ice-free.=AMajor circular flow patterns in the oceans. The wind-driven eastward- and westward-flowing equatorial currents are blocked by the continents and rotate slowly in a clockwise direction in the North Atlantic and Pacific Oceans and in a counterclockwise direction in the South Atlantic, South Pacific, and Indian Ocean.AA direct thermally-driven and zonally symmetric large-scale atmospheric circulation first proposed by George Hadley in 1735 as an explanation for the trade winds. It carries momentum, sensible heat, and potential heat from the tropics to the midlatitudes (30). The poleward transport aloft is complemented by subsidence in the subtropical high-pressure ridge and a surface return flow. The variability of this cell and the Walker cell is hypothesized to be a major factor in short-term climatic change.D;"R"684@*glacier3 glacier flow (ice flow)MThe slow downward or outward movement of ice in a glacier caused by gravity. global energy budgetRBalance of radiative and convective fluxes within the atmosphere and the surface. glory!A colored halo opposite the sun.graupel4Kgreenhouse effect5greenhouse forcing66greenhouse gases7greenhouse or icehouse8 grounding lineThe boundary between the area where an ice shelf or a glacier is floating on water and where it is in contact with the shore or underlying earth ("grounded"). Gulf Stream meanderA transient winding bend in the Gulf Stream. These bends intensify as the Gulf Stream merges into the North Atlantic and can break up into detached eddies at about 40 N.gyre9= Hadley cell: hailRoundish ice mass consisting of concentric layers of ice formed on a mineral nucleus; hard, may be lumpy; diameters of 5 cm or more, though most of the hail measured at the earth's surface is less than 0.5 cm in diamter. half-lifeOTime after which half of the radioactive atoms initially present have decayed. haloqA colored ring, appearing 22 or 46 around the sun or moon, caused by refraction of light through ice crystals.AA radar reflectivity pattern characterized by a hook-shaped extension of a thunderstorm echo, usually in the right-rear part of the storm (relative to its direction of motion). A hook often is associated with a mesocyclone, and indicates favorable conditions for tornado development. AThe process of evaporation, vertical and horizontal transport of vapor, condensation, precipitation, and the flow of water from continents to oceans. It is a major factor in determining climate through its influence on surface vegetation, the clouds, snow and ice, and soil moisture. The hydrologic cycle is responsible for 25 to 30 percent of the mid-latitudes' heat transport from the equatorial to polar regions.AIn the vector equation of motion, the form assumed by the vertical component when all Coriolis, earth-curvature, frictional, and vertical-acceleration terms are considered negligible compared with those involving the vertical pressure force and the force of gravity. The error in applying the hydrostatic equation to the atmosphere for cyclonic-scale motions is less than 0.01%. In extreme situations, the strong vertical accelerations in thunderstorms and mountain waves can be 1% of gravity.F? }@&4< halonsCompounds containing only carbon, bromine, and one or more other halogens (chlorine, fluorine). Completely halogenated hydrocarbons with at least one bromine atom, usually having long lifetimes and mostly used as fire retardants. heat flux (thermal flux)MThe amount of heat that is transferred across a unit area in a unit of time. heat island effectmA "dome" of elevated temperatures over an urban area caused by the heat absorbed by structures and pavement. heat sinkAThat portion of a thermodynamic system that absorbs unused heat. hertzPThe unit of frequency equal to one cycle per second or 2 pi radians per second. heterogeneous chemistryChemical transformations involving reactants (including catalytic agents) in different phases. For example, ClNO3 + HCl(solid) ---> Cl2 + HNO3(solid) or ClNO3 + H20(solid) ---> HOCl + HNO3(solid). HFHigh frequency (~3-30 MHz) Holocene^The most recent epoch of the Quaternary period, covering approximately the last 10,000 years. hook echo< hurricaneA violent tropical cyclone storm of the western Atlantic. A tropical storm with pronounced rotary circulation, constant wind speed of 74 miles per hour (64 knots) or more. hydrologic budget`A quantitative accounting of all water volumes and their changes with time for a basin or area.hydrologic cycle= hydrometeor4Any form of precipitation (snow, rain, hail, etc.). hydromiteKAn ice cylinder, like a cave stalagmite, formed by falling drops of water. hydrosphereThe aqueous envelope of the Earth, including the oceans, freshwater lakes, rivers, saline lakes and inland seas, soil moisture and vadose water, groundwaters, and atmospheric vapor.hydrostatic equation>AThe reflectivity of ice and snow-covered surfaces. The albedo of freshly fallen snow may be as much as 90%, while older snow may have values of 75% or less. The larger the areal extent of snow and ice cover, the higher the albedo value. The surface albedo will also increase as a function of the depth of snow cover up to 13 cm and be unaffected by increased snow cover after reaching that depth.BInteractions that can be described as a theoretical concept of a feedback mechanism in which the interacting elements are the areal extent of polar ice and snow cover, the albedo of the polar region (dependent on areal extent of ice and snow), absorption of solar radiation (dependent on the albedo), temperature (dependent on the absorption of solar radiation), and the area of ice and snow cover (dependent on temperature). Less snowfall would mean more absorption of solar radiation, therefore a surface warming would occur. Climate modeling studies indicate an amplification effect (i.e., positive feedback) of the ice and snow albedo feedback on increased surface air temperatures caused by increases in the atmospheric concentrations of carbon dioxide.AA glacier of considerable thickness and more than 50,000 sq. km in area. It forms a continuous cover of ice and snow over a land surface. An ice sheet is not confined by the underlying topography but spreads outward in all direction. During the Pleistocene Epoch, ice sheets covered large parts of North America and northern Europe but they are now confined to polar regions (e.g., Greenland and Antarctica). Also called continental glacier.;BA sheet of very thick ice with a level or gently undulating surface. It is attached to the land on one side, but most of it is floating. On the seaward side, it is bounded by a steep cliff (ice front) two to 50 m or more above sea level. Ice shelves have formed along polar coasts (e.g., Antarctica and Greenland); they are very wide, with some extending several hundreds of kilometers toward the sea from the coastline. They increase in size from annual snow accumulation and seaward extension of land glaciers. They decrease in size from warming, melting, and calving.AElectromagnetic radiation emitted by the sun that is incident on the earth's upper atmosphere. Most of the incoming solar radiation is in the spectral region 0.3-5 microns. The earth's atmosphere is largely transparent to the incoming solar radiation and permits most of it to reach the surface (the rest is reflected back to space by clouds and the surface). At the surface, the incoming solar radiation is absorbed and heats the surface.YBElectromagnetic radiation lying in the wavelength interval from 0.7 microns to 1000 microns. Its lower limit is bounded by visible radiation, and its upper limit is bounded by microwave radiation. Most of the energy emitted by the Earth and its atmosphere is at infrared wavelengths. Infrared radiation is generated almost entirely by large-scale intramolecular processes. The tri-atomic gases, such as water vapor, carbon dioxide, and ozone absorb infrared radiation and play important roles in the propagation of infrared radiation in the atmosphere. Abbreviated IR; also called longwave radiation.;GF:du&&yD8 hygroscopic9Absorbing or attracting moisture, as with salt crystals. ice ageA glacial epoch or time of extensive glacial activity. Also, as Ice Age, which refers to the latest glacial epoch, the Pleistocene Epoch. Periods characterized by very low temperature worldwide and advancing glaciers.ice and snow albedo@(ice and snow albedo temperature feedbackA ice coreDeep drill into the earth's permanent glaciers revealing the history of the atmospheric gas and dust content, enabling deduction of former atmospheric temperatures. ice coverDuring the present time, the extent, especially the thickness, of glacier ice on a land surface. Also the same as ice concentration, which is the ratio of an area of sea ice to the total are of sea surface within some large geographic area. ice islandsTabular icebergs that have broken off the ice shelves of northern Ellesmere Island; can be up to 60 m thick and 30 km wide, drift with the pack ice, and have been known to last for as much as three decades. ice sheetB ice shelfC; ice streamsLarge, fast glaciers embedded in slow-moving ice. Flow velocities are a few hundred meters to kilometers per year. icebergA floating ice mass up to 100 km long and 200-300 M thick that has broken off (calved) from ice shelves, glaciers, or coastal ice cliffs into the ocean. incoherent scatter radarSensitive radar operating on a frequency well above the critical frequency that detects radio signals scattered from refractive index irregularities in the ionospheric and/or neutral atmosphere.incoming solar radiationD index of variabilityAStandard deviation of the annual flood series in the log domain. infrared emissionILight in the infrared region of the spectrum emitted by a heated sample.infrared radiationEYHAThe solar radiation incident on a unit horizontal surface at the top of the atmosphere; sometimes referred to as solar irradiance. The latitudinal variation of insolation supplies the energy for the general circulation of the atmosphere. Insolation depends on the angle of incidence of the solar beam and on the solar constant.AA layering of the atmosphere that tends toward vertical overturning. Property of a system such that certain distrubances or perturbations introduced into the steady state will increase in magnitude; tendency of an atmosphere to overturn, enhanced by some disturbance or perturbation; specifically when a parcel of air, being lifted, encounters ambient air cooler than itself and thereafter rises of its own accord.@A fast-moving ribbon of air that occurs near the top of the troposphere; width is 25-100 km, thickness 1-3 km, and velocity 99-300 km per hour. Strong zonal current of air, usually near the 500-mbar constant pressure surface in each hemisphere, that encircles the earth. Referred to as the jet stream because of its high concentration and great speed, often up to 500 km/h. Current of strongest wind (order 50 m/s) surmounting a region of stron\g tropospheric baroclinity and with pronounced decreases of wind toward its lateral flanks.GJ(*1n!y9Mx(9 infrared spectroscopyfInteraction of infrared radiation with a sample, usually to excite vibrational modes of the material. insolationGH instabilityHInternal energy in the form of heat released when a change of state occurs from gas to liquid or liquid to solid. Heat is required to bring about a change of state from solid to liquid or liquid to gas. inversionAn anomaly in the normal positive lapse rate; usually refers to a thermal inversion, in which temperature increases rather than decreases with height. ion1An atom or molecule that has an electric charge. ionosphereYIonized gas (plasma) that surrounds the earth from approximately 90 to 600 km in height. irradiance{The total radiant flux received on a unit area of a given real or imaginary surface. Also called the radiant flux density. isobarLine of constant barometric pressure, usually on a map at a given height. (An isobaric surface is a three-dimensional surface of constant pressure.) isopynicIA line on a chart that connects all points of equal or constant density. isostatic adjustmentThe process whereby lateral transport at the Earth's surface from erosion or deposition is compensated for by movements in a subcrustal layer to maintain equilibrium among units of varying masses and densities. Also called isostatic compensation. isostatic sea level changeChange in relative sea level associated with a local radial displacement of the surface of the solid earth as, for example, may occur elastically in the near field of an earthquake source or viscously in response to glacial loading or unloading. isotach2Line or surface on which velocities are constant. isothermMA line on a chart that connects all points of equal or constant temperature. jet streamI Joule heating~Heating in the ionosphere below ~140 km height due to the interaction of ionospheric currents and the ambient electric field..ASurface of the geomagnetic field given by the longitudinal drift of an L line along which trapped charged particles bounce between northern and southern hemisphere. The L value is a length, in units of earth radius, which reduces to the equatorial radius of a field line in the case of a dipole field.SDThe component of the Earth's surface comprising the rock, soil, and sediments. It is a relatively passive component of the climate system, and its physical characteristics are treated as fixed elements in the determination of climate. Semirigid upper platelike layer of the earth. Its thickness is near zero at oceanic ridge axes, but it increases with age to about 100 km. Oceanic lithosphere consists of a crustal layer ~5 km thick of basaltic composition underlain by mantle rocks. Continental lithosphere consists of a layer of crustal rock 30-60 km thick of low density and variable composition underlain by mantle rocks. Layer of greater strength than the underlying asthenosphere for deformationat geological rates. It includes the crust and part of the uppermost mantle and is of the order of 100 km in thickness beneath the continents. Earth's cool outer rigid layer, including the crust, separated from the earth's deeper layers by a relatively weak zone, the asthenosphere. The lithosphere is of negligible thickness at some ocean ridges and may be as thick as 200 km or more beneath continents.LAA cold period that lasted from about A.D. 1550 to about A.D. 1850 in Europe, North America, and Asia. This period was marked by rapid expansion of mountain glaciers, especially in the Alps, Norway, Ireland, and Alaska. There were three maxima, beginning about 1650, about 1770, and 1850, each separated by slight warming intervals.AThe radiation emitted in the spectral wavelength greater than 4 microns corresponding to the radiation emitted from the Earth and atmosphere. It is sometimes referred to as "terrestrial radiation" or "infrared radiation," although somewhat imprecisely. Compare shortwave radiation.VGO"z9 99*08i katabatic windstWinds produced when gravity pulls cold, dense air from, fort example, the Antarctic plateau downslope to the coast.L shellK. La NiarConditions that are complementary to El Nio -- cold surface waters off Peru and intense trades over the Pacific. laminar flow.Smooth, nonturbulent flow of a gas or liquid. lapse rateThe rapidity with which temperature decreases with altitude. The normal lapse rate is defined to be 3.6 F per 1000 ft, and the wet adiabatic lapse rate varies between 2 and 5 F per 1000 ft. latent heatrEnergy transferred from the earth's surface to the atmosphere through the evaporation and condensation processes. latent heat fluxEnergy associated with the exchange of water vapor between ocean and atmosphere; amount (or rate) of surface evaporation per unit area per unit time expressed in energy units. Le Chatlier's principletWhen an external force is applied to an equilibrium system, the system adjusts to minimize the effect of the force. lidarLight detection and ranging, a family of laser-based remote-sensing techniques which involve sending a powerful laser beam into the atmosphere and collecting and analyzing the backscattered signal. lightninguElectrical discharge in thunderstorms caused by the separation of electric charge of positive and negative polarity. limbdThe edge of a celestial body as it appears to an observer; the edge of the sun's disk, for example. lithosphereLSLittle Ice AgeML long-range transportUTransport of pollutants within a moving air mass for a distance greater than 100 km.longwave radiationN magnetosphereEntire plasma envelope that surrounds the earth as constrained by the earth's dipole magnetic field and the interaction of this envelope with the solar wind, and with the interplanetary magnetic field.AThe average height of the sea surface, based upon hourly observation of the tide height on the open coast or in adjacent water that have free access to the sea. In the United States, it is defined as the average height of the sea surface for all stages of the tide over a nineteen year period. Mean sea level, commonly abbreviated MSL and referred to simply as "sea level," serves as the reference surface for all altitudes in upper atmospheric studies.,AAn astronomical theory formulated by the Yugoslav mathematician Milutin Milankovitch that associates climate change with fluctuations in the seasonal and geographic distribution of insolation determined by periodic variation of the Earth's eccentricity and obliquity and the longitude of perihelion.AAn investigative technique that uses a mathematical or physical representation of a system or theory that accounts for all or some of its known properties. Models are often used to test the effects of changes of system components on the overall performance of the system.TDA name for seasonal winds, first applied to the winds over the Arabian Sea that blow for six months from the northeast and for six months from the southwest. The term has been extended to similar winds in other parts of the world (i.e., the prevailing west to northwest winds of summer in Europe have been called the "European monsoon"). The primary cause for these seasonal winds is the much greater annual variation of temperature over large land areas compared with neighboring ocean surfaces, causing an excess of pressure over the continents in winter and a deficit in summer, but other factors, such as topography of the land, also have an effect. The monsoons are strongest in the southern and eastern sides of Asia, but also occur along the coasts of tropical regions wherever the planetary circulation is not strong enough to inhibit them. Term originally coined by Arab mariners in reference to the seasonally shifting winds in the Indian Ocean. It has now come to denote climatic systems anywhere in which rainfall is markedly seasonal and in which the moisture comes mainly in the warm season. AAbsorbed minus emitted radiation. On a global average the earth's surface and atmosphere, respectively, absorb 170 W/m2 and 60 W/m2 solar radiation and emit 70 and 160 W/m2 as infrared radiation. Thus the net radiative gain of 100 W/m2 by the earth equals the loss by the atmosphere.zHU-0:$".= mammatus cloudsRounded, smooth, sack-like protrusions hanging from the underside of a cloud (usually a thunderstorm anvil). Mammatus clouds often accompany severe thunderstorms, but do not produce severe weather; they may accompany non-severe storms as well.  Maunder minimumThe period from 1654 to 1714 when it was believed that there were no sunspots. It is now thought that there were some sunspots during that time but fewer than those counted after 1800.mean sea levelP Mediterranean cllmateA climate characterized by dry summers and wet winters, often found along coasts lying about 40 from the equator. Much of California and much of the Mediterranean region of Europe have this kind of climate.Milankovitch theoryQ, mist`Liquid particles 40 to 500 microns in diameter that are formed by condensation of vapor in air. mixed-phase regionZone in the atmosphere that contains water substance in all three of its phases (vapot, liquid, and solid) and whose temperature is gerneally between -40C and 0 C. MMEDMass Median Equivalent aerodynamic Diameter; where the equivalent aerodynamic diameter of a particle is the diameter of a sphere of density 1 g cm-3 that has the same falling velocity.modelingRmonsoonST monsoonal circulationAtmospheric circulation induced by differential land-ocean heating. In summer, the flow is from the ocean to land; in winter it is from land to ocean, but with modification by the effects of the earth's rotation. negative feedback_An interaction that reduces or dampens the response of the system in which it is incorporated. net radiationT NEXRADNext Generation Doppler Radar, the network of approximately 144 10-cm.-wavelength radars that form a component of the National Weather Service's radar storm identification network. normal modes of vibrationsNatural resonances on the coupled periodic displacements of atoms in a material about their equilibrium positions. nucleationThe beginning of the process of droplet or ice-crystal formation; homogenous nucleation occurs when there is no foreign particle to act as a nucleus. AInteractions that are invoked to explain why certain phenomena, such as the Southern Oscillation, are attributable to changes in the ocean from a meteorological perspective and are attributable to changes in atmospheric conditions from an oceanographic perspective.AIn calculating the transfer of radiant energy, the mass of an absorbing or emitting material lying in a vertical column of unit cross-sectional area and extending between two specified levels. Also, the degree to which a cloud prevents light from passing through it; the optical thickness then depends on the physical constitution (crystals, drops, and/or droplets), the form, the concentration, and the vertical extent of the cloud.vBElectromagnetic radiation emitted by the earth's surface sue to heating by incoming solar radiation. Most of the outgoing infrared radiation is in the spectral region 4-80 microns. The earth's atmosphere is not transparent to this outgoing radiation as greenhouse gases absorb and reemit these wavelengths. The downward-directed component of the reemitted infrared radiation results in an additional heating of the earth's surface and raises the surface temperature from 235 K (-49 F), which is the "effective" temperature of the earth, to 288 K (59 F). This additional heating is called the greenhouse temperature enhancement.]DA molecule made up of three atoms of oxygen. In the stratosphere, it occurs naturally and it provides a protective layer shielding the Earth from ultraviolet radiation and subsequent harmful health effects on humans and the environment. In the troposphere, it is a chemical oxidant and major component of photochemical smog. Ozone has a characteristic, pungent odor familiar to most persons because ozone is formed when electrical apparatus produces sparks in air. Ozone is irritating to mucous membranes and toxic to human beings and lower animals. The U.S. Occupational Safety and Health Administration standards for industrial workers exposed to ozone on a daily basis limit ozone concentrations to 0.1 ppm on the average, with a maximum of 0.3 ppm for short exposures. Near the Earth's surface the concentration is usually 0.02-0.03 ppm in country air, and less in cities except when there is smog (when concentrations may reach 0.5 ppm or more for brief periods). Maximum concentration -- 5 x 10E12 per cm3, more than 1000 times the normal peak level at the surface -- occurs at an altitude of 19 mi (30 km).FZN-.J)R obliquityMeasures the tilt of the earth's axis of rotation with respect to the plane of the earth-sun orbit; provides the mid and high latitudes with seasons. occluded frontsA complex front that forms when a cold front overtakes a warm front and cuts off warm-sector air from the surface. ocean mixingProcesses that involve rates of advection, upwelling/downwelling, and eddy diffusion and that determine how rapidly excess atmospheric carbon dioxide can be taken up by the oceans.ocean-atmosphere interactionsV  opacityThe degree of obscuration of light; for example, a glass window has almost 0% opacity, whereas a concrete wall has 100% opacity. optical depthW order of magnitudeRTen times; thus, an increase of two orders of magnitude is 10 x 10, or 100 times. orographicrPertaining to mountain ranges; thus, a mountain or hill that causes air to rise over it is an orographic barrier.outgoing infrared radiationXvozoneY] ozone holeyExtraordinary springtime ozone destruction. A phenomenon occurring primarily over Antarctica and first reported in 1985. ozone layer]Layer in the stratosphere with high concentrations of ozone. Generally between 20 and 30 km. pack iceIce produced when the ocean freezes. This ice is broken into floes of various sizes and is compressed into pressure ridges by winds and ocean currents. Floes are separated from one another by open water leads and larger open water bodies called polynyas. parhelic circleA halo around the sun. parhelionBA bright spot on the 22 and 46 haloes, horizontal with the sun. particulate matteriVery small pieces of solid or liquid matter, such as particles of soot, dust, aerosols, fumes, or mists.AThe manufacture by plants of carbohydrates and oxygen from carbon dioxide and water in the presence of chlorophyll and sunlight as the energy source. Oxygen and water vapor are released in the process. Photosynthesis is dependent on favorable temperature and moisture conditions as well as on the atmospheric carbon dioxide concentration. Increased levels of carbon dioxide can increase net photosynthesis in many plants.DThe transition region between the turbulent surface layer and the normally nonturbulent free atmosphere. This region is about 1 km in thickness and is characterized by a well-developed mixing generated by frictional drag as the air masses move over the Earth's surface. This layer contains approximately 10% of the mass of the atmosphere. Also called the atmospheric boundary layer or frictional layer; in air pollution literature, it is also called the mixing height -- pollutants released near the surface are quickly mixed up to the top of the PBL. Abbreviated PBL. The PBL height varies over a wide range (several tens of meters to several kilometers), particularly over land surfaces, and exhibits strong diurnal variations. The PBL height over land reaches its maximum value of the order of 1 km (range 0.2-5 km) in the late afternoon and its minimum value of the order of 100 m (range 20-500 m) before midnight. The lowest 10% of the PBL is called the surface layer (abbrev. SL), and is the portion most directly influenced by the surface.@]a0ز5DЊ perihelionTime of the closest earth-sun approach (presently occurs in early January). Aphelion is the time of the farthest earth-sun approach (presently occurs in early July). pHJInverse measure of the hydrogen ion concentration. pH of pure water is 7. photochemical smogfAir pollution caused by chemical reactions among various substances and pollutants in the atmosphere. photodissociationLSplitting of a molecule into component parts due to absorption of a photon. photoelectronOElectron ejected from an atom or molecule through the photoionization process. photoexcitationExcitation of an electron into an energy level above the ground state configuration by absorption of a photon by an atom or molecule. photoionizationKRemoval of an electron from an atom or molecule by absorption of a photon. photolysis@Breakdown of chemical compounds through the action of sunlight.photosynthesis[ phytoplankton\That portion of the plankton community comprised of tiny plants (e.g., algae, and diatoms). pileusPA cloud formed in saturated air above a convective tower and separated from it. planetary albedoThe fraction (approximately 30%) of incident solar radiation that is reflected by the earth-atmosphere system and returned to space, mostly by backscatter from clouds in the atmosphere.planetary boundary layer\ planetary waves_Atmospheric waves with wavelengths the order of the radius of the earth (~6000 km) and larger. plankton]Passively floating or weakly motile aquatic plants (phytoplankton) and animals (zooplankton) plasma(.Q}Κ6JDpolar stratospheric clouds^ polarized light'Light that vibrates only in one plane. positive feedbackVAn interaction that amplifies the response of the system in which it is incorporated.potential temperature_ precession`0 precipitationa pressure gradientThe rate of decrease in atmospheric pressure per unit of horizontal distance; used to indicate relative pressures on the earth's surface, and measured in the direction of most rapid decrease. profilerMultibeam fixed-antenna Doppler radar that points nearly vertically and measures the wind up to at least 15 km height. Operates from 900 to 50 MHz. propagating modesSWavelike motions that transport energy away from the excitation or source region. quantum yield=Efficiency of conversion of light energy to chemical energy.radarb&radiation balancecN radiative equilibriumhBalance of the absorbed solar flux and emitted terrestrial infrared flux of a planet viewed from space. radiative transferqTransfer of electromagnetic radiation in planetary atmospheres by means of scattering, absorption, and emission.radiative-convective modelsd)radiatively active gaseseAA balloon-borne instrument for the simultaneous measurement and transmission of meteorological data up to a height of approximately 30,000 m (100,000 ft). The height of each pressure level of the observation is computed from data received via radio signals.BLight detection and ranging technique, based on the Raman effect. The characteristic vibrational or rotational Raman lines of gas-phase molecules in the atmosphere are monitored to provide a three-dimensional map of their concentration profiles. Rotational Raman lines of O2 and N2 molecules give a useful measure of the atmospheric temperature profile. Vibrational Raman lidar is particularly useful for monitoring SO2, CO2, and water vapor, and can be used to measure the concentration and spatial distribution in volcanic plumes._ATropical regions situated between 20 N and 20 S exhibit two main ecosystems, the rain forest and the savannah; the boreal regions, primarily located between 55 and 65 are mostly covered by the taige (conifer forest); the temperate regions between 40 and 55 display the most perturbed ecosystems (fields and various conifer and deciduous trees).AA low, horizontal tube-shaped arcus cloud associated with a thunderstorm gust front (or sometimes with a cold front). Roll clouds are relatively rare; they are completely detached from the thunderstorm base or other cloud features, thus differentiating them from the more familiar shelf clouds. Roll clouds usually appear to be "rolling" about a horizontal axis, but should not be confused with funnel clouds. Fk(*-FQց( radiometer_Instrument that measures visible, infrared, or microwave radiation at one or more frequencies. radiosondeg Raman lidarh Raman scatteringnScattering of visible light accompanied by a shift in wavelength due to interaction with molecular vibration. Raman spectroscopyZAnalysis of Raman scattered light to give information on vibrational modes of the sample. reflectivity|The ratio of the energy carried by a wave that is reflected from a surface to the energy of a wave incident on the surface. refractionGWave bending due to the spatial variation of wave speed in the medium.regions or latitude bandsi_ relative humidityThe amount of water in the air, expressed as a percentage of the maximum amount that the air could hold at a given temperature. reservoirXAny natural or artificial holding area used to store, regulate, or control a substance. reservoir speciesTrace constituent in the stratosphere that is unreactive toward ozone but that can be chemically converted to molecules that are catalytically active toward ozone. ridgeLine or wall of broken ice forced upward by pressure. The submerged volume of broken ice under a ridge, forced downward by pressure, is termed an ice keel. rimingbProcess of freezing of supercooled water droplets when they come into contact with ice particles. rocketsondeA rocket-borne instrument for measurement and transmission of upper-air meteorological data in the lower 76,000 m (250,000) ft) of the atmosphere, especially that portion inaccessible to radiosonde techniques. roll cloudj rollsKOrganized helical large eddies intrinsic to planetary boundary layer flow.ASmall, ragged, low cloud fragments (they are also called fractus) that are unattached to a larger cloud base and often seen with and behind cold fronts and thunderstorm gust fronts. Such clouds generally are associated with cool moist air, such as thunderstorm outflow. ,AThe change in a set of meteorological parameters averaged over three months. Seasonal variation is the largest climatic variation, and temperature is the most frequently observed meteorological parameter. Often, monthly averaged data are grouped into seasons, according to the prescribed definition.\AClimate or region where the precipitation is sufficient to support steppe, scrub, or dry savanna vegetation types. Variously characterized as receiving a mean annual precipitation between 300-400 and 700 or even 800 mm in summer rainfall areas and between 200-250 and 450-500 mm in winter rainfall regimes, at Mediterranean and tropical latitudes.AA low, horizontal wedge-shaped arcus cloud, associated with a thunderstorm gust front (or occasionally with a cold front, even in the absence of thunderstorms). Unlike the roll cloud, the shelf cloud is attached to the base of the parent cloud above it (usually a thunderstorm). Rising cloud motion often can be seen in the leading (outer) part of the shelf cloud, while the underside often appears turbulent, boiling, and wind-torn. Fp8$5*i roughness length]Length scale associated with the sea state; a measure of the efficiency of air-sea coupling. runoff ratiowProportion of precipitation which becomes runoff, usually calculated on an annual basis and expressed as a percentage. saturationA condition in the atmsophere corresponding to 100% relative humidity; super saturation is a condition corresponding to greater than 100% relative humidity. saturation vapor pressurePressure exerted by molecules of vapor (waper) when air is saturated and in equilibrium with respect to water or ice. Saturated vapor pressure is slightly, but significantly, greater when measured over water than over ice. Schaefer pointhThe temperature of -40 C (-40 F) at which ice crystals form spontaneously without the need of nuclei.scudl sea surface temperature\The temperature of the layer of seawater (approximately 0.5 m deep) nearest the atmosphere. seasonal runoff regime6Distribution of flow in a stream throughout the year.seasonal variationm,semiaridn\ sensible heatThe excess radiative energy that has passed from the Earth's surface to the atmosphere through advection, conduction, and convection processes. sensible heat fluxfThermal energy (enthalpy) per unit area per unit time that is exchanged between ocean and atmosphere. sfericsNatural atmospheric fluctuations of the electromagnetic fields, caused mainly by thunderstorm activity, in the range of 1-10E5 Hz. shelf cloudo shock waveXMoving wave of strong compression that usually travels faster than sound in the medium. shortwave radiationThe radiation received from the sun and emitted in the spectral wavelengths less than 4 microns. It is also called solar radiation.7BA quantitative measure of the statistical detectability of a signal, expressed as a ratio of the magnitude of the signal relative to the variability. For first detection of a CO2-induced climate change, the model signal is the mean change or anomaly in some climatic variable, usually surface air temperatures, attributed by a numerical model to increased concentrations of carbon dioxide. Observed noise is the standards deviation or natural variability computed from observations of that variable and adjusted for sample size, autocorrelation, and time averaging.AThe rate at which solar energy is received just outside the Earth's atmosphere on a surface that is normal to the incident radiation and at the mean distance of the Earth from the Sun. The current value is 0.140 watt/cm2. See also irradiance. Flux of incoming solar radiation incident at the top of Earth's atmosphere. The solar constant is about 1.4 x 10E6 erg/cm2/s or about 1367 W/m2.BA large-scale atmospheric and hydrospheric fluctuation centered in the equatorial Pacific Ocean. It exhibits a nearly annual pressure anomaly, alternately high over the Indian Ocean and high over the South Pacific. Its period is slightly variable, averaging 2.33 years. This variation in pressure is accompanied by variations in wind strengths, ocean currents, sea surface temperatures, and precipitation in the surrounding areas. El Nio occurrences are associated with the phenomenon. Irregular interannual fluctuation between El Nio and La Nia conditions that in the atmosphere has a scale larger than the tropical Pacific and extends into the Indian Ocean.'ALow-level clouds, existing in a relatively flat layer but having individual elements. Elements often are arranged in rows, bands, or waves. Stratocumulus often reveals the depth of the moist air at low levels, while the speed of the cloud elements can reveal the strength of the low-level jet. BThe region of the upper atmosphere extending from the tropopause (8 to 15 km altitude) to about 50 km. The thermal structure is determined by its radiation balance and is generally very stable with low humidity. Region of the earth's atmosphere from about 15 to 50 km above the surface. The stratosphere contains only about 15% of the total mass of the atmosphere but about 90% of the total amount of ozone in the atmosphere. Stratospheric ozone absorbs biologically lethal solar ultraviolet radiation (200-300 nm) and shields the surface.AA low, generally gray cloud layer with a fairly uniform base. Stratus may appear in the form of ragged patches, but otherwise does not exhibit individual cloud elements as do cumulus and stratocumulus clouds. Fog usually is a surface-based form of stratus. @w>^0<%.,"signal-to-noise ratioq7 smog(Air pollution associated with oxidants. smokeEParticles suspended in air after incomplete combustion of materials. soft modeMolecular vibrational mode for which the atomic displacements track the structural changes followed during a displacive phase transition. The frequency of the soft mode goes to zero at the transition temperature or pressure.solar constantr solar cycleyThe periodic change in sunspot numbers. It is the interval between successive minima and is about 11.1 years on average. solar windoEnergetic plasma and embedded magnetic fields thrown out from the sun affecting all parts of the solar system.Southern Oscillations squall line{A line along which converging air currents bring about cumulonimbus activity, with resulting heavy, squally precipitation. standing wave cloudA cloud formed at the crest of a wave in the airstream caused by a mountain peak or ridge. Wind blows through the cloud while the cloud remains stationary. steric sea level changeEustatic sea level change associated with a change in the volume occupied by fixed water mass caused by change in temperature or salinity. stratocumulust' stratosphereu stratospheric warmingDisturbance of the winter polar, middle atmosphere lasting for several days and characterized by a warming of the stratosphere (13-50 km altitude) by some tens of degrees.stratusv sublimationThe conversion of ice directly from solid to vapor, or from vapor to solid. (For the latter purpose, this term is being supplanted by the term ice condensation).BA relatively dark, sharply defined region on the solar disk, marked by an umbra approximately 2000K cooler than the effective photospheric temperature, surrounded by a less dark but also sharply bounded penumbra. The average spot diameter is about 3700 km, but can range up to 245,000 km. Most sunspots are found in groups of two or more, but they can occur singly. Sunspots are cyclic, with a period of approximately 11 years. The quantitative description of sunspot activity is called the Wolf sunspot number, denoted, R. The Wolf sunspot number is also referred to as Wolfer sunspot number, Zurich relative sunspot number, or relative sunspot number.{AThe temperature of the air near the surface of the Earth, usually determined by a thermometer in an instrument shelter about 2 m above the ground. The true daily mean, obtained from a thermograph, is approximated by the mean of 24 hourly readings and may differ by 1.0 C from the average based on minimum and maximum readings. The global average surface air temperature is 15 C.AThe fraction of solar radiation incident on the Earth's surface that is reflected by it. Reflectivity varies with ground cover, and during the winter months it varies greatly with the amount of snow cover (depth and areal extent). Roughness of terrain, moisture content, solar angle, and angular and spectral distribution of ground-based irradiations are other factors affecting surface albedo.AThe total infrared radiation emitted by the Earth and its atmosphere in the temperature range of ~200-300K. Because the Earth is nearly a perfect radiator, the radiation from its surface varies as the fourth power of the surface's absolute temperature. Terrestrial radiation provides a major part of the potential energy changes necessary to drive the atmospheric wind system and is responsible for maintaining the surface air temperatures within limits for habitability.BA minor constituent of the atmosphere. The most important trace gases contributing to the greenhouse effect are water vapor, carbon dioxide, ozone, methane, ammonia, nitric acid, nitrous oxide, ethylene, sulfur dioxide, nitric oxide, dichlorofuoromethane or CFC-12, trichlorofluoromethane or CFC-11, methyl chloride, carbon monoxide, and carbon tetrachloride. Atmospheric gases other than O2, N2, and CO2; their average volume mixing ratio is less than 1 ppmv. Any atmospheric constituent that is present in small amounts (less than 0.01%).AWinds that in each hemisphere blow diagonally westward toward the equator within about 30 latitude of the equator. They result from a zone of high pressure forming between about 20 and 30 from the equator, where air that has risen near the equator builds up.}CChemical elements (often radiative) or compounds that have finite lifetimes. Atmospheric testing of nuclear weapons from the mid-1950s to the early 1960s released large quantities of radionuclides to the to the atmosphere. Atmosphere-ocean exchange processes have transferred some of these elements to the oceans. Studying the behavior and distribution of these specific isotopes and other chemical tracers in the ocean will provide information on: residence time of the water and its dissolved components in gyres, basins, etc.; the mode and rate of formation and the subsequent spreading rates of specific water types, such as the polar water of the Norwegian and Greenland Seas; deep-ocean circulation and ocean-mixing processes, such as advection and upwelling; and the flux of anthropogenic carbgon dioxide into the ocean through its correlation with several different transient tracers.IE"B0q>&*6sunspotx supercooled cloudlCLoud in which the water droplets, though at temperatures below freezing, still remain in the liquid state. supernumerary bowsfAdditional bows inside the primary rainbow caused by diffraction effects in drops of different sizes. superoxide ion@A reduced form of dioxygen (O2-) that is an anion free radical.surface air temperaturey{surface albedoz terminal velocityThe maximum velocity at which a falling body moves through a medium, such as air. Pull of gravity balanced by friction resisting force.terrestrial radiation{ terrogenic effectsdStructures in the ionosphere attributable to the electrical (conductivity) structure of the ground. thermal wind relationTheoretical relationship in dynamical meteorology stating that the horizontal gradient in atmospheric temperature is proportional to the vertical gradient in horizontal wind. thermospherekRegion of the earth's upper atmosphere where temperature either remains constant or increases with height. tornadodA localized, violently destructive circular windstorm characterized by a long, funnel-shaped cloud. trace gas| trade winds}transient tracers~} transpirational water\Water that passes through the xylem cells through the stomata and raised pores of the leaf.RAThe boundary between the troposphere and the stratosphere (about 8 km in polar regions and about 15 km in tropical regions), usually characterized by an abrupt change of lapse rate. The regions above the troposphere have increased atmospheric stability than those below. The tropopause marks the vertical limit of most clouds and storms.CThe inner layer of the atmosphere below about 15 km, within which there is normally a steady decrease of temperature with increasing altitude. Nearly all clouds form and weather conditions manifest themselves within this region, and its thermal structure is caused primarily by the heating of the Earth's surface by solar radiation, followed by heat transfer by turbulent mixing and convection. Lowermost part of the atmosphere, dominated by turbulent movements providing a good mixing of the airborne constituents (its maximum height is ~ 12 km near the equator). Lowest region of the earth's atmosphere, extending from the surface to about 15 km above the surface. About 85% of the total mass of the stratosphere is found in the troposphere. The troposphere is the atmospheric region in which weather and clouds occur. Almost all of the water vapor in the atmosphere is in the troposphere. Hence, the troposphere is the most important atmospheric region from a climate perspective.IAWinds which shift in a clockwise direction with time at a given location (e.g., from southerly to westerly), or which change direction in a clockwise sense with height (e.g., southeasterly at the surface turning to southwesterly aloft). The latter example is a form of directional shear which is important for tornado formation.@F5 (*Ěrr. trapped modesKWavelike motions that remain trapped near the excitation or source region. trendTendency for sustained increases or decreases in concentrations. Sometimes the term is also applied to seasonal and cyclic behavior. tropical climateA climate in which the average annual temperature is in the range of 18 to 20C (64 to 68 F) or higher. Most tropical climates lie within about 30 of the equator. tropical depressionjA tropical disturbance with rotary circulation at surface, highest constant wind speed 38 mph (33 knots). tropical disturbanceA moving area of thunderstorms in the Tropics that maintains its identity for twenty-four hours or more. A common phenomenon in the tropics. tropical stormqA tropical depression with distinct rotary circulation, constant wind speed ranges from 39-73 mph (34-63 knots). tropopauseR troposphere turbidityV"Muddiness" in the atmosphere or ocean, cazused by large amounts of suspended matter. typhoonCA tropical cyclone of the western Pacific Ocean and the China Sea. undersunA mirrorlike image of the sun, reflected by high concentrations of floating ice crystals; appears at the same angle below the horizon as sun is above it. UV-A2Portion of the solar spectrum from 320 to 400 nm. UV-B2Portion of the solar spectrum from 280 to 320 nm. vapor`The gaseous phase of substances that are liquid or solid at atmospheric pressure (e.g., steam). veering windsI ventilationbRate (proportional to the surface wind speed) at which the sensible and latent heat fluxes occur.iAA zonal circulation of the atmosphere confined to equatorial regions and driven principally by the oceanic temperature gradient. In the Pacific, air flows westward from the colder, eastern area to the warm, western ocean, where it acquires warmth and moisture and subsequently rises. A return flow aloft and subsidence over the eastern ocean complete the cell.oBA localized, persistent, often abrupt lowering from a rain-free base. Wall clouds can range from a fraction of a mile up to nearly five miles in diameter, and normally are found on the south or southwest (inflow) side of the thunderstorm. When seen from within several miles, many wall clouds exhibit rapid upward motion and cyclonic rotation. However, not all wall clouds rotate. Rotating wall clouds usually develop before strong or violent tornadoes, by anywhere from a few minutes up to nearly an hour. Wall clouds should be monitored visually for signs of persistent, sustained rotation and/or rapid vertical motion. AWater present in the atmosphere in gaseous form; the source of all forms of condensation and precipitation. Water vapor, clouds, and carbon dioxide are the main atmospheric components in the exchange of terrestrial radiation in the troposphere, serving as a regulator of planetary temperatures via the greenhouse effect. Approximately 50 percent of the atmosphere's moisture lies within about 1.84 km of the earth's surface, and only a minute fraction of the total occurs above the tropopause.AA process in which an increase in the amount of water vapor increases the atmosphere's absorption of longwave radiation, thereby contributing to a warming of the atmosphere. Warming, in turn, may result in increased evaporation and an increase in the initial water vapor anomaly. This feedback, along with carbon dioxide, is responsible fro the greenhouse effect and operates virtually continuously in the atmosphere.2BIn general, a tornado occurring over water. Specifically, it normally refers to a small, relatively weak rotating column of air over water beneath a towering cumulus or cumulonimbus cloud. Waterspouts are most common over tropical or subtropical waters. The exact definition of waterspout is debatable. In most cases the term is reserved for small vortices over water that are not associated with storm-scale rotation. But there is sufficient justification for calling virtually any rotating column of air a waterspout if it is in contact with a water surface. F>*(*