Meteorology and atmospheric science terminology · MLC-0110

Meteorology and atmospheric science terms: C (1,012)

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Coastal climateThe distinctive weather patterns and atmospheric conditions experienced in regions adjacent to large bodies...
Coastal floodingFlooding which occurs when water is driven onto land from an adjacent body of water. This generally occurs...
Coastal frontA shallow, quasi-stationary atmospheric boundary that forms along a coastline, separating cold, dense air...
Coastal upwellingThe process where cold, nutrient-rich deep ocean water rises to the surface along a coastline. This...
Coastal watersIncludes the area from a line approximating the mean high water along the mainland or island as far out as...
Coastal Waters ForecastThe marine forecast for areas, including bays, harbors, and sounds, from a line approximating the mean high...
Coastal zoneThe transitional area where land meets the sea, encompassing both terrestrial and marine environments that...
Coastal Zone Color ScannerA satellite-borne instrument that was designed to measure ocean color, providing data on chlorophyll...
Coastal/Lakeshore Flood AdvisoryMinor flooding is possible (i.e., over and above normal high tide levels. Coastal/Lakeshore Flood Advisories...
Coastal/Lakeshore Flood WarningFlooding that will pose a serious threat to life and property is occurring, imminent or highly likely...
Coastal/Lakeshore Flood WatchFlooding with significant impacts is possible. Coastal/Lakeshore Flood Watches are issued using the...
Coastal/Lakeshore Flooding(i) (Oceanic) Coastal Flooding is the inundation of land areas caused by sea waters over and above normal...
Coastally trapped wavesOceanic waves that propagate along coastlines, with their energy confined to a narrow band near the shore...
Coaxial cableA type of electrical transmission line featuring a central conductor surrounded by an insulating layer, a...
Code formsStandardized alphanumeric sequences used for transmitting meteorological observations and forecasts...
COEIn hydrologic terms, Corps of Engineers.
Coefficient of barotropyThe proportionality factor B in the barotropy equation, in which the gradient of density equals B times the...
Coefficient of compressibilityA measure of a substance's relative volume change in response to a pressure change. It quantifies how much a...
Coefficient of correlationA statistical measure that quantifies the strength and direction of a linear relationship between two...
Coefficient of diffusionA proportionality constant that relates the flux of a substance due to diffusion to the concentration...
Coefficient of eddy viscosityA parameter representing the enhanced momentum transfer due to turbulent eddies in a fluid, analogous to...
Coefficient of mutual diffusionA parameter that quantifies the rate at which two different substances intermix due to random molecular...
Coefficient of thermal expansionA material property that quantifies how much a substance's size changes in response to a change in...
Coefficient of transparencyA measure of the fraction of incident radiation that passes through a medium without being absorbed or...
Coefficient of viscosityA measure of a fluid's resistance to shear flow, representing its internal friction. In meteorology, it...
Coffin cornerThe atmospheric flight regime at high altitudes where the stall speed and the maximum operating speed of an...
CoherenceA statistical measure of the correlation between two or more wave signals or time series as a function of...
Coherence timeThe duration over which a wave maintains a predictable phase relationship, or the time interval during which...
Coherent detectionA signal processing technique that involves mixing a received signal with a locally generated reference...
Coherent echoA radar signal return in which the phase relationship between the transmitted pulse and the received echo is...
Coherent integrationA radar signal processing step that adds successive pulse returns as complex samples with their phase...
Coherent radarA type of radar system that transmits pulses with a stable phase relationship and processes the received...
Coherent scatteringScattering in which the waves from many scatterers keep a definite phase relation to one another and to the...
Coherent structuresOrganized, recurring patterns of fluid motion within a turbulent flow that maintain their identity over a...
Coherent targetA radar target whose returns keep a definite phase relation to the transmitted wave from one pulse to the...
COHMAPA research collaboration, the Cooperative Holocene Mapping Project, that began in the 1970s to test...
ColA saddle point in a pressure field, representing a region between two high-pressure centers and two...
Co-latitudeThe angular distance of a point on a sphere from the North Pole, measured along a meridian. It is the...
Cold advectionTransport of cold air into a region by horizontal winds.
Cold air avalancheDownslope flow pulsations that occur at more or less regular intervals as cold air builds up on a peak or...
Cold air damA shallow cold air mass which is carried up the slope of a mountain barrier, but with insufficient strength...
Cold Air DammingThe phenomenon in which a low-level cold air mass is trapped topographically. Often, this cold air is...
Cold air funnelA funnel cloud or (rarely) a small, relatively weak tornado that can develop from a small shower or...
Cold capA high-latitude climatic zone in Supan's 1879 global classification where even the warmest month has a mean...
Cold conveyor beltA stream of cold, moist air that originates ahead of a warm front and flows westward beneath the warm...
Cold domeA shallow, lens-shaped body of cold air at the surface, formed when a stagnant air mass loses heat by...
Cold frontThe leading edge of an advancing mass of colder air, displacing warmer air. It is characterized by a sharp...
Cold highA high-pressure system whose core is colder than its surroundings, so that the surface pressure excess comes...
Cold lowA low-pressure system where the coldest air is found near the center of the circulation, extending through a...
Cold occlusionA frontal zone formed when a cold front overtakes a warm front and, being colder than the air ahead of the...
Cold poleThe geographical location on Earth that experiences the lowest average annual temperature or the lowest...
Cold poolA localized area of relatively cold, dense air that forms beneath a thunderstorm or convective system due to...
Cold sectorThe region of an extratropical cyclone occupied by the cold air mass, located behind the cold front and ahead...
Cold snapA rapid and pronounced decrease in air temperature over a relatively short period, often lasting for a few...
Cold soakProlonged exposure of equipment, an aircraft or other machinery to low ambient temperature until it cools to...
Cold tongueAn elongated region of relatively cold ocean water that extends into an area of warmer water, often...
Cold topA cool temperature perturbation in the upper troposphere and lower stratosphere of tropical convecting...
Cold troughAn elongated area of relatively low atmospheric pressure and cold air aloft, often extending equatorward from...
Cold type occlusionA type of occluded front where the air mass behind the cold front is colder than the air mass ahead of the...
Cold waveA rapid fall in air temperature, measured over 24 hours, to a level cold enough to require extra protection...
Cold weather advisoryThis product is issued for dangerously cold temperatures or wind chill values that are not expected to reach...
Cold-air injectionA push of cold air, identified in a cyclogenesis forecasting technique attributed to George, that appears on...
Cold-air poolA mass of cold, dense air that settles in a low-lying area, such as a valley or basin, under stable...
Cold-core ringsCyclonically rotating ocean eddies, roughly 100 to 300 km across, that pinch off from the Gulf Stream on its...
Cold-front thunderstormA type of thunderstorm that forms along or ahead of a cold front, where a mass of cold, dense air displaces...
Cold-front waveA wave-like disturbance that develops along a cold front, characterized by a bulge in the frontal boundary...
Collar cloudA rarely observed ring of cloud, roughly circular, that encircles the top of a wall cloud where the wall...
Collection efficiencyA measure of how effectively a cloud droplet or ice crystal captures smaller particles, such as other...
CollectorAn exposed sensor of an atmospheric electricity instrument that takes on the electrical potential of the...
Colligative propertyA property of a solution that depends solely on the number of solute particles dissolved in a given amount of...
Collision broadeningThe widening of spectral lines in atmospheric absorption or emission spectra due to collisions between...
Collision efficiencyThe probability that two cloud particles, after encountering each other due to their relative motion, will...
Collision theoryA theory explaining the growth of cloud droplets into raindrops through the process of collision and...
Collision-coalescence processThe primary mechanism for precipitation formation in warm clouds, where cloud droplets grow by colliding and...
Colloidal instabilityThe tendency of a colloidal system, such as a cloud, to lose its stability, leading to the growth and...
Colloidal suspensionA heterogeneous mixture where one substance, consisting of very fine particles, is dispersed uniformly...
Colloidal systemA mixture in which microscopic particles of one substance are evenly dispersed in another substance, forming...
Color look-up tableA mapping scheme that assigns specific colors to a range of data values, used to visualize meteorological...
Color temperatureThe temperature of an ideal blackbody whose light matches the color of a given source. A source with a...
Colorado lowA low-pressure system that forms or intensifies in the lee of the Rocky Mountains, specifically over the...
Colorado sunken panA buried evaporation pan, square and made of galvanised iron, used to estimate free-water evaporation...
Colored rainPrecipitation that appears discolored due to the presence of suspended particulate matter, such as dust...
ColorimetryThe scientific discipline concerned with the quantitative measurement and description of color perception. It...
ColumnA hypothetical vertical cylinder of air extending from the Earth's surface to a specified altitude or to the...
Column abundanceThe total number of molecules or mass of a specific atmospheric constituent integrated vertically through a...
Column modelA simplified atmospheric model that simulates vertical atmospheric processes at a single horizontal location...
Columnar iceIn hydrologic terms, ice consisting of columnar shaped grain. The ordinary black ice is usually...
Columnar resistanceThe electrical resistance of a vertical column of air of unit cross-section, found by integrating the...
Comb nephoscopeAn instrument used to determine the direction and speed of cloud movement by observing their passage relative...
COMBAR codeA synoptic code that combat aircraft use to report the weather elements they observe, written as groups of...
ComberA large wave whose crest is blown forward and breaks, in the usual sense a deep-water wave much bigger than a...
Combination coefficientA parameter that quantifies the rate at which small ions in the atmosphere attach to larger aerosol...
Combined seasGenerally referred to as SEAS. Used to describe the combination or interaction of wind waves and swells in...
Combustion nucleusA microscopic particle, often soot or other carbonaceous material, produced by the burning of organic matter...
Comfort chartA psychrometric chart or diagram that illustrates the range of atmospheric conditions (temperature, humidity...
Comfort curveA line or region on a psychrometric chart that delineates the combinations of temperature and humidity at...
Comfort zoneThe range of atmospheric conditions, primarily temperature and humidity, within which an average person feels...
Comma cloudA synoptic scale cloud pattern with a characteristic comma-like shape, often seen on satellite photographs...
Comma cloud systemA synoptic-scale weather system characterized by a cloud pattern resembling a comma, visible in satellite...
Comma echoA thunderstorm radar echo which has a comma-like shape. It often appears during latter stages in the life...
Comma headThe broad, rounded portion of a comma cloud system, located near the center of the associated low-pressure...
Comma tailThe elongated, narrower portion of a comma cloud system that extends from the comma head, typically trailing...
ComminutionThe process of reducing solid materials into smaller particles through mechanical action such as grinding...
Communication centerA facility responsible for the collection, processing, and dissemination of meteorological data and products...
CommutatorA rotating electrical switch made of insulated conducting segments that brushes contact in turn, reversing...
Compact differencingA class of numerical methods used in computational fluid dynamics, including atmospheric modeling, to...
CompactionThe process by which a material, such as snow or soil, becomes denser due to the rearrangement of its...
CompassAn instrument used for navigation and orientation that indicates direction relative to the Earth's magnetic...
Compensated scale barometerA mercury barometer with a fixed cistern whose scale divisions are shortened slightly to allow for the small...
Compensation of instrumentsThe design of an instrument, or the correction of its readings, so that a disturbing influence such as...
Competence of the windThe maximum size of a particle that wind can entrain and transport, either by rolling, saltation, or...
Complete freeze-upThe state of a water body, such as a lake or river, when its entire surface is covered by a continuous sheet...
Complex Gale/StormIn the high seas and offshore forecasts, an area for which gale/storm force winds are forecast or are...
Complex index of refractionA complex number whose real part sets the phase speed of electromagnetic waves in a medium relative to the...
Complex lowA large, multi-centered low-pressure system that develops when two or more individual low-pressure centers...
Complex refractive indexA complex number that describes the interaction of electromagnetic radiation with a medium, such as an...
Complex signalA mathematical representation of a wave or oscillation that uses complex numbers, comprising both a real and...
Complex terrainAn area characterized by irregular topography, including mountains, valleys, and hills, which strongly...
CompositeAn average that is calculated according to specific criteria. For example, one might want a composite for the...
Composite forecast chartA forecast chart for aviation drawn so that the weather shown at each point along a flight route is that...
Composite hydrographA stream discharge hydrograph which includes base flow, or one which corresponds to a net rain storm of...
Composite reflectivityA radar product that displays the maximum reflectivity value detected by a radar throughout the entire depth...
Composite vertical cross sectionA two-dimensional diagram showing the vertical structure of the atmosphere, created by averaging data from...
Composite water sampleA single water sample formed by combining multiple individual water samples collected at different times or...
Compound hydrographA graph of streamflow versus time that shows the effects of multiple, overlapping runoff events from separate...
Comprehensive Flare IndexIn solar-terrestrial terms, the indicative of solar flare importance.
CompressibilityThe measure of a fluid's or gas's relative volume change in response to a pressure change. In the atmosphere...
Compression waveA type of wave in which the oscillations of the medium's particles are parallel to the direction of wave...
Compressional waveA type of wave in which the oscillations of the medium's particles are parallel to the direction of wave...
Compton effectThe phenomenon where X-rays or gamma rays scatter off charged particles, typically electrons, resulting in a...
Computational modeAn artificial oscillation or instability that can arise in numerical models due to the discretization of...
ConcentrationThe amount of a substance present in a given volume or mass of air or other medium. It quantifies the...
Concentration basinAn ocean or sea basin in which evaporation exceeds the combined supply of precipitation and river runoff, so...
Concentration gradientThe spatial rate of change of the concentration of a substance, indicating how rapidly its amount varies from...
Concentration varianceA statistical measure of how much the concentration of a substance fluctuates about its mean at a point or...
Concentric eyewall cycleA process in intense tropical cyclones in which an outer eyewall forms around the original eye, contracts...
Concentric eyewallsTwo or more distinct, nearly circular bands of intense convection and strong winds that surround the center...
Concentric ringsThese are common in the most intense hurricanes. They usually mark the end the period of intensification...
Concrete minimum temperatureThe lowest temperature recorded at the surface of a concrete slab, which can differ from the air temperature...
CONDCondition
CondensationThe physical process by which water vapor in the atmosphere changes into liquid water. This phase transition...
Condensation funnelA funnel-shaped cloud associated with rotation and consisting of condensed water droplets (as opposed to...
Condensation levelThe altitude at which a parcel of unsaturated air, when lifted adiabatically, becomes saturated and...
Condensation nuclei counterAn instrument designed to detect and count the number of condensation nuclei (CN) present in a sample of air...
Condensation nucleusA particle, usually a soluble aerosol such as sea salt or sulfate, on which water vapor condenses into a...
Condensation pressureThe air pressure at the level where a parcel lifted dry-adiabatically first becomes saturated, which is the...
Condensation temperatureThe temperature at which air first becomes saturated with respect to liquid water. When air is cooled at...
Condensation trailA visible line of artificial cloud formed in the wake of an aircraft, consisting of ice crystals. These...
Conditional distributionA probability distribution that describes the likelihood of an event occurring given that another event has...
Conditional instabilityAn atmospheric state where a parcel of air is stable if unsaturated but becomes unstable if lifted to...
Conditional instability of the second kindA type of atmospheric instability that arises from a positive feedback loop between latent heat release from...
Conditional meanThe average value of a variable, calculated under the condition that another specific event or variable state...
Conditional probabilityThe likelihood of an event occurring, calculated under the assumption that one or more other events have...
Conditional samplingA measurement technique where data is collected or analyzed only when specific atmospheric conditions or...
Conditionally unstable airAn atmospheric condition that exists when the environmental lapse rate is less than the dry adiabatic lapse...
Conditions of readinessA set of predefined operational states or alert levels indicating the preparedness of personnel and equipment...
Conductance for moistureA measure of the ease with which water vapor can move through a material or across an interface, such as...
ConductionThe transfer of heat through a material by molecular collisions and vibrations, without bulk motion of the...
Conduction currentThe flow of electric charge through a medium due to the movement of free electrons or ions under the...
ConductivityA property of a medium that sets the flux of charge or heat per unit electric field or temperature gradient...
Conductivity-temperature-depth profilerAn oceanographic instrument, abbreviated as CTD, that measures the electrical conductivity, temperature, and...
Cone of depressionIn hydrologic terms, the depression, roughly conical in shape, produced in a water table, or other...
Cone of influenceSame as Cone of Depression; in hydrologic terms, the depression, roughly conical in shape, produced in a...
Cone of visionThe imaginary cone whose apex is at an observer's eye and whose solid angle is exactly filled by the object...
Confidence intervalAn interval computed from sample data such that, over repeated sampling, a stated share of such intervals...
Confined ground waterIn hydrologic terms, ground water held under an aquiclude or an aquifuge, called artesian if the pressure is...
Confined groundwaterAn accumulation of groundwater that is trapped between two relatively impermeable layers of rock or sediment...
ConfluenceA pattern of the wind field in which streamlines come closer together in the downstream direction, the...
Conformal mapA map projection that preserves angles locally, meaning that the shape of small features is accurately...
CongelifractionThe process of rock weathering caused by repeated cycles of freezing and thawing of water within cracks and...
CongeliturbationThe churning and mixing of soil and unconsolidated sediments due to repeated freezing and thawing cycles in...
CongestusA species of cumulus cloud characterized by its towering, cauliflower-like appearance and considerable...
Congressional Organic Act of 1890The act that assigned the responsibility of river and floor forecasting for the benefit of the general...
Conical beamA radio-frequency or microwave signal transmitted or received by an antenna in a cone-shaped pattern. This...
Conical scanningA radar scanning technique where the antenna rotates its beam in a circular path around a central axis...
ConingA phenomenon observed in smoke plumes from stacks, where the plume spreads out in a cone shape both...
Conjugate pointsTwo points on the earth's surface, at opposite ends of a geomagnetic field line
ConjunctionThe alignment of two celestial bodies at the same celestial longitude or right ascension as seen from Earth...
Connate waterWater that was trapped in the pore spaces of a sedimentary rock during its original deposition and has been...
Consecutive meanA moving average in which each value is the mean of a fixed number of successive data points, with the window...
Consensus averageThe mean wind value produced by consensus averaging of wind profiler measurements: the average of the largest...
Consensus averagingA statistical method used in wind profiler and Doppler radar processing to separate true atmospheric Doppler...
ConsequentA type of stream or river whose course is directly determined by the initial slope of the land surface. These...
Conservation of angular momentumA fundamental physical principle stating that the total angular momentum of a system remains constant if no...
Conservation of energyA fundamental physical principle stating that the total energy within an isolated system remains constant...
Conservation of massA fundamental principle stating that mass cannot be created or destroyed in an isolated system. In...
Conservation of momentumA fundamental physical law stating that the total momentum of a closed system remains constant in the absence...
Conservation of vorticityA principle stating that the absolute vorticity of an air parcel remains constant as it moves, provided there...
Conservation storageIn hydrologic terms, storage of water for later release for usual purposes such as municipal water supply...
ConservatismThe tendency of an air mass to keep its characteristic properties, such as temperature and humidity, as it...
Conservative fieldA vector field where the line integral between any two points is independent of the path taken, meaning the...
Conservative pollutantsAtmospheric pollutants that undergo minimal or no chemical transformation or removal processes during their...
Conservative propertyA characteristic of an air parcel or fluid that remains constant as the parcel moves, provided no external...
Conserved variable diagramA thermodynamic diagram that plots two or more conservative atmospheric variables against each other, such as...
Consistent numerical schemeA numerical method used in atmospheric models where the discretized equations converge to the original...
Consolidated iceSea ice at a concentration of 10/10 in which the floes are frozen together into a continuous cover, leaving...
Consolidated ice coverIn hydrologic terms, ice cover formed by the packing and freezing together of floes, brash ice and other...
ConsolidationThe process by which individual ice floes or fragments become frozen together to form a more continuous and...
ConstancyA wind statistic equal to the ratio of the magnitude of the vector mean wind to the mean wind speed averaged...
Constant absolute vorticity trajectoryThe path followed by an air parcel in the atmosphere where its absolute vorticity remains unchanged. This...
Constant flux layerThe portion of the atmospheric surface layer, extending from the ground up to about 10% of the boundary layer...
Constant-height chartA meteorological chart that displays atmospheric variables, such as pressure, temperature, or wind, at a...
Constant-height surfaceA horizontal surface at a fixed geometric height above a reference datum such as mean sea level, on which...
Constant-level balloonAn instrumented balloon designed to stay at a nearly fixed level in the atmosphere for a long period, so that...
Constant-pressure chartA meteorological chart that displays atmospheric variables, such as height, temperature, and wind, on a...
Constant-pressure surfaceAn imaginary surface in the atmosphere where the atmospheric pressure is uniform everywhere. These isobaric...
Constant-pressure-pattern flightA flight technique in which an aircraft holds a constant pressure altimeter setting and altitude, so it...
Constant-rate dilution gaugingA method for measuring water flow rate in a channel or stream by injecting a chemical or fluorescent tracer...
ConsultationThe process where a meteorologist provides expert advice, analysis, and interpretation of weather and climate...
Consumptive useThe portion of water withdrawn from a source that is not returned to the immediate water environment because...
CONTContinue/Continuously
Contact angleThe angle formed at the three-phase boundary where a liquid, gas, and solid intersect, measured within the...
Contact flightA type of visual flight where the pilot navigates primarily by reference to visible landmarks on the ground...
Contact nucleusA microscopic particle that initiates the freezing of supercooled water droplets upon direct contact. These...
Contact weatherAtmospheric conditions that permit flight under Visual Flight Rules (VFR), where pilots can navigate by...
ContaminantAny substance present in the atmosphere that is not naturally occurring or is present at concentrations above...
ContaminateTo introduce unwanted substances into the atmosphere, water, or soil, altering their natural composition or...
ContentsIn hydrologic terms, the volume of water in a reservoir. Unless otherwise indicated reservoir content is...
Contessa di ventoA stationary, lens-shaped or cap-like cloud that forms over the summit of Mount Etna in Sicily. This type of...
Continental aerosolAtmospheric particulate matter originating from land-based sources, including dust from arid regions, smoke...
Continental airAn air mass that originates over a large landmass, characterized by low moisture content and temperature...
Continental air massA dry air mass originating over a large land area. Contrast with tropical air mass.
Continental borderlandA region offshore of a continent characterized by complex and irregular seafloor topography, including a...
Continental climateA climate type characterized by large annual and diurnal temperature ranges, with relatively low...
Continental cloudA cloud formation that develops over landmasses, influenced by the thermal and moisture characteristics of...
Continental driftThe large-scale horizontal movement of continents across the Earth's surface over geological time, driven by...
Continental highA large, slow-moving area of high atmospheric pressure that forms over a continent, particularly during...
Continental platformAnother name for the continental shelf, the gently sloping submerged edge of a continent that extends from...
Continental shelfThe gently sloping, submerged area of a continent extending from the coastline to the steeper continental...
Continental shelf waveA type of ocean wave that propagates along the continental shelf, trapped by the bathymetry and the Coriolis...
Continental slopeThe steeply inclined zone of the seabed that extends from the outer edge of the continental shelf down to the...
ContinentalityThe degree to which a region's climate is influenced by its distance from large bodies of water, resulting in...
Continentality indexA numerical value that quantifies the degree to which a location's climate is influenced by its distance from...
Contingency tableA tabular display that summarizes the relationship between two or more categorical variables, often used in...
Continuing currentA sustained flow of electric charge that follows an initial lightning discharge, typically observed in...
ContinuityThe principle in fluid dynamics stating that mass is conserved within a moving fluid, meaning that fluid...
Continuous spectrumAn electromagnetic spectrum that contains all wavelengths within a given range, without any gaps or discrete...
Continuous-wave radarA type of radar system that transmits a continuous, uninterrupted radio wave rather than short pulses...
Continuum absorptionThe absorption of electromagnetic radiation by atmospheric gases over a broad range of wavelengths, rather...
Continuum StormIn solar-terrestrial terms, general term for solar noise lasting for hours and sometimes days.
ContourA line on a map or chart that connects points of equal value for a specific meteorological variable. These...
Contour chartA meteorological map that displays lines connecting points of equal value for a specific atmospheric...
Contour intervalThe fixed difference in value between neighbouring contour lines on a chart, such as 60 m between height...
Contour lineA line on a map joining points of equal value of a quantity, such as pressure, temperature or height. In...
Contour mapA graphical representation that uses contour lines to depict the spatial distribution of a particular...
Contour microclimateThe part of a site's microclimate that arises directly from small-scale irregularities in the ground surface...
Contra solemA Latin phrase meaning against the sun, coined by the oceanographer Ekman in 1923 for rotation opposite to...
Contraction coefficientA dimensionless ratio used in fluid dynamics to describe the narrowing of a fluid stream as it passes through...
ContrailA linear cloud formed in the wake of an aircraft, resulting from the condensation of water vapor emitted by...
Contrail-formation graphA graphical representation that illustrates the atmospheric conditions under which aircraft contrails are...
ContrastThe difference in radiative properties, such as brightness or temperature, between a meteorological feature...
Contrast stretchingAn image enhancement technique applied to satellite or radar data to increase the visual distinction between...
Contributing regionThe volume of atmosphere seen by a weather radar, set by the beam width and pulse length, whose scatterers...
Control areaA controlled airspace extending upward from a specified limit above the ground or water, established to...
Control pointsIn hydrologic terms, small monuments securely embedded in the surface of the dam. Any movement of the...
Control-tower visibilityThe horizontal distance at which an observer in an airport control tower can identify unlighted objects...
CONTScontinues
CONUSContinental United States
ConvectionThe transfer of heat or other atmospheric properties by the movement of fluid, specifically through the...
Convection cellA distinct region within a fluid where convective motions occur, characterized by rising warm fluid and...
Convection currentA localized flow of fluid, such as air or water, driven by differences in density caused by temperature...
Convection initiationThe initial stage in the development of a deep, moist convective storm, such as a thunderstorm. It marks the...
Convection theory of cyclonesA nineteenth-century hypothesis, associated chiefly with James Espy, that cyclonic storms are driven by...
Convection-allowing modelA numerical weather prediction model with a horizontal grid spacing fine enough to explicitly resolve...
Convective activityThe presence and intensity of atmospheric processes driven by buoyancy, primarily involving rising air...
Convective adjustmentA parameterization scheme used in numerical weather prediction models to represent the effects of unresolved...
Convective available potential energyA measure of the maximum possible kinetic energy that an air parcel can acquire if lifted adiabatically...
Convective boundary layerThe lowest part of the atmosphere, extending from the surface upward, characterized by vigorous vertical...
Convective cloudA cloud formed by the vertical transport of warm, moist air parcels that rise due to buoyancy, cool, and...
Convective clouds, see Convective cloud
Convective condensation levelThe level at which a parcel, heated from below until it rises dry-adiabatically on its own buoyancy, first...
Convective inhibitionA measure of the energy required to lift an air parcel from the surface to its level of free convection...
Convective instabilityA state of the atmosphere where a layer of air, while stable with respect to dry adiabatic ascent, becomes...
Convective mass fluxThe rate at which mass is transported vertically by convective processes within the atmosphere, typically...
Convective mixed layerA layer of the atmosphere, typically near the surface, where vigorous vertical mixing by convection leads to...
Convective outlook(sometimes called AC) - A forecast containing the area(s) of expected thunderstorm occurrence and expected...
Convective overdevelopmentConvection that covers the sky with clouds, thereby cutting off the sunshine that produces convection.
Convective overturnThe process by which an unstable layer of fluid, such as air, rapidly mixes vertically as warmer, less dense...
Convective plumeA column of buoyant fluid, such as warm air, rising vertically through a denser surrounding fluid. In the...
Convective precipitationPrecipitation that originates from convective clouds, such as cumulus and cumulonimbus, characterized by its...
Convective regionAn area within a larger weather system, such as a tropical cyclone or a squall line, where active convection...
Convective Richardson numberA dimensionless ratio of the buoyant energy available to a convective storm to the kinetic energy of the...
Convective showersPrecipitation of short duration and variable intensity that falls from a convective cloud, such as a cumulus...
Convective stormA weather phenomenon driven by the vertical transport of heat and moisture in the atmosphere, resulting in...
Convective temperatureThe surface temperature required for a parcel of air, when lifted adiabatically from the surface, to become...
Convective termA mathematical expression in a fluid dynamics equation that represents the transport of a property, such as...
Convective transportThe process by which heat, moisture, or other atmospheric properties are moved vertically or horizontally...
Convective transport theoryA theory of surface fluxes in a statically unstable boundary layer, proposed by Roland Stull in 1994, in...
Convective turbulenceIrregular, chaotic air motions generated by buoyancy forces arising from differential heating of the Earth's...
ConvergenceThe net inflow of air into a specific region of the atmosphere, resulting in an accumulation of mass. This...
Convergence bandA narrow zone in the atmosphere where air currents flow together, leading to upward vertical motion and often...
Convergence lineA narrow zone in the atmosphere where air currents flow together from different directions, causing air to...
Convergent numerical schemeA numerical method for solving differential equations where the numerical solution approaches the true...
Conversion factorA numerical ratio used to change a quantity expressed in one unit of measurement into an equivalent quantity...
Conveyance lossIn hydrologic terms, the loss of water from a conduit due to leakage, seepage, evaporation, or...
ConvolutionA mathematical operation that combines two functions to produce a third function, expressing how the shape of...
Cool changeThe abrupt arrival of a cooler air mass, marked by a sharp drop in temperature and a shift in wind direction...
Cooling Degree Days(Abbrev. CDD) - A form of Degree Day used to estimate energy requirements for air conditioning or...
Cooling powerA measure of the rate at which an object or organism loses heat to its surrounding environment, influenced by...
Cooling-power anemometerAn instrument that measures wind speed by sensing the rate of heat loss from a heated element exposed to the...
CoolometerA specialized instrument designed to measure the cooling power of the atmosphere, often by assessing the rate...
Cooperative observerA volunteer who records daily weather observations, such as maximum and minimum temperatures, precipitation...
Coordinated Universal TimeBy international agreement, the local time at the prime meridian, which passes through Greenwich, England...
Coplane scanningA radar scanning strategy where two or more radar antennas are positioned to scan the same atmospheric volume...
Copolarized signalThe component of a radar signal that has the same polarization as the transmitted signal, after being...
CORCorrection
Corange lineA line on a chart joining points that have the same tidal range, the difference in height between high water...
CordonazoA violent storm of the west coast of Mexico, in many cases a tropical cyclone from the eastern Pacific...
Cordonazo de San FranciscoA period of stormy weather, including strong winds and heavy rain, that occurs along the Pacific coast of...
Core punch[Slang], a penetration by a vehicle into the heavy precipitation core of a thunderstorm.
Core sampleA cylindrical section of material, such as ice, sediment, or rock, extracted from a larger body for...
Coriolis accelerationAn apparent acceleration experienced by objects moving within a rotating frame of reference, acting...
Coriolis effectThe apparent deflection of moving objects when viewed from a rotating frame of reference, such as the Earth...
Coriolis forceAn apparent force that deflects moving objects in a rotating reference frame, such as the Earth. It acts...
Coriolis parameterA scalar quantity that represents twice the vertical component of the Earth's angular velocity, influencing...
Corn heat unitA measure used in agriculture to quantify the amount of heat available for corn growth and development during...
Corn snow iceIn hydrologic terms, rotten granular ice.
Corner effectsA small-scale convergence effect that can be quite severe. It occurs around steep islands and headlands.
CorniceAn overhanging mass of snow formed by wind deposition on the leeward side of a ridge or cliff. These...
CoromellA nocturnal south to southwest wind at La Paz on the Baja California peninsula, occurring mainly in late...
CoronaA luminous atmospheric optical phenomenon appearing as a set of colored rings or a colored disk immediately...
Corona currentAn electric current that flows from a pointed or thin conductor into the surrounding air when the electric...
Corona dischargeA localized electrical discharge that occurs when the electric field around a conductor is strong enough to...
CoronagraphA telescope fitted with an occulting disk that blocks the bright solar disk and creates an artificial...
Coronal holeA region in the sun's corona where the plasma is cooler and less dense than its surroundings, and the...
Coronal mass ejectionA massive burst of solar wind and magnetic fields released from the sun's corona into space. These ejections...
Coronal rain(Abbrev. CRN) In solar-terrestrial terms, material condensing in the corona and appearing to rain down into...
Coronal transientsIn solar-terrestrial terms, a general term for short-time-scale changes in the corona, but principally used...
Co-rotating Interaction RegionA region in the solar wind formed by the interaction of a fast stream of solar wind with a slower stream...
Corpuscular theory of lightA historical physical model, prominently supported by Isaac Newton, proposing that light consists of a stream...
CorrasionThe erosional process by which rock and other surfaces are worn away by the abrasive action of solid...
Corrected altitudeThe true vertical distance of an aircraft or object above mean sea level, adjusted for atmospheric pressure...
CorrectionAn adjustment applied to a measured or observed value to account for known errors, biases, or non-standard...
Correlated shearAn output of the mesocyclone detection algorithm indicating a 3-dimensional shear region (i.e. vertically...
Correlated-kA method used in atmospheric radiative transfer models to efficiently calculate the absorption and emission...
CorrelationA statistical measure that describes the extent to which two or more variables tend to change together. In...
Correlation coefficientA dimensionless statistical measure that quantifies the strength and direction of a linear relationship...
Correlation ratioA statistical measure that quantifies the strength of the relationship between two variables, without...
Correlative meteorologyA branch of meteorology that analyzes weather data with correlation methods, usually looking for...
CorrelogramA graphical representation of the autocorrelation function of a time series, showing the correlation between...
Corresponding pointA specific location on the Earth's surface that is identifiable in two or more overlapping images, such as...
CorrosionThe gradual degradation of materials, particularly metals, through chemical or electrochemical reactions with...
Cosine law of illuminationA physical law stating that the irradiance, or luminous flux, on a surface is directly proportional to the...
Cosmic radiationHigh-energy radiation originating from outside the Earth's atmosphere, primarily from galactic and solar...
Cosmic rayAn extremely energetic (relativistic) charged particle.
Cosmic raysHigh-energy particles, primarily protons and atomic nuclei, that originate from sources outside our solar...
Cosmic-ray ionizationThe process by which high-energy particles originating from outer space, known as cosmic rays, collide with...
Cosmogenic radioisotopesRadioactive isotopes produced in the Earth's atmosphere or crust by the interaction of cosmic rays with...
CospectrumA mathematical function that describes the contribution of different frequencies to the covariance between...
Cotidal hourA measure of the time interval between the moon's transit over the Greenwich meridian and the occurrence of...
Cotidal lineA line on a map connecting points where high tide occurs simultaneously. These lines illustrate the...
Cotton-region shelterA white-painted, wooden, single-louvered instrument shelter that became the standard thermometer enclosure of...
Couette flowThe laminar flow of a viscous fluid between two parallel plates, where one plate is stationary and the other...
CounterAn instrument designed to detect and quantify individual particles or events, such as raindrops, ice...
CountercurrentA flow that moves in an opposite direction to another adjacent flow. This configuration is common in...
Counter-gradientA transport of a quantity such as heat or moisture in the direction opposite to that expected from its mean...
Counter-gradient fluxA net transport of a scalar quantity, such as heat or moisture, that occurs in the direction of increasing...
Countergradient windA wind whose direction is opposite to that of the horizontal pressure gradient force, which points from high...
CounterradiationThe longwave infrared radiation emitted downward from the atmosphere to the Earth's surface. This process is...
CountertradesWinds that blow in a direction opposite to the prevailing trade winds, typically found at higher altitudes...
CountsThe raw numerical output from a sensor or instrument, representing the number of detected events or units of...
County warning and forecast areaThe group of counties for which a National Weather Service Forecast Office is responsible for issuing...
County warning areaThe group of counties for which a National Weather Service Forecast Office is responsible for issuing...
Coupled atmosphere-ocean modelSame as Coupled Model; in the context of climate modeling this usually refers to a numerical model which...
Coupled modelA numerical model that integrates two or more distinct components of the Earth system, such as the...
Coupled ocean-atmosphere general circulation modelA sophisticated numerical model that simulates the interactions between the Earth's atmosphere and oceans to...
CoupletAdjacent maxima of radial velocities of opposite signs.
Courant-Friederichs-Lewy conditionA necessary condition for the numerical stability of explicit finite difference methods used to solve partial...
CovarianceA statistical measure that quantifies the degree to which two random variables change together. A positive...
Covariance matrixA square matrix that displays the covariances between pairs of different variables in its off-diagonal...
CPCClimate Prediction Center
CrabbingThe technique used by an aircraft pilot to maintain a straight ground track in crosswind conditions by...
CrachinA type of persistent, light rain or drizzle that occurs in the coastal regions of southern China and Vietnam...
CrackA fracture or fissure that forms in a solid material, such as ice or rock, due to stress. In glaciers and ice...
CreekA small stream of water which serves as the natural drainage course for a drainage basin of nominal, or small...
CreepThe slow, continuous deformation of a material under constant stress over an extended period, even at...
Creeping flowA fluid flow characterized by a very low Reynolds number, where viscous forces dominate over inertial forces...
Crepuscular raysBeams of sunlight that appear to radiate from a single point in the sky, often visible around sunrise or...
CrestHighest point in a wave.
Crest cloudA stationary cloud formation that develops over the crest of a mountain range or ridge. These clouds form...
Crest gageA gage used to obtain a record of flood crests at sites where recording gages are installed.
Crest gaugeA device used to measure and record the maximum water level, or crest, reached in a stream or river during a...
Crest stageThe highest water level or elevation reached by a body of water, such as a river or stream, during a flood or...
Crest widthIn hydrologic terms, the thickness or width of a dam at the level of the crest (top) of the dam. The term...
CrevasseA deep, open crack or fissure found in a glacier or ice sheet, formed by the differential movement and stress...
Crevasse hoarLarge, delicate ice crystals that form within the open spaces of a crevasse in a glacier. These crystals grow...
Criegee intermediateA highly reactive, short-lived molecule with a zwitterionic structure, formally known as a carbonyl oxide. It...
Criteria pollutantsA group of common air pollutants regulated by national ambient air quality standards due to their known...
Critical depthThe depth of water in an open channel at which the specific energy is at a minimum for a given discharge. At...
Critical dischargeThe maximum flow rate that a channel or conduit can pass under conditions of critical flow for a given...
Critical drop radiusThe minimum radius a water droplet must possess to grow by condensation in a supersaturated environment...
Critical flowA condition in fluid dynamics where the flow velocity equals the speed of a small amplitude wave in the...
Critical frequencyThe highest frequency at which a radio wave, when transmitted vertically, is reflected back to Earth by an...
Critical gradientThe specific vertical temperature lapse rate at which an air parcel, when displaced, remains in neutral...
Critical levelA specific altitude in the atmosphere where the phase speed of an atmospheric wave matches the mean flow...
Critical level of escapeThe altitude in a planetary atmosphere where the mean free path of an atmospheric constituent becomes...
Critical pointThe specific temperature and pressure at which the liquid and gas phases of a substance become...
Critical rainfall probability(Abbrev. CRP) - In hydrologic terms, the Probability that the actual precipitation during a rainfall event...
Critical richardson numberA dimensionless parameter that indicates the threshold for the onset of turbulence in a stratified fluid...
Critical tidal levelA specific elevation within the intertidal zone where the duration of continuous submergence or exposure to...
Critical velocityThe specific speed at which a fluid transitions from laminar to turbulent flow, or vice versa, within a given...
CrivetzA cold, strong, and dry wind that blows from the northeast across Romania, particularly affecting the eastern...
CRNCoronal Rain - In solar-terrestrial terms, material condensing in the corona and appearing to rain down into...
CrochetIn solar-terrestrial terms, a sudden deviation in the sunlit geomagnetic field (H component; see geomagnetic...
Crop calendarA schedule that outlines the typical timing of agricultural activities for specific crops in a given region...
Crop coefficientA dimensionless factor used in agricultural meteorology to relate the evapotranspiration of a specific crop...
Crop moisture indexA weekly index of the moisture available to crops over the short term, computed from the week's mean...
Cross correlationA statistical measure that quantifies the similarity between two time series as a function of the time lag...
Cross seaA sea state where two or more wave systems, generated by different wind fields or propagating from different...
Cross sectionA two-dimensional representation of atmospheric variables along a specific line or plane, often vertical or...
Cross-isobar angleThe angle at which the wind flows across lines of constant atmospheric pressure (isobars) in the lower...
Cross-polarized signalA radar echo component whose polarization is orthogonal to that of the transmitted wave, produced mainly when...
Cross-sectional analysisThe analysis of the atmosphere along a vertical plane, a graphic slice from the ground up to a chosen...
Cross-spectrumA mathematical function that describes the frequency-domain relationship between two time series, indicating...
Cross-valley windA wind flow that blows perpendicular to the main axis of a valley, often driven by larger-scale synoptic...
Cross-valley wind systemA thermally driven wind that blows during daytime across the axis of a valley toward the heated sidewall.
CrosswindA wind component that blows perpendicular to a specified direction of motion or alignment, such as a runway...
Crosswise vorticityThe component of vorticity that is perpendicular to the direction of the mean flow. This type of vorticity is...
Crown fireA fire where flames travel from tree to tree at the level of the tree's crown or top.
CrowningMovement of a fire from the understory into the crown of a forest canopy.
CRPCritical Rainfall Probability - in hydrologic terms, the probability that a given rainfall will cause a...
CRSConsole Replacement System for NOAA Weather Radio
Cryoconite holeA small, water-filled depression on the surface of a glacier or ice sheet, formed by the melting of ice...
Cryogenic hygrometerAn instrument designed to measure atmospheric humidity by cooling a surface until condensation or frost...
Cryogenic periodA time period in geologic history during which large bodies of ice appeared at or near the poles and the...
CryologyThe scientific study of snow and ice in all forms, including glaciers, ice sheets, sea ice, lake and river...
CryopedologyThe study of frozen soils and their properties, including permafrost, seasonally frozen ground, and the...
CryoplanationA geomorphic process involving the leveling or reduction of landforms in periglacial environments due to...
CryoplanktonMicroscopic organisms, primarily algae and bacteria, that inhabit frozen environments such as sea ice...
CryosphereThe portions of Earth's surface where water exists in solid form, including glaciers, ice sheets, snow cover...
CryptoclimateThe microclimate within a confined space, such as a cave, rock shelter, or beneath a dense canopy of...
CryptoclimatologyThe study of the climate within hidden or enclosed environments, such as caves, soils, or dense forest...
CrystalA solid material in which the constituent atoms, molecules, or ions are arranged in a highly ordered...
Crystal habitThe characteristic external shape or morphology of an individual crystal, reflecting its internal atomic...
Crystal latticeThe regular, repeating three-dimensional arrangement of atoms, ions, or molecules within a crystalline solid...
Crystalline frostA deposit of ice crystals that forms on surfaces when the temperature of the surface is below freezing and...
CrystallizationThe process by which a solid forms, where atoms or molecules are highly organized into a structure known as a...
Crystallization nucleusA microscopic particle in the atmosphere that serves as a site for the initiation of ice crystal formation...
CSDRBLConsiderable
CSIA form of atmospheric instability in a saturated, rotating, sheared environment that is stable to purely...
CSTCentral Standard Time
CSTLcoastal
CTYcity
CUCumulus clouds - Detached clouds, generally dense and with sharp outlines, showing vertical development in...
Cubic feet per second(Abbrev. CFP) - In hydrologic terms, a unit expressing rates of discharge. One cubic foot per second is equal...
CUFRACumulus Fractus
Cum soleA Latin phrase meaning "with the sun" that describes motion in the same direction as the sun's apparent path...
CumuliformDescribing clouds that are heaped, puffy, or lumpy in appearance, with flat bases and vertical development...
Cumuliform anvilA thunderstorm anvil with visual characteristics resembling cumulus-type clouds (rather than the more typical...
CumulonimbusA dense and towering vertical cloud that brings thunderstorms, heavy rain or hail, and strong, gusty winds...
Cumulonimbus calvusA cumulonimbus cloud that has not yet developed a fibrous or striated upper part, meaning its top still...
Cumulonimbus capillatusA mature cumulonimbus cloud characterized by a distinct, fibrous, or striated upper part, often resembling...
CumulusA genus of low-level, detached clouds characterized by flat bases and puffy, cotton-like tops that can grow...
Cumulus buildupsClouds which develop vertically due to unstable air. Characterized by their cauliflower-like or tower-like...
Cumulus congestusA moderately developed cumulus cloud with a towering, cauliflower-like appearance, indicating strong vertical...
Cumulus fractusA species of cumulus cloud that appears as small, ragged, and broken fragments, often with a shredded...
Cumulus humilisA species of cumulus cloud with a distinct, flat base and only slight vertical development, making it appear...
Cumulus mediocrisCumulus clouds of moderate vertical development, with tops that are slightly rounded and show some growth...
Cunnane plotting positionA formula used in hydrology and meteorology to estimate the exceedance probability of an event from a sample...
Cunningham slip correctionA factor applied to Stokes' law to account for the non-continuum effects experienced by very small particles...
Cup anemometerAn instrument designed to measure wind speed, consisting of three or four hemispherical or conical cups...
Cup crystalA large faceted ice grain shaped like a hollow hexagonal cup, the typical crystal of depth hoar in a...
CurieA non-SI unit of radioactivity, defined as the activity of a quantity of radioactive material in which 3.7 x...
Curie temperatureThe critical temperature above which certain ferromagnetic materials lose their permanent magnetic properties...
CurlA vector operator that describes the infinitesimal rotation of a three-dimensional vector field. In...
CurrentA continuous, directed movement of a fluid, such as water or air, within a larger body of that fluid. In the...
Current chartA graphical representation depicting the speed and direction of ocean currents or atmospheric flows over a...
Current cross sectionA two-dimensional slice through a body of fluid, illustrating the distribution of current velocities and...
Current curveA graphical representation showing the variation of current speed or direction over time at a specific...
Current ellipseA graphical representation of the oscillatory motion of tidal currents over a complete tidal cycle at a...
Current functionA scalar field used in fluid dynamics to represent a two-dimensional, incompressible flow. Its isolines are...
Current meterAn instrument designed to measure the speed and direction of fluid flow, typically in water or air. Common...
Current poleA simple device used to measure the speed and direction of surface water currents. It consists of a weighted...
Current profilerA specialized instrument that measures the speed and direction of fluid currents at multiple depths or...
Current roseA graphical diagram that illustrates the frequency distribution of current speeds and directions at a...
Current tablesPublished compilations of predicted tidal current speeds and directions for specific locations and times...
Curtain drainIn hydrologic terms, a drain constructed at the upper end of the area to be drained, to intercept surface or...
Curtis-Godson approximationA method used in radiative transfer calculations to simplify the treatment of non-homogeneous atmospheric...
Curve fittingThe process of constructing a mathematical function that best fits a series of data points, often subject to...
Curve of growthA graphical representation showing the relationship between the equivalent width of an absorption line in a...
Curvilinear coordinatesA coordinate system in which the coordinate lines are curves rather than straight lines, allowing for a more...
Custard windsA local or historical name for cold, damp, and persistent easterly or northeasterly winds, particularly noted...
CutoffIn hydrologic terms, from passing through a dam’s foundation material. An impervious construction or material...
Cutoff highA high-pressure system that has become detached or isolated from the main belt of westerlies, often moving...
Cutoff lowA low-pressure system that has become separated or isolated from the main westerly flow aloft, often moving...
Cutting-off processThe atmospheric phenomenon where a high or low-pressure system becomes separated from the main zonal flow...
CVRCover
CWACounty Warning Area
CWFACounty Warning and Forecast Area
CyanometerAn instrument designed to measure the blueness of the sky, typically by comparing the sky's color to a graded...
CYCCyclone- A large-scale circulation of winds around a central region of low atmospheric pressure...
CycleA sequence of events or phenomena that repeats over time, often involving a return to an initial state. In...
Cycle per secondA unit of frequency, representing one complete oscillation or repetition of a periodic phenomenon occurring...
CYCLGNCyclogenesis - The formation or intensification of a cyclone or low-pressure storm system.
Cyclic stormA thunderstorm that undergoes cycles of intensification and weakening (pulses) while maintaining its...
CyclogenesisThe process of formation or intensification of a cyclonic circulation, which is a low-pressure area with...
Cyclo-geostrophic currentA wind or ocean current that represents a balance between the Coriolis force, the pressure gradient force...
CyclolysisThe process of weakening or dissipation of a cyclone. This occurs when the atmospheric conditions that...
CycloneA large-scale atmospheric system characterized by a low-pressure center around which air flows inward and...
Cyclone collectorA device used to remove particulate matter from an air or gas stream without the use of filters, through...

1,012 of 10,702 terms in Meteorology and atmospheric science terminology (MLC-0110). Request the full dataset.