Meteorology and atmospheric science terminology · MLC-0110

Meteorology and atmospheric science terms: A (888)

Page 1 of 2

• A1. Abbrevation for hail in weather observations.
• A AMSArctic Air Mass
• A indexA daily index of geomagnetic activity derived as the average of the eight 3-hourly a indices.
• AAASAmerican Association for the Advancement of Science
• AAWUAlaskan Aviation Weather Unit
• AbatementThe process of reducing the intensity or severity of a meteorological phenomenon or its effects. This can...
• AbductionA form of logical inference used in weather forecasting to determine the most plausible explanation for a set...
• AbioticRelating to the non-living physical and chemical components of an ecosystem that influence atmospheric...
• AblationThe process by which ice and snow are lost from a glacier, ice sheet, or snowpack through melting...
• Ablation areaThe lower part of a glacier or ice sheet where the annual loss of ice and snow due to melting, sublimation...
• ABNDTAbundant
• AbnormalDescribing a meteorological condition or event that deviates significantly from the typical or expected range...
• AbnormalityA deviation from the typical or expected atmospheric conditions or meteorological patterns for a given...
• Abrolhos squallsStrong, localized wind gusts and thunderstorms that develop off the coast of Western Australia, particularly...
• AbscissaThe horizontal coordinate in a two-dimensional Cartesian coordinate system, representing the independent...
• AbsoluteReferring to a measurement or value that is independent of any arbitrary reference point or scale, often...
• Absolute altitudeThe vertical distance of an aircraft or object above the actual terrain directly below it. This measurement...
• Absolute angular momentumA measure of the rotational inertia of a parcel of air or fluid, relative to a fixed point in space. It is...
• Absolute annual range of temperatureThe difference between the highest and lowest air temperatures recorded at a specific location over an entire...
• Absolute cavity radiometerA highly precise instrument designed to measure the total solar irradiance by converting absorbed radiation...
• Absolute coordinate systemA reference frame that is fixed in space and does not rotate with the Earth. In this system, the Earth's...
• Absolute droughtA period of at least 15 consecutive days during which the daily rainfall at a specific location is less than...
• Absolute extremesThe highest or lowest values of a meteorological variable ever recorded at a particular location over its...
• Absolute instabilityAn atmospheric condition where a parcel of air, if displaced vertically, will accelerate away from its...
• Absolute instrumentA measuring device that determines the value of a physical quantity directly from its fundamental properties...
• Absolute isohypseA line on a weather map connecting points of equal geopotential height on a specific constant-pressure...
• Absolute momentumThe sum of the momentum of an air parcel relative to the Earth's surface and the momentum due to the Earth's...
• Absolute monthly maximum temperatureThe highest temperature ever recorded during a specific calendar month at a given location over the entire...
• Absolute monthly minimum temperatureThe lowest temperature ever recorded during a specific calendar month at a given location over the entire...
• Absolute radiation scaleA historical standard for measuring solar irradiance, established in 1956 to unify measurements from...
• Absolute refractive indexA dimensionless quantity representing the factor by which the phase velocity of electromagnetic radiation is...
• Absolute stabilityA state of the atmosphere where a parcel of air, when displaced vertically, tends to return to its original...
• Absolute standard barometerA mercury barometer designed and calibrated to provide highly accurate measurements of atmospheric pressure...
• Absolute temperature extremesThe highest and lowest air temperatures ever recorded at a specific geographical location since observations...
• Absolute velocityThe velocity of a fluid parcel or object as measured from a fixed, non-rotating frame of reference, such as...
• Absolute vorticityA measure of the total rotation of an air parcel in the atmosphere, combining both its rotation relative to...
• Absolute zeroThe theoretical lowest possible temperature at which a substance has no kinetic energy and all atomic motion...
• Absolutely stable airAn atmospheric condition that exists when the environmental lapse rate is less than the moist adiabatic lapse...
• Absolutely unstable airAn atmospheric condition that exists when the environmental lapse rate is greater than the dry adiabatic...
• AbsorbanceA measure of the amount of light absorbed by a substance as it passes through it, often expressed as the...
• Absorbed solar radiationThe portion of incoming solar radiation that is taken up by the Earth's surface and atmosphere, converting it...
• AbsorptanceThe ratio of the radiant flux absorbed by a body to the radiant flux incident upon it. This dimensionless...
• AbsorptionThe process by which electromagnetic radiation is taken up by a substance, such as an atmospheric gas...
• Absorption bandA range of wavelengths or frequencies within the electromagnetic spectrum where a substance absorbs radiation...
• Absorption coefficientA quantitative measure of how strongly a substance absorbs electromagnetic radiation at a particular...
• Absorption cross sectionA measure of the probability that a photon will be absorbed by an atom or molecule. It represents the...
• Absorption hygrometerAn instrument that measures atmospheric humidity by detecting changes in the physical or electrical...
• Absorption lineA narrow, dark line in an otherwise continuous spectrum, caused by the absorption of specific wavelengths of...
• Absorption lossThe reduction in the intensity of electromagnetic radiation as it passes through a medium due to its...
• Absorption optical thicknessA dimensionless quantity that describes the extent to which a medium absorbs radiation along a given path. It...
• Absorption spectrumA plot showing the amount of electromagnetic radiation absorbed by a substance across a range of wavelengths...
• AbsorptivityThe ability of a material to absorb electromagnetic radiation, often referring to the fraction of incident...
• AbstractionThe combined effect of processes that remove water from precipitation before it can contribute to surface...
• ABTAbout
• AbutmentThe part of a valley or canyon wall against which a dam is constructed. Right and left abutments are those on...
• Abutment seepingReservoir water that moves through seams or pores in the natural abutment material and exits as seepage.
• ABVAbove
• AC1. Abbreviation for Altocumulus - a cloud of a class characterized by globular masses or rolls in layers or...
• ACCAS(usually pronounced ACK-kis) - AltoCumulus CAStellanus; mid-level clouds (bases generally 8 to 15 thousand...
• Accelerated erosionErosion that occurs at a rate significantly higher than the natural geological rate, often due to human...
• AccelerationThe rate of change of velocity of an object or fluid parcel with respect to time. It is a vector quantity...
• AccelerometerAn instrument designed to measure proper acceleration, which is the acceleration experienced by an object...
• Acceptance regionThe range of values for a test statistic in a hypothesis test that leads to the conclusion that the null...
• Accessory cloudA supplementary cloud formation that is associated with a larger, main cloud and often develops from it or is...
• AcclimationThe process by which an organism adjusts its physiology or behavior in response to changes in its immediate...
• AcclimatizationThe process by which an organism adjusts physiologically or behaviorally to changes in its environment, such...
• AccretionThe growth of a precipitation particle by the collision and coalescence of a frozen hydrometeor with...
• ACCUMSaccumulation
• Accumulated coolingThe cumulative reduction in temperature over a specified period, often expressed as degree-days below a...
• Accumulated temperatureA measure of heat input over time, calculated by summing daily mean temperatures above a specific base...
• AccumulationThe net gain of mass at a surface, typically referring to the addition of snow, ice, or water. This process...
• Accumulation areaThe upper part of a glacier or ice sheet where the annual gain of snow and ice mass exceeds the annual loss...
• Accumulation modeA size range of atmospheric aerosol particles, typically between 0.1 and 1.0 micrometers in diameter, formed...
• Accumulation rain gaugeAn instrument that collects precipitation over a period and holds it for later measurement. It consists of a...
• Accumulation zoneThe region of a glacier or ice sheet where the annual snowfall and other forms of solid precipitation exceed...
• AccuracyThe degree of closeness between a measurement or forecast and the true or accepted value of the quantity...
• AcdarAn acronym for acoustic detection and ranging, a remote sensing technique that uses sound waves to probe the...
• AcetaldehydeAn organic compound (CH3CHO) present in the atmosphere as a pollutant and a product of natural processes. It...
• Acetic acidA carboxylic acid with the chemical formula CH3COOH, present in the atmosphere as a volatile organic...
• AcetoneA volatile organic compound (VOC) with the chemical formula (CH3)2CO, found in the atmosphere from both...
• AcetonitrileAn organic compound with the chemical formula CH3CN, present in the atmosphere primarily as a tracer for...
• AcetyleneA hydrocarbon gas with the chemical formula C2H2, found in the atmosphere as a result of incomplete...
• Acicular iceIce crystals characterized by a needle-like or columnar shape, often observed in cirrus clouds or during...
• Acid depositionThe process by which acidic compounds, primarily sulfuric and nitric acids, are removed from the atmosphere...
• Acid fogFog that has become highly acidic due to the dissolution of atmospheric pollutants, primarily sulfur dioxide...
• Acid pollutionThe contamination of the atmosphere, land, and water bodies by acidic substances, primarily sulfur dioxide...
• Acid precipitationPrecipitation, such as rain, snow or sleet, containing relatively high concentrations of acid-forming...
• Acid rainPrecipitation, including rain, snow, or hail, that is unusually acidic due to the presence of elevated levels...
• Acidity of waterA measure of the concentration of hydrogen ions (H+) in an aqueous solution, expressed by the pH scale. In...
• Acidity profileA vertical distribution or temporal trend of acidity measurements within a medium, such as an ice core, soil...
• ACLDAbove Cloud Level
• Aclinic lineAn imaginary line on the Earth's surface connecting points where the magnetic dip or inclination is zero...
• Acoustic arrayA system of multiple microphones or other acoustic sensors arranged in a specific geometric pattern to detect...
• Acoustic backscatteringThe reflection of sound waves back towards their source after encountering particles or inhomogeneities in...
• Acoustic dispersionThe phenomenon where the speed of sound in a medium varies with the frequency of the sound wave. In the...
• Acoustic Doppler current profilerAn instrument that measures water current velocities over a range of depths using the Doppler effect of sound...
• Acoustic echo soundingA remote sensing technique that uses sound waves to probe the lower atmosphere, particularly the atmospheric...
• Acoustic imagingThe process of creating visual representations of objects or environments using sound waves. In atmospheric...
• Acoustic impedanceA measure of the opposition a medium presents to the propagation of sound waves, defined as the product of...
• Acoustic intensityThe average rate of sound energy flow per unit area perpendicular to the direction of wave propagation. It is...
• Acoustic lensA device that refracts or diffracts sound waves to focus or collimate them, analogous to how an optical lens...
• Acoustic ocean current meterAn instrument that measures water velocity by transmitting acoustic pulses and detecting the Doppler shift of...
• Acoustic pressureThe local deviation from the ambient atmospheric pressure caused by the passage of a sound wave. It...
• Acoustic radarA remote sensing instrument that uses sound waves to probe the lower atmosphere, detecting variations in...
• Acoustic rain gaugeA device that measures rainfall by detecting the sound produced by raindrops impacting a surface or by...
• Acoustic reflection profilingA geophysical technique that uses sound waves to map subsurface structures by analyzing the reflections from...
• Acoustic reflectivityThe fraction of incident acoustic energy that is reflected from a boundary or discontinuity within a medium...
• Acoustic refractionThe bending of sound waves as they pass through a medium with varying sound speed, which is influenced by...
• Acoustic resonanceThe phenomenon where an atmospheric system or cavity vibrates with maximum amplitude at specific frequencies...
• Acoustic reverberationThe persistence of sound in an enclosed space or medium after the direct sound source has stopped, caused by...
• Acoustic scatteringThe redirection of sound waves in multiple directions as they encounter inhomogeneities or obstacles within a...
• Acoustic scintillationThe random fluctuations in the amplitude and phase of an acoustic wave as it propagates through a turbulent...
• Acoustic signatureThe characteristic pattern of sound waves emitted or reflected by a specific atmospheric phenomenon or...
• Acoustic soundingA remote sensing technique that uses sound waves to probe the lower atmosphere, primarily to measure wind...
• Acoustic thermometerAn instrument that measures air temperature by determining the speed of sound through a specific path in the...
• Acoustic tomographyA technique that reconstructs a two- or three-dimensional image of atmospheric properties, such as...
• Acoustic transducerA device that converts electrical energy into sound waves or vice versa. In atmospheric science, transducers...
• Acoustic transponderA device that receives an acoustic signal and, in response, transmits another acoustic signal. While less...
• Acoustic velocimeterAn instrument that measures the speed of sound in a medium, which can then be used to infer other properties...
• Acoustic waveA type of mechanical wave that propagates through a medium by means of oscillations of the particles of the...
• Acoustic-gravity waveA type of atmospheric wave that propagates through a compressible fluid medium, such as the atmosphere, under...
• ACPYAccompany
• Acre-footThe amount of water required to cover one acre to a depth of one foot. An acre-foot equals 326,851 gallons...
• AcroleinA highly reactive and toxic unsaturated aldehyde with the chemical formula CH2=CHCHO, characterized by a...
• ACRSAcross
• ActinicRelating to electromagnetic radiation that is capable of causing photochemical reactions, particularly in the...
• Actinic fluxThe total radiant energy per unit area per unit time, integrated over all directions, that is capable of...
• ActinogramA graphical record produced by an actinograph, showing the intensity of solar radiation over a period of...
• ActinographA self-recording instrument designed to continuously measure and record the intensity of solar radiation. It...
• ActinometerAn instrument used to measure the intensity of solar radiation, particularly the actinic or chemically active...
• ActinometryThe science and practice of measuring the intensity and heating power of electromagnetic radiation...
• ActinonAn obsolete name for the isotope Radon-219 (219Rn), a naturally occurring radioactive noble gas. It is a...
• Action stageThe stage which, when reached by a rising stream, represents the level where the NWS or a partner/user needs...
• Activated complex theoryA theoretical framework that describes the rates of chemical reactions by considering a transition state, or...
• Activation energyThe minimum amount of energy required for a chemical reaction to occur, leading to the formation of an...
• Active(abbrev. ACTV). In solar-terrestrial terms, solar activity levels with at least one geophysical event or...
• Active basin areaThe portion of a drainage basin that contributes directly to runoff during a precipitation event. This area...
• Active cloudA cloud undergoing vertical development and producing precipitation, characterized by strong internal...
• Active conservation storageIn hydrologic terms, the portion of water stored in a reservoir that can be released for all useful purposes...
• Active Dark FilamentIn solar-terrestrial terms, an Active Prominence seen on the Disk.
• Active frontA weather front that produces a distinct band of clouds and precipitation. Strong temperature and moisture...
• Active layerThe uppermost layer of ground in permafrost regions that thaws in the summer and refreezes in the winter. Its...
• Active longitudeIn solar-terrestrial terms, the approximate center of a range of heliographic longitudes in which Active...
• Active nitrogenA form of nitrogen gas that has been excited into a more chemically reactive state than its normal diatomic...
• Active permafrostPermafrost that is currently undergoing degradation, characterized by a deepening of the active layer or an...
• Active prominenceIn solar-terrestrial terms, a prominence displaying material motion and changes in appearance over a few...
• Active Prominence RegionIn solar-terrestrial terms, a portion of the solar limb displaying active prominences.
• Active regionA localized, transient area on the Sun's photosphere characterized by an exceptionally strong and complex...
• Active siteA specific region on the surface of a catalyst, such as an atmospheric aerosol particle or ice crystal, where...
• Active storage capacityIn hydrologic terms, the total amount of reservoir capacity normally available for release from a reservoir...
• Active Surge RegionIn solar-terrestrial terms, an Active Region that exhibits a group or series of spike-like surges that rise...
• Active systemA weather system, such as a cyclone, front, or convective complex, that is currently producing or is forecast...
• ActivityA thermodynamic measure of the effective concentration of a substance in a mixture, accounting for non-ideal...
• Activity coefficientA dimensionless factor that relates the activity of a chemical species to its concentration in a non-ideal...
• Actual elevationThe true vertical distance of a point or object above a specified datum, most commonly mean sea level. For a...
• Actual evaporationThe amount of water vapor transferred from a surface, such as land or water, to the atmosphere under existing...
• Actual pressureThe measured atmospheric pressure at a specific location and time, without any adjustments for altitude or...
• ACTVActive. In solar-terrestrial terms, solar activity levels with at least one geophysical event or several...
• ACYCAnticyclone - A large-scale circulation of winds around a central region of high atmospheric pressure...
• A/D converterAn electronic device that transforms an analog electrical signal, such as voltage or current from a sensor...
• AdaptabilityThe capacity of a system or organism to adjust to changing environmental conditions, particularly in response...
• ADAPTATION (ADAPTABLE) PARAMETERGenerally, data related to a specific WSR-88D unit. These data may consist of meteorological or hydrological...
• Adaptation luminanceThe average luminance level to which the human visual system has adjusted, influencing how brightness and...
• Adaptation strategiesPlanned actions or adjustments undertaken by human systems or natural systems in response to actual or...
• Adaptive gridA computational mesh used in numerical weather prediction and climate models where the resolution varies...
• Adaptive observational networkA system of meteorological sensors and platforms whose deployment or sampling strategy can be dynamically...
• Adaptive observationsMeteorological measurements specifically designed and deployed to reduce forecast uncertainty for a...
• ADASAutomated Data Acquisition System
• Additive dataA group of coded remarks that includes pressure tendency, amount of precipitation, and maximum/minimum...
• ADDSAviation Digital Data Service
• AdfreezingThe process by which a frozen layer of soil or ice adheres to and exerts upward or downward forces on an...
• Adhesion efficiencyThe probability that a cloud droplet or ice crystal will stick to another particle upon collision, rather...
• Adhesive waterWater molecules that are held tightly to the surfaces of soil particles or other solid materials through...
• AdiabatA line on a thermodynamic diagram, such as a skew-T log-P chart, that represents an adiabatic process. It...
• AdiabaticChanges in temperature caused by the expansion (cooling) or compression (warming) of a body of air as it...
• Adiabatic atmosphereA hypothetical atmospheric state where the temperature profile is such that a parcel of air, if displaced...
• Adiabatic chartA thermodynamic diagram used to plot atmospheric soundings and analyze the vertical structure of the...
• Adiabatic equilibriumA state in the atmosphere where the vertical temperature gradient is equal to the adiabatic lapse rate...
• Adiabatic lapse rateThe rate at which the temperature of an air parcel changes as it rises or sinks adiabatically, meaning...
• Adiabatic processA thermodynamic process in which a system, such as an air parcel, undergoes changes in temperature and...
• Adiabatic saturation pointThe temperature and humidity state reached by an air parcel when it is cooled adiabatically by evaporation of...
• Adiabatic saturation pressureThe partial pressure of water vapor in an air parcel that has been brought to saturation adiabatically by the...
• Adiabatic saturation temperatureThe lowest temperature to which an air parcel can be cooled by evaporating water into it, provided that all...
• Adiabatic temperature changesVariations in the temperature of an air parcel that occur solely due to changes in its pressure, without any...
• Adiabatic temperature gradientThe rate at which the temperature of an air parcel changes as it moves vertically through the atmosphere...
• Adiabatically enclosed systemA thermodynamic system that does not exchange heat or mass with its surroundings. Any changes in temperature...
• Adirondack type snow sampling setIn hydrologic terms, a snow sampler consisting of a 5-foot fiberglass tube, 3 inches in diameter, with a...
• A-displayA type of radar display that shows the amplitude of the received radar signal as a vertical deflection...
• ADJAdjacent
• Adjoint assimilationA four-dimensional variational (4D-Var) data assimilation method used in numerical weather prediction to find...
• Adjoint equationA mathematical equation derived from a forward model, used to propagate information backward in time or...
• Adjoint modelA computational model that represents the adjoint of a forward numerical model, such as a weather prediction...
• Adjoint sensitivityThe measure of how much a particular forecast output or objective function changes in response to small...
• Adjustable cistern barometerA mercury barometer featuring a reservoir, or cistern, with a flexible base that can be moved by an adjusting...
• Admissible concentration limitThe maximum permissible concentration of a pollutant or substance in the atmosphere that is considered safe...
• ADPCAcoustic Doppler Current Profiler
• AdretA sun-facing slope in mountainous regions, particularly in the Alps, that receives a greater amount of direct...
• AdsorptionThe process by which molecules of a gas, liquid, or dissolved solid adhere to the surface of a solid or, less...
• Adsorption isothermA graph or mathematical relationship that describes the amount of a substance adsorbed onto a surface as a...
• Advanced Baseline ImagerA primary instrument on the Geostationary Operational Environmental Satellite (GOES) series, providing...
• Advanced Earth Observing SatelliteA series of Japanese Earth observation satellites, also known as ADEOS, designed to monitor global...
• Advanced Hydrologic Prediction ServiceA web-based suite of accurate and information-rich forecast products. They display the magnitude and...
• Advanced microwave sounding unitA multi-channel microwave radiometer flown on polar-orbiting satellites to measure atmospheric temperature...
• Advanced TIROS-NThe designation for a series of polar-orbiting meteorological satellites operated by NOAA, representing an...
• Advanced Very High Resolution RadiometerA broad-band, five-channel radiometer carried on NOAA's polar-orbiting satellites, used for global monitoring...
• ADVCTNAdvection- Transport of an atmospheric property by the wind.
• AdvectionThe horizontal transport of an atmospheric property, such as heat, moisture, or momentum, by the bulk motion...
• Advection fogFog that forms when warm, moist air moves horizontally over a cooler surface, causing the air to cool to its...
• Advection frostA type of frost that forms when cold, moist air moves horizontally over a surface that is already at or below...
• Advective change of temperatureThe change in temperature at a fixed location due to the horizontal movement of air with different thermal...
• Advective modelA mathematical or numerical model that primarily simulates the transport of atmospheric properties, such as...
• Advective regionAn area within the atmosphere where the horizontal transport of properties by the wind is the dominant...
• Advective thunderstormA thunderstorm that develops primarily due to the advection of warm, moist air into a region, leading to...
• ADVISIn hydrologic terms, a program which combines the Antecedent Precipitation Index (API) method of estimating...
• AdvisoryA public statement issued by a meteorological agency to inform the public of hazardous weather conditions...
• Advisory areaA geographical region for which a specific weather advisory has been issued by a meteorological service. This...
• ADVNAdvance
• ADVYAdvisory - Highlights special weather conditions that are less serious than a warning. They are for events...
• AEAn index that measures the global activity of the auroral electrojets, which are intense electric currents...
• AeolianRelating to or arising from the action of the wind. The term describes geological processes, landforms, and...
• Aeolian tonesMusical or whistling sounds produced when wind flows past an obstacle, such as wires, poles, or tree...
• AerationThe process of introducing air into a substance, such as water or soil, or exposing a substance to the air...
• Aeration zoneA portion of the lithosphere in which the functional interstices of permeable rock or earth are not filled...
• AerialA metallic device, also known as an antenna, designed for transmitting or receiving electromagnetic waves. In...
• Aerial perspectiveThe effect of the atmosphere on the appearance of distant objects, causing them to appear less distinct...
• AERO codeA standardized format for transmitting meteorological reports from an aircraft in flight to a ground station...
• AeroallergensAny of a variety of allergens such as pollens, grasses, or dust carried by winds.
• AerobiologyThe study of airborne organic particles, such as pollen, spores, bacteria, and viruses, and their transport...
• Aerodrome meteorological minimaThe minimum meteorological conditions, such as visibility and cloud ceiling, required for aircraft operations...
• AerodynamicRelating to the forces exerted by air or other gases in motion, and the motion of objects through these...
• Aerodynamic balanceAn instrument for measuring the aerodynamic forces and moments acting on a test object within a wind tunnel...
• Aerodynamic forceA mechanical force exerted on an object by the air or other gas through which it moves. This force results...
• Aerodynamic resistanceThe opposition encountered by an object as it moves through the air, primarily due to drag. This resistance...
• Aerodynamic roughness lengthA parameter representing the effective height above a surface where the wind speed theoretically becomes zero...
• Aerodynamically rough surfaceA surface where the roughness elements are large enough to protrude through the viscous sublayer of the...
• Aerodynamically smooth surfaceA surface where the roughness elements are small enough to be entirely submerged within the viscous sublayer...
• AerodynamicsThe study of the motion of air and other gaseous fluids, and of the forces acting on bodies moving through...
• AerographA self-recording instrument that measures and records atmospheric conditions, carried aloft by a kite...
• AerographyThe descriptive study of the atmosphere, focusing on its physical characteristics, phenomena, and...
• AerologationThe practice of observing and studying atmospheric phenomena in the free atmosphere, not in contact with the...
• Aerological daysSpecific days designated for internationally coordinated, intensive upper-air atmospheric observations...
• Aerological stationA meteorological observing station equipped to conduct regular measurements of atmospheric conditions in the...
• Aerological tableA compilation of standard atmospheric data, often presented in tabular format, showing typical values of...
• AerologyThe scientific study of the free atmosphere, particularly its physical properties and phenomena at altitudes...
• AerometeorographA specialized instrument package designed for use on aircraft to continuously record atmospheric pressure...
• Aeronautical climatologyThe study of long-term atmospheric conditions and their statistical properties relevant to aviation...
• Aeronautical meteorological serviceA specialized meteorological service that provides weather information and forecasts specifically tailored...
• Aeronautical meteorological stationA facility established at an aerodrome or other designated location to observe and report meteorological...
• Aeronautical meteorologyThe specialized field of meteorology that focuses on providing weather information and forecasts specifically...
• AeronomyThe scientific study of the upper atmosphere, including its chemical composition, physical properties, and...
• AerosolA collection of minute solid or liquid particles dispersed in a gaseous medium, such as the Earth's...
• Aerosol optical depthA dimensionless measure of the extinction of sunlight by aerosols as it passes through the atmosphere. It...
• Aerosol size distributionA representation of the number, surface area, or mass of aerosol particles as a function of their diameter...
• Aerospace meteorologyThe specialized field of meteorology that addresses atmospheric conditions relevant to both aviation and...
• Aerostatic balanceA device used to measure the density of a gas by comparing the buoyant force it exerts on a body of known...
• AestivalRelating to or characteristic of summer. In meteorology, it describes conditions, phenomena, or climate...
• AestivationA state of animal dormancy, similar to hibernation, that is a response to conditions of high temperature and...
• AFBAir Force Base
• AFCTAffect
• AFDArea Forecast Discussion - This National Weather Service product is intended to provide a well-reasoned...
• AferA hot, dry, southwesterly wind experienced in ancient Italy, believed to originate from Africa. This...
• AfghanetsA strong, hot, and dust-laden southerly or southwesterly wind that occurs in the plains of Central Asia...
• AFOSAutomation of Field Operations and Services. Computer system linking NWS offices for the transmission of...
• AFREDAbbreviation for the A Index for Fredericksburg.
• African Easterly WaveA trough of low pressure that forms over North Africa and moves westward across the continent into the...
• African jetA low-level easterly jet stream located over North Africa during the summer months, also known as the African...
• AFSSAutomated Flight Service Station
• AFTAfter
• AfterbayIn hydrologic terms, the tail race of a hydroelectric power plant at the outlet of the turbines. The term may...
• AfterglowA broad arch of reddish or pinkish light observed in the western sky after sunset, or in the eastern sky...
• AfterheatThe release of sensible heat from the ground surface back into the atmosphere after sunset. During the day...
• Afternoon effectThe tendency for convective activity, such as thunderstorms, to develop or intensify during the late...
• AftersummerA period of unusually warm, calm, and sunny weather that occurs in early autumn, following the typical end of...
• AFTNAfternoon
• AFTRafter
• AFWAAir Force Weather Agency
• AGCAutomatic Gain Control
• AGDISPA particular atmospheric disperison model used for treating the transport and diffusion of aerially sprayed...
• AgeThe time elapsed since a specific atmospheric or oceanic parcel of air or water was last at the surface or in...
• Ageostrophic advectionThe transport of an atmospheric property, such as temperature or vorticity, by the ageostrophic component of...
• Ageostrophic windThe vector difference between the actual wind and the geostrophic wind. This wind component represents the...
• AGFSAviation Gridded Forecast System
• AgglomerateAn ice cover of floe formed by the freezing together of various forms of ice.
• AgglomerationThe process by which individual cloud or precipitation particles collide and stick together, forming larger...
• AggregationThe process where ice crystals collide and stick together to form larger ice particles, such as snowflakes...
• Aggressive waterWater that is corrosive to materials like metal and concrete, typically because it is soft and has a low pH...
• AGLAbove Ground Level
• AGNAgain
• Agonic lineAn imaginary line on the Earth's surface connecting points where the magnetic declination is zero, meaning...
• Agricultural climatologyThe scientific study of the relationship between climate and agriculture, focusing on how climatic factors...
• Agricultural droughtA period of insufficient soil moisture to meet the needs of a particular crop at a specific time, leading to...
• Agricultural meteorological stationA specialized weather station equipped to measure meteorological parameters relevant to agricultural...
• Agricultural meteorologyA branch of applied meteorology that studies the effects of weather and climate on agriculture. It examines...
• Agroclimatic indexA numerical value derived from meteorological parameters that quantifies the suitability of a climate for...
• Agrometeorological forecastingThe practice of creating and disseminating weather predictions tailored specifically for agricultural...
• Agulhas CurrentA warm, swift ocean current that flows southward along the southeastern coast of Africa, originating from the...
• AHDAhead
• AHOSAutomatic Hydrologic Observing System
• AHOS-SAutomatic Hydrologic Observing System - Satellite
• AHOS-TAutomatic Hydrologic Observing System - Telephone
• AirThe mixture of gases that constitutes the Earth's atmosphere, primarily composed of nitrogen (approximately...
• Air acoustic ranging sensorA device that determines distance to an atmospheric feature by emitting sound pulses and measuring the time...
• Air currentA localized movement of air within the atmosphere, characterized by its direction and speed. These currents...
• Air dischargeAn electrical discharge that occurs through the air, which normally acts as an insulator. This phenomenon...
• Air drainageThe flow of cold, dense air down a slope or through a valley under the influence of gravity. This phenomenon...
• Air hoarA type of hoar frost that forms on objects suspended in the air, such as spider webs or fine wires, rather...
• Air massA large body of air, typically thousands of square kilometers in horizontal extent, that possesses relatively...
• Air mass thunderstormGenerally, a thunderstorm not associated with a front or other type of synoptic-scale forcing mechanism. Air...
• Air meterA general name for any instrument designed to measure a physical property of the air. These devices quantify...
• Air parcelA conceptual volume of air, small enough to be considered internally homogeneous in its thermodynamic...
• Air pocketA colloquial expression for a localized downdraft or a region of descending air that causes an aircraft to...
• Air pollutantHarmful substance or product introduced into the atmosphere.
• Air pollutants, see Air pollutant
• Air pollutionThe presence of harmful or undesirable substances in the Earth's atmosphere, occurring at concentrations that...
• Air pollution controlThe implementation of measures and technologies to reduce or prevent the emission of harmful substances into...
• Air pollution episodeA period during which the concentration of atmospheric pollutants in a specific area reaches levels that are...
• Air pollution meteorologyThe study of how atmospheric processes influence the transport, dispersion, transformation, and removal of...
• Air pollution potentialThe meteorological potential for air pollution problems, considered without regard to the presence or absence...
• Air quality alertThis product is used by the National Weather Service to relay non-routine air quality alert messages issued...
• Air quality criteriaScientific documents that summarize the health and environmental effects of specific air pollutants. These...
• Air quality modelMathematical or conceptual model used to estimate present or future air quality.
• Air quality standardsLegally enforceable limits on the concentration of specific pollutants in ambient air, established to protect...
• Air reportA meteorological report issued by an aircraft in flight, providing real-time observations of atmospheric...
• Air samplerA device used to collect atmospheric constituents, such as particulate matter, gases, or biological aerosols...
• Air stagnationA meteorological situation in which there is a major buildup of air pollution in the atmosphere. This usually...
• Air stagnation advisoryThis National Weather Service product is issued when major buildups of air pollution, smoke, dust, or...
• Air temperatureA measure of the kinetic energy of air molecules, indicating how hot or cold the atmosphere is at a...
• Air toxinToxic air pollutant.
• Air toxins, see Air toxin
• Air transportable mobile unitA modularized transportable unit containing communications and observational equipment necessary to support a...
• Air trapA meteorological condition where a mass of air is confined horizontally by topography, such as in a valley or...
• Airborne expendable bathythermographA device deployed from an aircraft to measure ocean temperature as a function of depth. It consists of a...
• Airborne fractionThe proportion of total carbon dioxide emissions from human activities that remains in the atmosphere, rather...
• Airborne particulatesMicroscopic solid or liquid particles suspended in the atmosphere. These can originate from natural sources...
• Airborne snow survey programIn hydrologic terms, Center (NOHRSC) program that makes airborne snow water equivalent and soil moisture...
• Airborne weather radarA radar system installed on an aircraft to detect and display meteorological phenomena, primarily...
• Aircraft ceilingThe maximum altitude an aircraft can maintain under specific atmospheric conditions. This limit is determined...
• Aircraft electrificationThe accumulation of static electric charge on an aircraft's surface due to friction with atmospheric...
• Aircraft icingThe formation and accumulation of ice on an aircraft's external surfaces, including wings, propellers, and...
• Aircraft meteorological stationA system of instruments installed on an aircraft to measure and transmit meteorological parameters during...
• Aircraft observationMeteorological data collected by instruments mounted on aircraft during routine flights or dedicated research...
• Aircraft reportA standardized message transmitted by an aircraft containing meteorological observations made during flight...
• Aircraft soundingThe process of collecting vertical profiles of atmospheric parameters, such as temperature, humidity, and...
• Aircraft thermometryThe measurement of air temperature from an aircraft, a process complicated by the effects of aerodynamic...
• Aircraft turbulenceIrregular and often violent air movements experienced by an aircraft, caused by eddies and vertical currents...
• Aircraft weather reconnaissanceThe use of specially equipped aircraft to fly into or near weather systems to gather detailed atmospheric...
• Aircraft-to-satellite data relayA communication system that automatically transmits meteorological and flight data from an aircraft to a...
• Air-earth conduction currentThe continuous flow of electric charge between the Earth's surface and the atmosphere, driven by the global...
• Air-earth currentThe net flow of electric charge between the Earth's surface and the atmosphere, encompassing both conduction...
• AIREPA standardized format for reporting in-flight weather observations from an aircraft to a ground station...
• Airfield color codeA system of color-coded flags or lights displayed at an airfield to indicate the current flight conditions...
• Air-fuel ratioThe mass ratio of air to fuel present in a combustion process, a key parameter in determining the emissions...
• AirglowFaint, diffuse emission of light from a planetary atmosphere, distinct from aurora, caused by chemical...
• AirlightThe portion of the apparent luminance of a distant object or scene that is contributed by the scattering of...
• Airlight formulaA mathematical expression used to quantify the amount of light scattered by the atmosphere into an observer's...
• Airmass analysisThe process of identifying and characterizing large bodies of air, known as air masses, based on their...
• Airmass classificationA system for categorizing large bodies of air based on their source region and thermal and moisture...
• Airmass climatologyThe study of the frequency, duration, and characteristics of different air masses over a particular region or...
• Airmass modificationThe process by which an air mass changes its temperature, moisture content, and stability as it moves away...
• Airmass precipitationPrecipitation that forms within a single, relatively homogeneous air mass, rather than along a frontal...
• Airmass showerA shower that develops within a single, unstable air mass without the influence of a frontal system or other...
• Airmass source regionA large, geographically uniform area where an air mass acquires its characteristic temperature and moisture...
• AIRMETAirman's Meteorological advisory (WA)
• Airplane observationThe collection of atmospheric data by instruments mounted on an aircraft. These observations provide...
• Airport elevationThe highest point of an airport's usable landing area, measured in feet or meters above mean sea level. This...
• Airport forecastA specialized weather forecast issued for a specific airport, providing detailed information on expected...
• Airshed modelA computational tool used to simulate the transport, dispersion, and chemical transformation of air...
• AirspeedThe velocity of an aircraft or other object relative to the surrounding air mass through which it is moving...
• AirwayA designated route in the atmosphere for aircraft, defined by specific altitudes and geographical...
• Airways shelterA small, standardized enclosure designed to house meteorological instruments, protecting them from direct...
• Aitken dust counterAn instrument used to measure the concentration of very small atmospheric aerosol particles, typically those...
• Aitken nucleusA microscopic aerosol particle with a radius smaller than 0.1 micrometers, serving as a condensation nucleus...
• AIVAviation Impact Variables
• Alarm levelA predetermined threshold value for an environmental parameter, such as pollutant concentration or weather...
• Alaska CurrentA warm, northward-flowing ocean current that branches off the North Pacific Current near the coast of British...
• Alaskan StreamA warm, eastward-flowing ocean current that branches off the North Pacific Current near the coast of British...
• AlbedoThe fraction of incident solar radiation that is reflected by a surface or object. It is a dimensionless...
• AlbedometerAn instrument designed to measure the albedo of a surface, which is the fraction of incident solar radiation...
• Alberta clipperA rapidly moving low-pressure system that forms over or near the Canadian province of Alberta. These systems...
• Alberta lowA type of extratropical cyclone that forms or intensifies over the province of Alberta, Canada, often east of...
• AldehydesA class of organic compounds containing a carbonyl group (C=O) bonded to at least one hydrogen atom. In the...
• ALERTAutomated Local Event Reporting in Real Time. Network of automatic raingauges that transmit via VHF radio...
• Alert stageThe stage which, when reached by a rising stream, represents the level where appropriate officials (e.g...
• Aleutian CurrentA broad, eastward-flowing ocean current in the North Pacific Ocean, located south of the Aleutian Islands. It...
• Aleutian lowA semi-permanent low-pressure system centered near the Aleutian Islands in the North Pacific Ocean...
• Alexander's dark bandA region of reduced brightness located between the primary and secondary rainbows. This optical phenomenon...
• ALFAloft
• Alfvén waveA type of magnetohydrodynamic wave that propagates along magnetic field lines in a conducting fluid, such as...
• ALGAlong
• Algerian CurrentA surface ocean current flowing eastward along the coast of Algeria in the Mediterranean Sea. This current is...
• AlgorithmA finite set of well-defined, unambiguous instructions or rules for solving a problem or performing a...
• AliasingA distortion or artifact that occurs when a continuous signal is sampled at a rate too low to accurately...
• AlidadeA sighting device used in conjunction with a plane table or other surveying instruments to measure angles and...
• AlimentationThe process by which a glacier gains mass, primarily through the accumulation of snow and ice. This input of...
• Alisov's classification of climateA genetic climate classification system based on the geographic location and seasonal migration of...
• AlkalinityA measure of the capacity of water to neutralize acids, primarily due to the presence of bicarbonate...
• AlkanesA class of saturated hydrocarbons consisting only of carbon and hydrogen atoms joined by single bonds...
• AlkenesA class of unsaturated hydrocarbons containing at least one carbon-carbon double bond, with the general...
• Alkylperoxy radicalsHighly reactive chemical species formed in the atmosphere through the oxidation of volatile organic compounds...
• AlkynesA class of unsaturated hydrocarbons characterized by the presence of at least one carbon-carbon triple bond...
• Allard's lawA principle describing the propagation of light through the atmosphere, stating that the illuminance from a...
• AllerheiligenwindA specific wind phenomenon observed in parts of Central Europe, particularly in the Alpine regions, referring...
• All-hallown summerA period of unseasonably warm, calm, and dry weather that sometimes occurs in late autumn, typically around...
• AllobaricRelating to changes in atmospheric pressure over time, particularly those associated with the movement of...
• Allowed transitionsQuantum mechanical transitions between energy levels of atoms or molecules that obey specific selection...
• All-sky photometerAn instrument designed to measure the radiance of the entire sky dome, providing data on atmospheric aerosols...
• AlluvialRelating to or composed of alluvium, which is the sediment of clay, silt, sand, and gravel deposited by...
• Alluvial aquiferA body of permeable, unconsolidated sediment, primarily sand and gravel, deposited by rivers, that can store...
• AlluviumSediments deposited by erosional processes, usually by streams.
• All-weather airportAn airport equipped with advanced navigation aids, lighting systems, and air traffic control procedures that...
• AlmanacA publication containing a calendar of days, weeks, and months, along with astronomical data such as sunrise...
• Almeria-Oran frontA semi-permanent oceanic front located in the eastern Alboran Sea, extending between Almeria, Spain, and...
• AlmwindA local wind phenomenon observed in mountainous regions, particularly in the Alps, characterized by a warm...
• Along-slope Wind SystemA closed, thermally driven diurnal mountain wind circulation whose lower branch blows up or down the sloping...
• Along-slope wind systemsLocal wind patterns that develop due to differential heating or cooling of mountain slopes compared to the...
• Along-valley wind systemsLocal wind patterns that develop within valleys, primarily driven by pressure gradients created by...
• Along-valley windsAir currents that flow parallel to the orientation of a valley, driven by thermal differences between the...
• Aloup de ventA sudden, violent gust of wind, often localized and short-lived, that can occur without a broader change in...
• AlpenglowA reddish or pinkish glow observed on mountain peaks and high clouds around sunrise or sunset. This...
• Alpha rayA stream of alpha particles, which are helium nuclei (two protons and two neutrons), emitted during the...
• Alpine glacierA mass of ice that forms in mountainous regions, confined within valleys or cirques, and flows downslope...
• Alpine tundraA biome found at high altitudes above the treeline, characterized by cold temperatures, strong winds, and a...
• ALQDSAll Quadrants
• Alter shieldA device used to protect a precipitation gauge from wind effects, which can cause an underestimation of...
• Alternate airportAn airport designated in a flight plan where an aircraft may proceed if it becomes inadvisable to land at the...
• Alternate forecastA weather forecast prepared specifically for an airport designated as an alternate in a flight plan. This...
• Alternating unit tensorA mathematical object, also called the Levi-Civita symbol, used to simplify vector and tensor calculations in...
• ALTHOalthough
• Alti-electrographAn instrument designed to measure and record variations in atmospheric electric potential with altitude. This...
• AltigraphA recording altimeter that continuously measures and records atmospheric pressure, which is then converted to...
• AltimeterAn instrument used to measure altitude, primarily by sensing changes in atmospheric pressure. Most altimeters...
• Altimeter correctionsAdjustments applied to an indicated altitude reading from a pressure altimeter to compensate for deviations...
• Altimeter equationA mathematical relationship that describes the conversion of atmospheric pressure to altitude, based on the...
• Altimeter settingA pressure value used to calibrate a barometric altimeter so that it indicates the airport's elevation above...
• Altimeter-setting indicatorA precision aneroid barometer calibrated to display the local altimeter setting directly, rather than the...
• AltimetryThe science and technology of measuring altitude or elevation. In meteorology and aviation, it primarily...
• Altithermal periodA past climatic interval characterized by significantly warmer temperatures than the present, occurring...
• AltitudeThe vertical distance of an object or point in the atmosphere above a specified reference level, most...
• AltocumulusA mid-level cloud type characterized by white or grayish patches, sheets, or layers, composed of water...
• AltostratusA mid-level cloud type appearing as a gray or bluish-gray cloud sheet or layer, which is uniform in...
• Aluminum oxide humidity elementA sensor used to measure atmospheric humidity, consisting of an aluminum oxide layer that changes its...
• AmbientOf the surrounding area or environment.
• Ambient airThe surrounding outdoor air in a specific location, as it exists in its natural state. Its properties, such...
• Ambient pressureThe atmospheric pressure of the surrounding environment at a given location and time. It is the pressure...
• Ambient temperatureThe temperature of the surrounding air or environment at a specific location and time. It is the temperature...
• Ambiguity functionA mathematical tool used in radar and sonar signal processing to characterize the resolution of a waveform in...
• AMDAmend
• AmmoniaA colorless, alkaline gas (NH3) composed of nitrogen and hydrogen, present in the atmosphere in trace...
• AmmonificationThe biological process by which organic nitrogen compounds are converted into ammonia (NH3) or ammonium ions...
• Ammonium chlorideA white, crystalline salt with the chemical formula NH4Cl, formed from the reaction of ammonia and...
• Ammonium ionA positively charged polyatomic ion with the chemical formula NH4+. In the atmosphere, it forms when ammonia...
• Ammonium nitrateA chemical compound with the formula NH4NO3, formed in the atmosphere from the reaction of ammonia with...
• Ammonium sulfateA chemical compound with the formula (NH4)2SO4, which is a common component of atmospheric aerosols. It forms...
• Amorphous cloudsClouds that lack a distinct or well-defined shape, appearing as a shapeless mass in the sky. This formless...
• Amorphous frostA type of frost characterized by its lack of crystalline structure, appearing as a granular or powdery...
• Amorphous skyA sky condition where clouds are present but lack any discernible structure or distinct forms, appearing as a...
• AMOSAutomatic Meteorological Observing System
• Amount of precipitationThe total depth of liquid water that falls on a horizontal surface over a specified period, including both...
• AmphidromeA point in an ocean or sea where the tidal range is effectively zero, around which tidal waves rotate. These...
• AmplifierA device used to increase the strength of an analog signal
• AmplitudeThe maximum displacement or distance moved by a point on a vibrating body or wave measured from its...
• Amplitude modulationA technique for transmitting information by varying the amplitude of a carrier wave in proportion to the...
• Amplitude spectrumA graphical representation showing the amplitude of different frequency components present in a signal. In...
• Amplitude-modulated indicatorA display device that presents information by varying the brightness or intensity of a signal in proportion...
• AMS1. Air Mass - a body of air covering a relatively wide area and exhibiting horizontally uniform properties.
• AMTAmount
• AMVERAutomated Mutual Assistance Vessel Rescue System. A system operated by the U.S. Coast Guard which computes...
• AMVER/SEASA software program created by the National Weather Service intended to efficiently generate AMVER and VOS...
• AnabaticRelating to an upward-moving air current, typically occurring on sun-warmed slopes during the daytime. This...
• Anabatic windA local wind that flows uphill, driven by the differential heating of a mountain slope compared to the air at...
• AnabranchA diverging branch of a river which re-enters the main stream.
• Anadyr CurrentA cold, eastward-flowing ocean current in the Bering Sea, originating from the Bering Strait and flowing...
• Anaerobic conditionAn environmental state characterized by the complete absence of free molecular oxygen. In atmospheric...
• AnafrontA type of weather front where the warm air mass actively rises over the colder air mass, leading to...
• AnallobaricDescribing a wind that does not cross isobars, meaning it flows parallel to them. An anallobaric wind is...
• AnalogA past atmospheric or oceanic state that closely resembles a current or forecast state, used to infer future...
• Analog climate modelA method of climate modeling that uses historical climate data to find past periods with similar atmospheric...
• Analog methodA forecasting technique that involves identifying past weather situations that are similar to the current...
• Analog modelA forecasting model that operates by searching historical records for past atmospheric or oceanic states that...
• Analog signalA signal, such as voice, that varies in a continuous manner.
• Analogs, see Analog
• AnalogueA past atmospheric or oceanic state that closely resembles a current or forecast state, used to infer future...
• AnalysisA detailed map or chart representing the state of the atmosphere at a specific time, created by plotting and...
• Analysis of varianceA statistical method used to partition the observed variance in a particular variable into components...
• Analyzed chartA weather map that displays the current state of the atmosphere, derived from the objective analysis of...
• ANBURSAlphanumeric Backup Replacement System
• Anchor balloonA tethered balloon used to carry meteorological instruments aloft for atmospheric soundings or continuous...
• Anchor iceSubmerged ice that forms on the bed of a river or lake, or on objects in flowing water, when the water...
• Anchor ice damAn accumulation of anchor ice which acts as a dam and raises the water level.
• Anelastic approximationA simplification used in atmospheric and oceanic modeling that filters out sound waves by assuming a...
• AnemoclinometerAn instrument designed to measure both the speed and direction of wind, including its vertical component. It...
• AnemometerAn instrument used for measuring the speed of the wind.
• Anemometer levelThe standard height above the ground at which an anemometer is installed to measure wind speed for...
• AnemometryThe scientific field concerned with the measurement of wind speed and direction. It encompasses the...
• AnemoscopeA simple instrument that indicates the direction of the wind. Unlike a wind vane, which physically points...
• AnemovaneA single instrument that combines the functions of an anemometer and a wind vane, simultaneously measuring...
• AneroidRelating to a type of barometer that measures atmospheric pressure without the use of a liquid, such as...
• Aneroid barographA recording instrument that continuously measures and plots atmospheric pressure changes over time using an...
• Aneroid barometerAn instrument used to measure atmospheric pressure, consisting of a sealed, evacuated metal capsule that...
• Aneroid capsuleA small, flexible, evacuated metal chamber, typically made of beryllium copper or phosphor bronze, that forms...

888 of 10,816 terms in Meteorology and atmospheric science terminology (MLC-0110). Request the full dataset.