Meteorology and atmospheric science terminology · MLC-0110

Meteorology and atmospheric science terms: I (465)

• I and Q channelsThe in-phase (I) and quadrature (Q) components of a complex signal, used in radar and telecommunications to...
• Ibe windA strong local wind blowing through the Dzungarian Gate, the mountain pass on the border of China and...
• IceThe solid phase of water, forming when liquid water freezes at or below 0 degrees Celsius (32 degrees...
• Ice accretionThe process by which ice accumulates on surfaces, particularly on aircraft, structures, or vegetation, when...
• Ice ageA prolonged period of global cooling during which large areas of the Earth's surface are covered by glaciers...
• Ice apronA mass of snow and ice that clings to a steep wall, as on the headwall of a cirque or on a valley wall...
• Ice bandA distinct layer or stratum of ice within a larger body of snow or ice, such as a glacier or an ice sheet...
• Ice bands, see Ice band
• Ice bayAn indentation in the edge of an ice sheet or ice shelf, formed by local melting or by the movement of ice...
• Ice blinkA luminous appearance in the sky, typically a yellowish-white glare, observed over distant ice or snow fields...
• Ice boomIn hydrologic terms, a floating structure designed to retain ice.
• Ice breakupThe process by which a continuous sheet of ice, such as on a river, lake, or sea, fractures and disintegrates...
• Ice bridgeIn hydrologic terms, a continuous ice cover of limited size extending from shore to shore like a bridge.
• Ice capA dome-shaped mass of glacier ice that covers a highland area, obscuring the underlying topography. Its flow...
• Ice coverThe extent or fraction of a water surface, such as a sea, lake, or river, that is frozen. It is described by...
• Ice crustA hard layer of ice lying on top of snow, formed when meltwater or rain runs over the snow and freezes. It is...
• Ice crystalA small, solid particle of ice that forms in the atmosphere, typically at temperatures below freezing, and...
• Ice crystals, see Ice crystal
• Ice dayA meteorological day during which the maximum air temperature remains at or below 0 degrees Celsius (32...
• Ice desertA polar region characterized by extremely low temperatures, very little precipitation, and a permanent cover...
• Ice driftThe movement of sea ice that is not attached to the shoreline or grounded. This motion is driven by the...
• Ice edgeThe boundary between open water and an area of sea ice, which can be either compact or diffuse. This dynamic...
• Ice feathersA delicate, feathery pattern of frost composed of interlocking ice crystals that form on a cold surface...
• Ice fieldA large area of interconnected glaciers and ice caps that covers a mountainous region, but is not extensive...
• Ice flowThe movement of glacial ice, ice sheets, or ice shelves under the influence of gravity and internal...
• Ice flowersDelicate, intricate ice crystals that grow on the surface of thin, newly formed sea ice or lake ice...
• Ice fogA type of fog composed of tiny ice crystals suspended in the air, occurring at very low temperatures...
• Ice footA narrow fringe of ice that adheres to the coastline, typically found in polar and subpolar regions. It is...
• Ice forecastA prediction of future ice conditions, including the extent, concentration, thickness, and movement of sea...
• Ice formation on aircraftThe accumulation of ice on the external surfaces of an aircraft, occurring when supercooled water droplets in...
• Ice frontThe vertical seaward face of an ice shelf or of a glacier that ends in water, where the ice breaks off as...
• Ice gorgeIn hydrologic terms, the gorge or opening left in a jam after it has broken.
• Ice islandAn extremely large, tabular piece of floating ice that has calved from an Arctic ice shelf, such as those...
• Ice jamAn accumulation of broken ice pieces that obstructs the flow of a river or waterway. This phenomenon often...
• Ice keelThe downward projection of ice beneath a sea-ice pressure ridge, mirroring the sail that rises above the...
• Ice layerA distinct stratum of ice within a snowpack or on a surface, formed by the refreezing of meltwater or by...
• Ice limitThe maximum extent of sea ice observed in a particular region over a specified period, or the average...
• Ice mixing ratioThe ratio of the mass of ice particles to the mass of dry air in a given volume of atmosphere. This value is...
• Ice moundA localized elevation of ice on a surface, often formed by the accumulation of snow and ice or by the...
• Ice multiplicationA process that rapidly increases the number of ice crystals in a cloud far beyond the number of primary...
• Ice needleA thin, columnar type of ice crystal that forms in very cold, stable air masses, sometimes appearing to fall...
• Ice nuclei counterAn instrument designed to detect and quantify the concentration of ice nuclei in an air sample. These devices...
• Ice nucleusA microscopic particle in the atmosphere that acts as a site for the formation of an ice crystal. These...
• Ice pelletsPrecipitation consisting of small, translucent or transparent ice spheres, also known as sleet. These form...
• Ice plainA broad, nearly flat part of a fast-flowing ice stream or outlet glacier just upstream of its grounding line...
• Ice pointThe temperature at which pure water freezes at standard atmospheric pressure, defined as 0 degrees Celsius or...
• Ice poleThe point taken as the middle of the most heavily consolidated Arctic pack ice, located near 83 to 84 degrees...
• Ice prismsA form of precipitation consisting of unbranched, columnar ice crystals in the shape of needles, columns, or...
• Ice pushIn hydrologic terms, compression of an ice cover particularly at the front of a moving section of ice cover.
• Ice raftA coherent block of glacier ice carried along within an ice stream or an ice shelf, riding a little above its...
• Ice regime phaseOne of the successive stages in the seasonal ice history of a river, lake, or reservoir, such as first ice...
• Ice rindA thin, brittle, shiny crust of new ice formed on a quiet water surface, either by direct freezing or from...
• Ice riseA dome-shaped elevation of ice that is grounded on the seabed or land within an ice shelf. These features are...
• Ice runThe rapid movement of a large mass of ice, often broken into floes, within a body of water such as a river or...
• Ice shelfA thick, floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto...
• Ice shoveIn hydrologic terms, on-shore ice push caused by wind, and currents, changes in temperature, etcetera.
• Ice stormA winter storm characterized by freezing rain that coats outdoor surfaces with a layer of ice. This occurs...
• Ice storm warningThis product is issued by the National Weather Service when freezing rain produces a significant and possibly...
• Ice streamA region within an ice sheet or ice cap where ice flows considerably faster than the surrounding ice. These...
• Ice structureThe internal arrangement and characteristics of ice crystals within a larger body of ice, such as a glacier...
• Ice tongueA long, narrow projection of ice that extends from a glacier or ice sheet into a body of water, such as a...
• Ice twitchIn hydrologic terms, downstream movement of a small section of an ice cover. Ice twitches occur suddenly and...
• Ice-accretion indicatorA device or method used to detect and measure the accumulation of ice on a surface. These indicators can...
• IcebergA large mass of freshwater ice that has broken away from a glacier or ice shelf and drifts in open water...
• Ice-bulb temperatureThe temperature indicated by a thermometer whose bulb is covered with a thin layer of ice, exposed to a...
• Ice-crystal cloudA cloud composed predominantly or entirely of ice crystals rather than liquid water droplets. These clouds...
• Ice-crystal hazeAn atmospheric condition characterized by reduced visibility due to a suspension of numerous minute ice...
• Iced firnFirn that has undergone further densification and transformation due to the presence of meltwater that...
• IcefallA section of a glacier where the ice flows rapidly over a steep incline or irregular terrain, resulting in a...
• Icelandic lowA persistent, semi-permanent center of low atmospheric pressure located near Iceland and southern Greenland...
• IcicleA tapering, pointed spike of ice formed when water drips slowly and freezes as it falls or runs off an object...
• IcingThe accumulation of ice on aircraft surfaces, structures, or instruments when flying through supercooled...
• Icing intensityA measure of the rate and severity of ice accumulation on aircraft surfaces or other structures exposed to...
• Icing levelThe lowest altitude over a given location where icing conditions can affect an airplane, which requires cloud...
• Icing-rate meterAn instrument designed to measure the rate at which ice accumulates on a surface, particularly on aircraft or...
• Ideal fluidA hypothetical fluid characterized by zero viscosity and incompressibility, meaning it offers no resistance...
• Ideal gasA theoretical gas composed of randomly moving point particles that interact only through elastic collisions...
• Ideal gas lawsThe thermodynamic laws applying to perfect gases.
• Identical twin integrationsA method used in numerical weather prediction and climate modeling to assess the predictability of the...
• IF signalAn intermediate frequency signal, which is the result of mixing an incoming radio frequency signal with a...
• IFFAn abbreviation for Identification Friend or Foe, an electronic system used by military aircraft and air...
• IFRInstrument Flight Rules, a set of regulations governing flight under conditions where visual reference to the...
• IFR terminal minimumsThe lowest weather conditions, specifically ceiling and visibility, under which an aircraft can legally...
• IFR weatherConditions of low cloud base, reduced visibility, or both under which flights must be conducted by instrument...
• IF-THEN ruleA conditional statement used in expert systems, fuzzy logic, and decision-making processes, where a specific...
• IlluminanceThe measure of the total amount of light, or luminous flux, falling onto a surface per unit of area. It...
• IlluminationThe process or state of being lit by light, referring to the application of light to an object or area to...
• Image enhancementThe process of manipulating a digital image to improve its visual quality or to highlight specific features...
• Image processingThe use of computer algorithms to perform operations on digital images, often to extract information, enhance...
• ImbibitionThe process by which a substance absorbs a liquid, causing it to swell, often observed in porous materials...
• Immiscible displacementThe process by which one fluid pushes out another from a porous medium when the two fluids are insoluble in...
• ImpactorA device used to collect airborne particulate matter by accelerating the air stream through a nozzle and...
• ImpermeableMaterial that does not permit fluids to pass through it.
• ImperviousIn hydrologic terms, the ability to repel water, or not let water infiltrate
• ImpingerA type of air sampling device that collects airborne contaminants by drawing air through a liquid medium...
• IMPLImpulse- Alternate term for Upper Level System and Shortwave; a general term for any large-scale or mesoscale...
• Implicit time differenceA numerical method for solving time-dependent differential equations where the future state of the system is...
• ImportIn hydrologic terms, water piped or channeled into an area
• Improved TIROS Operational SystemA series of United States polar-orbiting weather satellites, NOAA-1 through NOAA-5, launched between 1970 and...
• IMPTImportant
• Impulse(abbrev. IMPL) Alternate term for Upper Level System and Shortwave; a general term for any large-scale or...
• In HgInches of Mercury
• InaccuracyThe degree to which a measured or calculated value deviates from the true value of the quantity being...
• Inactive frontA frontal boundary that has lost much of its original temperature or moisture contrast, resulting in little...
• Inactive storage capacityIn hydrologic terms, the portion of capacity below which the reservoir is not normally drawn, and which is...
• Inadvertent climate modificationUnintentional changes to the Earth's climate system resulting from human activities, such as the emission of...
• Inadvertent cloud modificationUnintentional alterations to cloud properties or formation processes caused by human activities. This can...
• Inadvertent weather modificationUnintended changes in local or regional weather patterns resulting from human activities. This encompasses...
• Inch of mercuryA unit of pressure commonly used in meteorology, particularly in the United States, to express atmospheric...
• Inch-DegreesThe product of rainfall (in inches) multiplied by the temperature (in degrees Fahrenheit) above freezing...
• Inches of mercury(or in Hg) Unit of atmospheric pressure used in the United States. The name comes from the use of mercurial...
• Inches of runoffIn hydrologic terms, the volume of water from runoff of a given depth over the entire drainage
• InclinationThe angle or slope of a physical quantity or surface relative to a reference plane, often the horizontal or...
• Inclination of the axis of a cycloneThe departure from vertical of the central axis of a cyclonic circulation system as it extends upward through...
• Inclination of the axis of an anticycloneThe tilt of an anticyclone's axis of maximum pressure as it is followed upward through the atmosphere. In...
• Inclination of the windThe angle at which the wind blows across isobars, deviating from a path parallel to them. In the free...
• In-cloud lightning(abbrev. IC) Lightning that takes place within the cloud.
• Incoherent echoA radar echo formed by summing the returns from many randomly placed scatterers, such as raindrops, whose...
• Incoherent scatter radarA radar that probes the ionosphere by detecting the extremely weak scattering of its megawatt-level VHF or...
• Incoherent scatteringScattering by a collection of particles in which the waves scattered from different particles have random...
• IncompressibilityA property of a fluid where its density remains constant despite changes in pressure. In atmospheric science...
• Incompressible fluidA fluid whose density remains constant regardless of changes in pressure. In atmospheric science, air is...
• INCRIncrease
• IncusThe anvil-shaped top of a mature cumulonimbus cloud, formed when the rising air currents reach the tropopause...
• INDCIndicate
• Indefinite ceilingA meteorological condition where the vertical visibility is restricted due to obscuring phenomena, such as...
• IndependenceA statistical property where the occurrence of one event does not affect the probability of another event. In...
• Independent pixel approximationA simplification used in remote sensing and radiative transfer models where each pixel in an image is treated...
• Independent variableA variable in an experiment or model that is manipulated or changed by the researcher, and whose effect on...
• Independently distributedA property of random variables whose joint probability distribution equals the product of their individual...
• IndexA numerical value or ratio derived from meteorological observations or calculations, used to quantify a...
• Index correctionAn adjustment applied to a reading from a meteorological instrument to account for a systematic error in its...
• Index cycleA quasi-periodic fluctuation in the strength and pattern of the atmospheric circulation, particularly in the...
• Index errorA systematic error in an instrument's reading that results from a constant offset or misalignment of its...
• Index of aridityA numerical measure of how dry a climate is, built from precipitation and temperature or from precipitation...
• Index of continentalityA numerical value that quantifies the degree to which a location's climate is influenced by its distance from...
• Index of wetnessThe ratio of the precipitation measured in a particular year to the long-term mean annual precipitation at...
• Indian Deep WaterA deep water mass of the equatorial and northern Indian Ocean, found roughly between 1500 and 3800 meters...
• Indian equatorial jetA strong eastward surface current confined to a narrow band along the Indian Ocean equator, also called the...
• Indian National Satellite SystemA series of multi-purpose geostationary satellites operated by the Indian Space Research Organisation (ISRO)...
• Indian spring low waterA low-water chart datum set below mean sea level by the sum of the amplitudes of the tidal constituents M2...
• Indian summerA period of unseasonably warm, dry, and hazy weather that occurs in mid-to-late autumn, following a period of...
• Indicated airspeedThe speed of an aircraft as shown on its airspeed indicator, directly reflecting the dynamic pressure...
• Indicated altitudeThe altitude shown on an aircraft's pressure altimeter for whatever reference pressure is set on its scale...
• IndicatorA measurable variable or phenomenon that provides information about the state or trend of a system, often...
• Indicator functionA mathematical function that takes a value of one if a certain condition is met and zero otherwise. In...
• Indirect cellA closed meridional circulation in which relatively cold air rises and relatively warm air sinks, the reverse...
• Indirect circulationAn atmospheric circulation where the air parcels move in a direction opposite to what would be expected from...
• Indirect hitGenerally refers to locations that do not experience a direct hit from a tropical cyclone, but do experience...
• Individual derivativeThe rate of change of a property of a fluid parcel as it moves through space and time. It accounts for both...
• Indonesian ThroughflowThe flow of warm, fresh surface water from the Pacific Ocean to the Indian Ocean through the straits and...
• InductionA cloud electrification process in which a falling hydrometeor, such as graupel, is polarized by the ambient...
• Induction charging mechanismA thunderstorm charge-separation mechanism in which graupel or other falling particles are polarized by the...
• Induction icingThe accumulation of ice in the air intake system of an aircraft engine, restricting airflow and causing loss...
• Industrial climatologyA specialized branch of applied climatology that focuses on the analysis and application of climate data for...
• Industrial consumptionThe quantity of water consumed in a municipality or district for mechanical, trade, and manufacturing...
• Industrial meteorologyThe application of meteorological knowledge and forecasting techniques to support the operations and...
• Inertia waveA wave in a rotating fluid whose restoring force is the Coriolis force rather than buoyancy. In a uniformly...
• Inertial circleA circular path followed by a fluid parcel in a rotating system when it is subject only to the Coriolis...
• Inertial coordinate systemA reference frame in which Newton's laws of motion hold true without the introduction of fictitious forces...
• Inertial currentAn ocean current that results from an initial impulse, such as a strong wind event, and then continues to...
• Inertial flowFluid motion where the dominant forces are inertia and the Coriolis force, with pressure gradients and...
• Inertial forceAn apparent force that must be added to Newton's laws to describe motion relative to an accelerating or...
• Inertial forecastA simple type of weather forecast that assumes future conditions will be the same as current conditions...
• Inertial instabilityA type of atmospheric or oceanic instability that occurs when the absolute angular momentum of a fluid parcel...
• Inertial lagThe delay in the response of a measuring instrument to a change in the quantity it is designed to measure...
• Inertial oscillationA periodic motion of a fluid parcel in a rotating system, driven solely by the Coriolis force, resulting in a...
• Inertial periodThe time it takes for a fluid parcel to complete one full rotation in an inertial oscillation, driven solely...
• Inertial rangeA range of scales in a turbulent fluid flow where energy is transferred from larger eddies to smaller eddies...
• Inertial reference frameA coordinate system in which an object at rest remains at rest and an object in motion continues in motion...
• Inertial stabilityThe resistance of an atmospheric or oceanic fluid parcel to horizontal displacement, arising from the...
• Inertial sublayerThe region within the atmospheric boundary layer, immediately above the viscous sublayer, where turbulent...
• Inertial subrangeA specific portion of the inertial range in turbulent flows where the energy cascade from large to small...
• Inertial waveA wave motion in a rotating fluid for which the Coriolis force supplies the restoring effect, so it needs no...
• Inertial-convective subrangeThe range of scales in turbulent flow over which the variance of a scalar such as temperature or humidity is...
• Inertial-diffusive subrangeA range of scales in turbulent flow where the transport of scalar quantities, such as temperature or...
• Inertio-gravity waveA type of atmospheric or oceanic wave influenced by both the Coriolis force and buoyancy forces, which act to...
• InferenceThe process of deriving conclusions or making predictions based on available data, observations, or...
• Inference engineA component of an expert system or artificial intelligence system that applies logical rules and facts to...
• Inferior mirageAn optical phenomenon where distant objects appear to be displaced downwards and inverted, as if reflected in...
• InfiltrationThe process by which water on the ground surface enters the soil. This movement occurs through pores and...
• Infiltration capacityThe maximum rate at which water can penetrate the soil surface under specific conditions, typically when the...
• Infiltration coefficientA dimensionless parameter that quantifies the rate at which water penetrates the soil surface. It represents...
• Infiltration galleryA subsurface structure designed to collect groundwater, consisting of one or more horizontal conduits placed...
• Infiltration indexAn average infiltration rate over a storm, derived from the rainfall record and the measured direct runoff...
• Infiltration rateThe speed at which water enters the soil from the surface, usually expressed in units of depth per unit time...
• Infiltration routingA procedure for calculating how water moves down through soil that is not saturated. It follows the wetting...
• Infiltration wellA vertical shaft or bore designed to introduce surface water into an aquifer, replenishing groundwater...
• InfiltrometerA device used to measure the rate at which water penetrates the soil surface. It typically consists of a...
• InflowThe flow of air into a weather system, storm, or specific region of the atmosphere. In a thunderstorm, inflow...
• Inflow bandsBands of low clouds, arranged parallel to the low-level winds and moving into or toward a thunderstorm. They...
• Inflow jetsLocal jets of air near the ground flowing inward toward the base of a tornado.
• Inflow notchA radar signature characterized by an indentation in the reflectivity pattern on the inflow side of the...
• Inflow stingerA beaver tail cloud with a stinger-like shape.
• Influent seepageThe process where water from a surface body, such as a river or lake, moves downward into the underlying...
• Influent streamIn hydrologic terms, any watercourse in which all, or a portion of the surface water flows back into the...
• Infralateral tangent arcsRare optical phenomena that appear as bright, colored arcs tangent to the 46-degree halo, below the sun or...
• InfraredElectromagnetic radiation with wavelengths longer than visible light but shorter than microwaves. This...
• Infrared imageA visual representation created by detecting and displaying infrared radiation emitted or reflected by...
• Infrared Interferometer SpectrometerA satellite-borne instrument that measures the spectrum of infrared radiation emitted by the Earth's surface...
• Infrared radiationElectromagnetic radiation with wavelengths longer than visible light but shorter than microwaves, generally...
• Infrared radiometryThe measurement of infrared radiation emitted or reflected by objects and surfaces. This technique is used in...
• Infrared satellite imageryThis satellite imagery senses surface and cloud top temperatures by measuring the wavelength of...
• Infrared spectrometerAn instrument designed to measure the intensity of infrared radiation as a function of wavelength. In...
• Infrared spectroscopyA technique that analyzes the interaction of infrared radiation with matter to identify and quantify...
• InfrasonicDescribing sound waves with frequencies below the lower limit of human audibility, typically less than 20...
• Infrasonic observatoryA facility equipped with specialized microphones and sensors designed to detect and analyze sound waves with...
• InfrasoundSound waves with frequencies below the range of human hearing, generally less than 20 hertz. These waves can...
• IngestingThe receipt of incoming data by a computer system, such as observations, model output and climate data taken...
• Initial conditionThe complete set of atmospheric data describing the state of the atmosphere at the starting time of a...
• Initial detentionIn hydrologic terms, the volume of water on the ground, either in depressions or in transit, at the time...
• Initial rainfallThe first rain of a storm, which is taken up by interception on vegetation and by storage in surface...
• InitializationThe adjustment of analyzed fields before a numerical weather prediction run so that wind, pressure and...
• Initial-value problemA mathematical problem where the solution of a differential equation is sought given the state of the system...
• Injection temperatureThe temperature of seawater drawn into a ship's engine cooling or condenser intake, read in the engine room...
• Inland freshwater wetlandsIn hydrologic terms, swamps, marshes, and bogs found inland beyond the coastal saltwater wetlands.
• Inland iceA large mass of glacial ice that covers an extensive land area, distinct from mountain glaciers or sea ice...
• Inland sea breezeA localized wind system that develops over land, driven by differential heating between adjacent land...
• INLDInland
• Inner layerThe region of the atmospheric boundary layer closest to the Earth's surface, where turbulent eddies are...
• InputData, information, or energy supplied to a system or model for processing or analysis. In atmospheric...
• INSAn Inertial Navigation System, a self-contained unit of accelerometers and gyroscopes that tracks position...
• InsolationThe amount of solar radiation received by a surface per unit area over a given period. This energy input...
• Insolation durationThe total length of time during a day, month, or year that a specific location receives direct sunlight. This...
• Inspectional analysisA method of obtaining the dimensionless similarity parameters of a physical problem by writing its governing...
• InstabilityA condition in the atmosphere where a parcel of air, if displaced vertically, tends to accelerate away from...
• Instability chartA synoptic chart on which a stability or instability index is plotted and analyzed over a region, showing...
• Instability lineAny non-frontal line or narrow band of convective activity, such as a row of showers or thunderstorms in...
• Instantaneous field of viewThe specific area or solid angle that a sensor or detector observes at a single moment in time, determining...
• Instantaneous unit hydrographA theoretical hydrograph representing the direct runoff response of a watershed to an instantaneous input of...
• INSTBYInstability- The tendency for air parcels to accelerate when they are displaced from their original position...
• Instrument correctionAn adjustment applied to raw measurements obtained from a meteorological instrument to account for known...
• Instrument errorThe deviation of a measurement from the true value due to imperfections or limitations inherent in the...
• Instrument exposureThe placement and positioning of a meteorological instrument relative to its immediate surroundings, which...
• Instrument flightA flight conducted solely by reference to the instruments in the cockpit, without reliance on visual cues...
• Instrument flight rulesA set of regulations governing aircraft operations when visual reference to the ground or horizon is not...
• Instrument shelterA standardized enclosure designed to protect meteorological instruments, such as thermometers and...
• Instrument weatherAtmospheric conditions that necessitate the use of aircraft instruments for navigation and control due to...
• Insulated streamA stream that flows above the water table and is separated from the underlying groundwater by an unsaturated...
• InsulationA material or layer that has low thermal conductivity and so reduces the transfer of heat between two...
• Intangible flood damageIn hydrologic terms, estimates of the damage done by disruption of business, danger to health, shock, and...
• Integral depth scaleAn effective depth of a layer, found by integrating the vertical profile of a quantity such as temperature...
• Integral length scalesMeasures of the characteristic sizes of the largest turbulent eddies within a fluid flow. These scales...
• Integration methodA stream-gauging technique that estimates the mean velocity or mean sediment concentration on a vertical by...
• IntensityA measure of the strength or severity of a meteorological phenomenon, quantified using a specific scale or...
• Intensity modulationA technique where the amplitude or brightness of a signal is varied in proportion to the information being...
• Intensity-duration-frequency curveA graphical representation showing the relationship between rainfall intensity, duration, and return period...
• Intensity-modulated indicatorA display device that uses variations in brightness or color to represent the strength or magnitude of a...
• Intensive quantityA physical property of a system that does not depend on the amount of substance or the size of the system...
• Interactive image processingThe manipulation and analysis of digital images by a human operator in real-time, often used in meteorology...
• Interbasin transferIn hydrologic terms, the physical transfer of water from one watershed to another.
• InterceptionThe process by which precipitation is caught and held by vegetation surfaces before reaching the ground...
• Interception storage requirementsIn hydrologic terms, water caught by plants at the onset of a rainstorm. This must be met before rainfall...
• InterceptometerAn instrument or experimental setup designed to measure the amount of precipitation intercepted by a plant...
• Interdiurnal variationThe change in a meteorological variable, such as temperature or pressure, from one day to the next at a...
• InterfaceA boundary surface between two distinct phases or regions, such as between air and water, or between two...
• Interfacial tensionThe force per unit length existing at the boundary between two immiscible fluids, such as air and water, or...
• InterferenceThe superposition of two or more waves, giving a combined pattern in which the amplitudes reinforce where the...
• Interference regionA spatial area where two or more wave patterns overlap, resulting in a combined wave that exhibits either...
• InterferometerAn instrument that uses the principle of wave interference to make precise measurements of physical...
• InterferometryA technique that uses the interference of waves, typically electromagnetic waves, to extract information...
• InterflowThe lateral movement of water through the unsaturated zone above the water table, typically occurring as...
• InterglacialA geological period of warmer global temperatures and retreating glaciers that occurs between two glacial...
• Interglacial phaseA relatively warm interval within a larger ice age characterized by significantly reduced global ice volume...
• InterleavingThe vertical stacking of thin, alternating layers of water with different properties, such as temperature and...
• Intermediate ionA charged nanometer-sized atmospheric particle with an electrical mobility between that of small cluster ions...
• Intermediate standard timesThe synoptic observation hours of 0300, 0900, 1500 and 2100 UTC, which fall midway between the main standard...
• Intermediate synoptic timesThe times of 0300, 0900, 1500, and 2100 UTC.
• Intermediate waterA layer of ocean water found between the surface mixed layer and the deep water, characterized by distinct...
• IntermittencyThe characteristic of a time series or spatial field where periods of activity or high variability are...
• Intermittent streamA stream or river that flows only during certain times of the year, typically after periods of rainfall or...
• Intermonthly variationThe change in a meteorological variable, such as temperature or precipitation, from one month to the next at...
• Internal boundary layerA layer that develops within the atmospheric boundary layer when air flows from one surface type to another...
• Internal energyThe total energy contained within a thermodynamic system, comprising the kinetic and potential energies of...
• Internal gravity waveA wave that propagates within a fluid medium, such as the atmosphere or ocean, rather than on its surface...
• Internal tidesInternal gravity waves generated within a stratified body of water at tidal frequencies. They are created...
• Internal water circulationThe part of the water cycle that stays within one land area: water evaporates or is transpired from the...
• Internal waveA wave that propagates within a fluid medium where density varies with depth, with buoyancy acting as the...
• International candleA former unit of luminous intensity fixed in 1909 by agreement among the national standards laboratories of...
• International date lineThe line of longitude located at 180 degrees East or West (with a few local deviations) where the date...
• International Geomagnetic Reference FieldA standard mathematical description of the Earth's main magnetic field, representing the large-scale field...
• International Pyrheliometric ScaleA former international reference for measuring direct solar irradiance, introduced in 1956 to reconcile the...
• International Satellite Cloud Climatology ProjectA global research effort initiated in 1982 to collect and analyze satellite radiance data for the study of...
• International standard atmosphereA theoretical model of the Earth's atmosphere that defines average atmospheric conditions, including...
• International synoptic codeA standardized numerical code used for transmitting meteorological observations from surface stations and...
• International synoptic surface observation codeA standardized numerical code used globally for transmitting meteorological observations from surface weather...
• International System of UnitsThe modern form of the metric system, comprising a coherent system of units of measurement built upon seven...
• International Table calorieA specific definition of the calorie, a unit of energy, established by the International Steam Table...
• International UnitsA set of electrical units for current and resistance adopted at a congress held in Chicago in 1893, in which...
• Interplanetary dustMicroscopic particles of solid matter, typically ranging from nanometers to hundreds of micrometers in size...
• Interplanetary magnetic fieldThe magnetic field that permeates the solar system, originating from the Sun's corona and carried outward by...
• InterpluvialA relatively warm and dry period occurring between two pluvial periods, which are characterized by increased...
• InterpolateTo estimate a value within an interval between two known values. This technique is sometimes used with...
• InterpolationA mathematical technique used to estimate values of a function or variable at unobserved locations or times...
• Interpulse periodThe time interval between the transmission of consecutive pulses from a radar system, also known as the pulse...
• Interrupted streamA stream whose channel has some reaches that carry water all year and others that run dry for part of the...
• InterstadialA relatively warm phase of a glacial period, characterized by a temporary retreat of ice sheets and glaciers...
• Interstellar dustMicroscopic solid particles found in the space between stars, composed primarily of silicates, carbonaceous...
• IntersticeA small, narrow space or gap between particles, objects, or layers within a substance or structure. In...
• Intertropical convergence zoneA narrow zone near the equator where the trade winds from the Northern and Southern Hemispheres converge...
• Intertropical frontA narrow zone where the trade winds of the Northern and Southern Hemispheres converge, characterized by...
• IntortusA species of cirrus cloud characterized by irregularly entangled or twisted filaments, giving the cloud a...
• Intracloud flashA type of lightning discharge that occurs entirely within a single cloud, without striking the ground or...
• Intraseasonal oscillationOscillation with variability on a timescale less than a season. One example is the Madden-Julian Oscillation.
• Intrinsic permeabilityA measure of the ability of a porous medium to transmit fluids, independent of the fluid's properties. It...
• Intrinsic wave frequencyThe frequency of a wave as observed from a reference frame that is moving with the mean flow of the medium in...
• INTSIntense
• INTSFYIntensify
• INTSTIntensity
• InundationThe process of covering normally dry areas with flood waters.
• Invasion of airThe advection of an air mass with distinct thermal and moisture properties into a region previously occupied...
• Inventories of anthropogenic pollutantsSystematic compilations of the amounts of pollutants emitted into the atmosphere from human activities over a...
• InvernaA southerly wind that blows up Lake Maggiore in northern Italy during the afternoon, as the warmed plain...
• Inverse-square lawA principle stating that the intensity of a physical quantity emanating from a point source decreases in...
• InversionAn atmospheric condition where temperature increases with altitude, contrary to the typical decrease with...
• Inversion of rainfallA meteorological phenomenon where precipitation amounts increase with altitude up to a certain level, then...
• Inverted barometer effectThe response of sea level to changes in atmospheric pressure, where a decrease in atmospheric pressure leads...
• Inverted troughA trough of low pressure whose axis extends poleward from a low-pressure center, so that its isobars form an...
• Inviscid fluidA theoretical fluid that has no viscosity, meaning it offers no resistance to shear stress or flow. While no...
• INVOFIn the vicinity of
• INVRNInversion- Generally, a departure from the usual increase or decrease in an atmospheric property with...
• IonAn atom or molecule that has acquired an electrical charge by gaining or losing one or more electrons. In the...
• Ion chromatographyA laboratory technique used to separate and quantify ions in a solution. It involves passing a liquid sample...
• Ion cloudA patch of unusually dense ionization within one of the regular regions of the ionosphere. Such patches occur...
• Ion counterAn instrument designed to measure the concentration of atmospheric ions, both positive and negative. It...
• Ion densityThe number of ions per unit volume in a given region of the atmosphere. This quantity can refer to either...
• Ion mean lifeThe average time an ion exists in a particular atmospheric layer before it is removed by recombination with...
• Ion mobilityThe speed at which an ion moves through a gas or liquid under the influence of an electric field, normalized...
• Ion pairA positively charged ion and a negatively charged electron or ion that are created simultaneously from a...
• Ion-capture theoryA hypothesis explaining the electrification of clouds and precipitation, proposing that hydrometeors become...
• Ionic conductionThe movement of electrical charge through a medium by the migration of ions. In the Earth's atmosphere...
• IonizationThe process by which an atom or molecule acquires a net electrical charge by gaining or losing electrons. In...
• Ionization chamberA radiation detector that measures the amount of ionization produced in a gas by incident radiation. It...
• Ionization potentialThe minimum energy required to remove an electron from an atom or molecule in its gaseous state, forming a...
• Ionizing radiationAny type of radiation that carries enough energy to remove electrons from atoms or molecules, thereby...
• IonogramA graphical record produced by an ionosonde, showing the virtual height of ionospheric layers as a function...
• IonosondeA radar-like instrument used to probe the ionosphere by transmitting radio waves vertically upwards and...
• IonosphereThe region of the upper atmosphere, extending from about 60 to 1,000 kilometers in altitude, where solar...
• Ionospheric potentialThe electrical potential difference between the ionosphere and the Earth's surface, typically around 250 to...
• Ionospheric radarA type of radar system specifically designed to study the ionosphere by transmitting radio waves and...
• Ionospheric recorderAn instrument, also known as an ionosonde, that transmits radio pulses vertically into the ionosphere and...
• Ionospheric stormA disturbance of the ionosphere driven by a geomagnetic storm, in which electron density departs strongly...
• Ionospheric tidesPeriodic oscillations in the ionosphere's parameters, such as electron density, temperature, and winds...
• Ionospheric troughA region in the ionosphere characterized by significantly lower electron density compared to surrounding...
• IPIce pellets (sleet). See "PL"
• IPVImprove
• IRInfrared radiation, a portion of the electromagnetic spectrum with wavelengths longer than visible light but...
• IridescenceBrilliant spots or borders of colors in clouds, usually red and green, caused by diffraction of light by...
• Iridescent cloudsClouds that exhibit brilliant and varied colors, resembling mother-of-pearl, due to the diffraction of...
• IrisationThe display of colors in clouds, similar to those seen in soap bubbles or oil slicks, caused by the...
• IrradianceThe radiant flux incident on a surface per unit area, representing the power of electromagnetic radiation...
• IrradiationThe process of exposing an object or surface to radiation, particularly electromagnetic radiation such as...
• Irregular crystalA type of ice crystal that lacks a distinct, symmetrical geometric shape, often forming under complex...
• Irreversible processA thermodynamic process that cannot be reversed to its initial state without leaving some change in the...
• IrrigationThe artificial application of water to land to assist in the growth of agricultural crops, maintain...
• Irrigation requirementIn hydrologic terms, the quantity of water, exclusive of precipitation, that is required for crop production...
• Irrigation return flowWater that has been applied to agricultural fields for irrigation and subsequently drains from the fields...
• IrrotationalDescribing a fluid flow where the curl of the velocity field is zero, indicating an absence of local rotation...
• Isabnormal lineA line on a map or chart that connects points having an equal deviation from the long-term average or normal...
• IsallobarA line on a weather map connecting points of equal atmospheric pressure tendency, indicating areas where...
• IsallobaricRelating to lines of equal pressure tendency, which depict areas of equal atmospheric pressure change over a...
• Isallobaric chartA weather map that displays lines of equal pressure tendency, known as isallobars. These charts illustrate...
• Isallobaric windA component of the ageostrophic wind that arises where the pressure tendency varies horizontally, directed...
• Isallohypsic windThe ageostrophic wind component that arises from horizontal variations in the height tendency of a...
• IsallothermA line on a weather map connecting points of equal temperature change over a specific time interval...
• IsanabatA line on a chart joining points of equal vertical component of wind velocity. The isanabat for zero vertical...
• IsanakatabarA line on a weather map connecting points with the same change in surface pressure over a stated time...
• Isanomalous lineA line on a map connecting points of equal anomaly for a meteorological element, meaning equal deviation from...
• IsanomalyA line on a map connecting points of equal anomaly for a specific meteorological variable, where the anomaly...
• Isanthesic lineA line on a map joining places where a plant species begins flowering on the same date, used in...
• IsentropeA line on a thermodynamic diagram or a surface in three-dimensional space connecting points of equal...
• IsentropicDescribing a process or state in which the entropy of a parcel of air remains constant, implying that no heat...
• Isentropic analysisA method of analyzing atmospheric data by plotting meteorological variables on surfaces of constant potential...
• Isentropic chartA weather map that displays meteorological variables, such as pressure, wind speed, and moisture, on a...
• Isentropic liftLifting of air that is traveling along an upward-sloping isentropic surface.
• Isentropic mixingThe process by which air parcels exchange properties along surfaces of constant potential temperature. This...
• Isentropic surfaceA surface in the atmosphere on which potential temperature is constant. In adiabatic, frictionless flow air...
• Isentropic thickness chartA chart showing the vertical distance between two chosen isentropic surfaces, expressed in geometric or...
• Isentropic vertical coordinateA vertical coordinate system where surfaces of constant potential temperature (isentropes) are used as the...
• Isentropic weight chartA chart showing how far apart two chosen isentropic surfaces lie in pressure, a quantity proportional to the...
• IsobarA line on a weather map or chart connecting points of equal atmospheric pressure at a given time or averaged...
• IsobaricRelating to or describing a process or system that occurs at constant atmospheric pressure. In...
• Isobaric analysisThe meteorological practice of analyzing and displaying atmospheric variables on surfaces of constant...
• Isobaric chartA meteorological chart that displays atmospheric conditions on a surface of constant pressure. These charts...
• Isobaric contour chartA weather map that displays the height of a specific constant-pressure surface above sea level. Lines on the...
• Isobaric divergenceThe horizontal divergence of the wind evaluated on a surface of constant pressure, the rate at which air...
• Isobaric mixingThe process of mixing air parcels that occurs at a constant atmospheric pressure. This type of mixing can...
• Isobaric processAny thermodynamic change of state of a system that takes a place at constant pressure.
• Isobaric surfaceA surface within the atmosphere where the atmospheric pressure is constant. These surfaces are not perfectly...
• Isobaric thickness chartA map displaying the vertical distance, or thickness, between two specified isobaric surfaces, which is...
• Isobaric tubeA tube-shaped parcel of air whose walls are formed by a pair of constant-pressure surfaces and a pair of...
• Isobaric vorticityThe component of atmospheric vorticity calculated on an isobaric surface, representing the local rotation of...
• Isobaric-isosteric solenoidA tube bounded by two adjacent isobaric surfaces and two adjacent isosteric surfaces drawn at unit intervals...
• IsobathA line on a chart joining points of equal water depth below the surface of a sea or lake, the underwater...
• IsobathythermA line or surface joining points in a lake or ocean where a chosen temperature lies at the same depth, so...
• IsobrontA line on a weather map connecting points where a thunderstorm was first heard or observed at the same time...
• IsoceraunicA line on a map connecting points that have the same average number of thunderstorm days over a given period...
• Isoceraunic lineA line drawn on a map connecting geographical points that experience an equal number of thunderstorm days per...
• IsochasmA line on a map connecting points that experience the aurora borealis or aurora australis with the same...
• IsochoricRelating to a thermodynamic process that occurs at a constant specific volume. In atmospheric science, an...
• IsochroneA line on a map or chart connecting points where a particular meteorological phenomenon or event occurs at...
• IsoclineA line connecting points of equal inclination or slope. In geomagnetism an isocline joins places with the...
• Isoclinic lineA line on a map connecting points on the Earth's surface that have the same magnetic inclination or dip...
• iso-DA line on a weather chart connecting points of equal D-value. The D-value is the difference between the true...
• IsodopA contour of constant Doppler velocity values.
• IsodrosothermA line on a weather map or chart that connects points having an equal dew point temperature. Isodrosotherms...
• IsodynamicRelating to a line on a map that connects points of equal intensity of a force field, particularly the...
• IsoechoA line on a weather radar display connecting points of equal radar reflectivity intensity. These lines...
• IsogeothermA line or surface within the Earth connecting points of equal temperature. In atmospheric science, the term...
• IsogonA line on a weather map connecting points of equal wind direction. Isogons are used to analyze the flow of...
• Isogonic lineA line drawn on a map or chart connecting points of equal magnetic declination for a specific epoch. Magnetic...
• IsogramA line on a chart or map connecting points where a specific variable has a constant value. Isograms are used...
• IsohalineA line on a chart or a surface within a three-dimensional body of water that connects points having equal...
• IsoheightSame as a contour depicting vertical height of some surface above a datum plane.
• IsohelA line on a map connecting points that receive an equal amount of sunshine during a given period. These lines...
• IsohumeA line on a weather map or chart that connects points of equal relative humidity. Isohumes depict the spatial...
• IsohyetA line on a map connecting points that have received an equal amount of precipitation over a specific period...
• Isohyetal mapA geographical representation that displays lines connecting points of equal precipitation accumulation over...
• IsohypsicDescribing a line of constant geopotential height on a constant pressure surface. These lines are analogous...
• IsokineticRelating to a condition in fluid sampling where the velocity of the fluid entering the collection nozzle is...
• Isokinetic samplingA method of collecting a representative sample of particulate matter from a moving gas stream, where the...
• ISOLIsolate(d)
• IsolatedA National Weather Service convective precipitation descriptor for a 10 percent chance of measurable...
• Isolated systemA thermodynamic system that exchanges neither matter nor energy with its surroundings. This theoretical...
• ISOLDIsolated
• IsolineA line connecting points of equal value for a given variable on a map or chart. These lines are fundamental...
• IsomerOne of two or more chemical compounds that have the same molecular formula but a different arrangement of...
• IsonephA line on a weather map connecting points that have an equal degree of cloudiness or average cloud cover...
• IsonivalA line on a map connecting points that have the same depth of snow or the same duration of snow cover. These...
• IsophaneA line on a map connecting points at which a specific, recurring biological event, or phenophase, occurs on...
• IsoplethA line drawn on a weather map or chart connecting points at which a given variable has a specified constant...
• IsopluvialA line drawn on a map connecting points that receive the same amount of precipitation during a specific...
• IsopreneA volatile organic compound (C5H8) emitted in large quantities by many species of vegetation, particularly...
• IsopycnalA line or surface connecting points of equal or constant density within a fluid medium such as the atmosphere...
• Isopycnal mixingThe process of fluid parcels mixing along surfaces of constant density, where there is no net change in...
• Isopycnal surfaceA surface within a fluid where the density is constant throughout. These surfaces are often used to track the...
• IsopycnicDescribing a process or state where the density of a fluid parcel remains constant. In atmospheric science...
• Isopycnic lineA line on a two-dimensional plot or map connecting points of equal density within a fluid. These lines are...
• Isopycnic surfaceA surface within a fluid body, such as the ocean or atmosphere, where the density of the fluid is uniform...
• IsoshearA line on a weather map connecting points of equal wind shear. Wind shear represents the change in wind speed...
• Isostatic adjustmentThe process by which the Earth's lithosphere responds to changes in load, such as the growth or melting of...
• IsostereA line on a chart, or a surface in the atmosphere or ocean, connecting points of equal specific volume, the...
• IsostericDescribing a line on a thermodynamic diagram or a surface on a three-dimensional plot that connects points of...
• Isosteric surfaceA surface within a fluid where all points have the same specific volume. Since specific volume is the...
• IsotachA line on a weather map connecting points of equal wind speed. These lines are used to visualize patterns of...
• Isotach analysisThe process of constructing and interpreting a weather map that displays lines of equal wind speed, known as...
• Isotach chartA meteorological chart that displays lines of equal wind speed, called isotachs, at a specific atmospheric...
• IsothermA line on a weather map or chart connecting points that have the same temperature at a given time or for a...
• Isotherm ribbonA narrow band on a weather map where isotherms are closely packed, indicating a strong temperature gradient...
• IsothermalDescribing a process or a region in which temperature remains constant. An isothermal layer in the atmosphere...
• Isothermal atmosphereA theoretical atmospheric model where the temperature is assumed to be constant with height. While not...
• Isothermal equilibriumA state of thermodynamic equilibrium where the temperature is uniform throughout a system and remains...
• Isothermal processA thermodynamic process during which the temperature of a system remains constant. For an ideal gas...
• IsotimicDescribing a line on a map or chart that connects points of equal value for any given meteorological...
• Isotimic lineA line on a meteorological chart or diagram that connects points of equal value for a specific atmospheric...
• Isotimic surfaceA three-dimensional surface within the atmosphere where all points share the same value of a specific...
• IsotopeAtoms of the same element that have the same number of protons but different numbers of neutrons, resulting...
• Isotopic tracerAn isotope, either stable or radioactive, used to track the movement and transformation of substances within...
• IsotropicDescribing a medium or property that exhibits identical physical characteristics regardless of the direction...
• Isotropic radiationElectromagnetic radiation that has the same intensity in all directions from its source. In atmospheric...
• Isotropic radiatorA hypothetical point source that radiates energy uniformly in all directions. While not physically...
• Isotropic targetAn idealized object in radar meteorology that scatters incident electromagnetic radiation equally in all...
• Isotropic turbulenceA state of turbulence where the statistical properties of the turbulent eddies are independent of direction...
• Issuance timeThe time the product is transmitted.
• ITCZInter-tropical Convergence Zone. The region where the northeasterly and southeasterly tradewinds converge...
• ITWASIntegrated Terminal Weather System
• Ivory pointA fixed reference mark, typically made of ivory, used on mercury barometers to establish a precise zero point...

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