1. Relating, referring to, or taking place in the area of skies surrounding the Earth: The illumination by the lights of the city created an atmospheric haze above the city.
2. Dependent on, caused by, or resulting from the collection of gases surrounding the surface of the Earth or other celestial bodies: The moon glimmered through the atmospheric mist caused by the wispy clouds in the sky.
3. Descriptive of a distinctive quality or effect in a location: The atmospheric music in the background of the restaurant encouraged patrons to relax and to enjoy their meals.

1. The soaking up of radiation by the air and moisture in the mixture of gases surrounding the Earth's surface: In Howard's physics class, two of the students invented a gauge to measure atmospheric absorption.
2. The reduction of the energy of microwaves by the presence of moisture in the gases surrounding the Earth: The static in the skies at night in the local area appeared to cause the atmospheric absorption of the microwaves, which were interfering with the radar system.

The propagation of sound through the layer of gases surrounding the Earth's surface affects sound in predictable ways depending on conditions, such as temperature and precipitation: When setting up for the outdoor concert, the sound engineers had to take atmospheric acoustics into consideration, including factors such as moisture in the air, placement of speakers on the ground, etc.

The depletion of electromagnetic energy in the layers of gases surrounding the surface of the Earth because of absorptions or diffusions: The astronomers discovered that the rate of the atmospheric attenuation of the electric sound waves had decreased when passing through dense clouds.

The generic term for scintillation phenomena observed in light that reaches the eyes from sources liying within the Earth's atmosphere: An atmospheric boil, or a scintillation, refers to the rapid fluctuations in the amplitude and phase of electromagnetic or acoustic waves that have propagated through a medium containing fluctuations in refractive index, such as the atmosphere.

The most common example of optical scintillation is the "twinkling" of stars observed through the atmosphere because it arises as a result of random angular scattering produced by refractive index fluctuations.

Fluctuations in the amplitude of different frequency components in the spectrum of an object can give rise to apparent changes in its color (chromatic scintillation). An example is the random red and blue twinkling of bright stars near the horizon.

Scintillation statistics have been used to study turbulence in regions ranging from the planetary boundary layer to the ionosphere, as well as interplanetary and interstellar space and it is important for astronomical imaging, optical and radio communications, laser and acoustical propagation, active and passive remote sensing, and the performance of the Global Positioning System.

The thin layer of air adjacent to the Earth's surface; surface layer: The atmospheric boundary layer is usually considered to be less than 300 feet (91 meters) high.

In the Earth's atmosphere, the planetary boundary layer is the air layer near the ground affected by diurnal heat, moisture, or momentum transfer to or from the surface.

The thin layer of air adjacent to the Earth's surface; ground layer: The atmospheric boundary layer extends up to the so-called anemometer level (the base of the Ekman layer [thin top layer of the sea]). Within this layer the wind distribution is determined largely by the vertical temperature gradient and the nature and contours of the underlying surface, and shearing stresses are approximately constant.

The process of slowing down an object entering the atmosphere of the Earth, or other planet from space, by using the drag exerted by air or other gas particles in the atmosphere and the action of the drag so exerted: Atmospheric brakings involve the deceleration of the speed of descent, such as that which is initiated or enhanced deliberately when landing a space vehicle as it encounters the drag of a planetary atmosphere.

The academic study of the production, transport, modification, and removal of atmospheric components in the troposphere and stratosphere: Jerry's mother is a scientist who does research in atmospheric chemistry involving the Earth's atmosphere in combination with environmental chemistry, physics, oceanography, and other disciplines.

The chemical constituents and abundance of its components in the Earth's atmosphere: The atmospheric composition include nitrogen, oxygen, argon, carbon dioxide, water vapor, ozone, neon, helium, krypton, methane, hydrogen, and nitrous oxide.

The transformation of water in the air from a vapor phase to dew, fog, or to a cloud: Early the next morning Stella could see the moisture on the blades of grass on the lawn due to atmospheric condensation.

A device or system designed to operate movable aerodynamic control surfaces to direct a guided missile in an atmosphere dense enough for such controls to be effective and the control provided by such devices: Judy read about atmospheric controls being able to conduct the direction of a projectile in an atmosphere thick enough for controlling instruments to be efficient.

The vertical movement of air currents resulting from temperature variations: Mr. Air explained the facts concerning atmospheric convection currents and that they arose from the changing differences in heat and cold in the atmosphere.

In mechanical engineering, a cooler for fluids that uses air circulation obtained by natural convection to cool down certain hot, fluid-filled tubes: An atmospheric cooler is a liquid cooler that utilizes the chilling effect of ambient air encompassing the tubes filled with hot fluids.

The gradual destruction or alteration of a metal or alloy by contact with substances present in the atmosphere: Atmospheric corrosion can occur by certain elements like oxygen, carbon dioxide, water vapor, sulfur, and chlorine compounds.

In meteorology, the ratio of the mass of a portion of the atmosphere to the volume it occupies: When the couple went out for a walk in the early morning, they could hardly see in front of them due to thick fog, or an atmospheric density.

The exchange of fluid parcels between regions in the atmosphere in the apparently random motions of a scale too small to be treated by the equations of motion: Mr. Fox explained the expression atmospheric diffusion by using an example of air pollutants in the air.

The spreading of a star image into a small spectrum as its light travels through the Earth's atmosphere: The atmosphere acts in the same way as a glass prism. The path the light takes, or the atmospheric dispersion, depends to a small extent on its wavelength. As a result, the blue light from a star seems to come from slightly closer to the zenith than the red light.

A refining process in which crude oil components are separated at atmospheric pressure by heating to temperatures of about 600-750°F and the subsequent condensing of the fractions by cooling: In chemical engineering, atmospheric distillation is an operation conducted at atmospheric pressure, in contrast to vacuum distillation or pressure distillation.

Any agitation, disruption, or interruption of the state of equilibrium of the atmosphere: An atmospheric disturbance can take place in an area showing signs of a developing cyclonic circulation.

An atmospheric disturbance can be a periodic disruption in the fields of atmospheric variables, like surface pressure or geopotential height, temperature, or wind velocity, which may either propagate (traveling wave) or not (stationary wave).

Atmospheric waves range in spatial and temporal scale from large-scale planetary waves (Rossby waves or giant meanders, twists and turns, in high-altitude winds that are a major influence on weather) to minute sound waves.

A major perturbation (disturbance and trouble) of the close artificial satellite orbits: An atmospheric drag is caused by the resistance of the atmosphere. The secular effects are decreasing eccentricity, semidiameter (apparent radius of a celestial body when viewed as a disk from the earth), and period.

An atmospheric drag can be a critical perturbation of the orbits of closely adjacent low-orbit artificial satellites due to atmospheric resistance. The effects, extending over ages of time, are semidiameter, period, and decreasing eccentricity.

In geophysics, a layer of the troposphere in which refractive properties are such as to trap a large proportion of certain high frequency radiations: An atmospheric duct is a stratum of the troposphere within which the refractive index varies so as to confine, within the limits of the stratum, the propagation of an abnormally large proportion of any radiation of sufficiently high frequency, as in a mirage.

Atmospheric ducting is a mode of propagation of electromagnetic radiation, usually in the lower layers of the Earth’s atmosphere, where the waves are bent by atmospheric refraction.

The atmosphere's electric field strength in volts per meter at any specified point in time and space near the Earth's surface and in fair-weather areas: A typical datum is about 100 and the field is directed vertically in such a way as to drive positive charges downward.

An atmospheric electric field is a quantitative term indicating the electric field strength of the atmosphere at any specified point in space and time.
An atmospheric electric field is also a measure, in volts per meter, of the electrical energy in a given portion of the Earth's atmosphere at a given time.

The scientific study of electrical processes occurring within the atmosphere: Atmospheric electricity occurs in the lower atmosphere, including both the intense local electrification accompanying storms and the much weaker fair-weather electrical activity over the entire globe produced by the electrified storms continuously in progress.

Atmospheric electricity is an electrical phenomena, regarded collectively, that occurs in the Earth's atmosphere.

These phenomena include not only such striking manifestations as lightning and St. Elmo's fire, but also less noticeable but more ubiquitous effects, such as atmospheric ionization, the air–earth currents, and other quiescent electrical processes.

The existence of separated electric charges in the atmosphere is a consequence of many minor processes, such as spray electrification, dust electrification, etc. and a few major processes including cosmic-ray ionization, radioactive-particle ionization, and thunderstorm electrification.

The maintenance of the prevailing atmospheric electric field is now widely believed to be due to thunderstorm effects.

An expression for early steam engine designs: The term atmospheric engine was given this name because the pressure of the steam was the same as, or near, the envelop of gasses surrounding the Earth.

When Irene was in England, she visited the transportation museum and was impressed with the large atmospheric steam engines on display.

The penetration of any planetary atmosphere by any object from outer space: An atmospheric entry specifically applies to the penetration of the Earth's atmosphere by a crewed, or uncrewed, capsule or spacecraft.

The atmospheric entry is the penetration of human-made or natural objects from a planetary atmosphere by an object approaching from space, especially of the Earth's atmosphere by a re-entering spacecraft.

The reduction in intensity of light from an astronomical object by absorption and scattering in the Earth's atmosphere: Atmospheric extinction increases when the object is closer to the horizon because of the greater thickness of atmosphere through which its light must travel.

One of the constituents of air that consists of a gaseous mixture: Atmospheric gases primarily include nitrogen, oxygen, argon, carbon dioxide, water vapor, ozone, neon, helium, krypton, methane, hydrogen, and nitrous oxide, plus small amounts of other gases.

The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night.

Any atmospheric flow used to refer to the general circulation of the Earth and regional movements of air around areas of high and low pressure: On average, the atmospheric general circulation corresponds to large-scale wind systems arranged in several east–west belts that encircle the Earth.

Any foreign material that mixes with and contaminates the air in the atmosphere: One well-known atmospheric impurity is smog, which is comprised of fog and chemical fumes and causes a yellowish atmosphere.

Electromagnetic radiation, caused by natural electrical disturbances in the atmosphere; atmospherics; sferics; strays: Atmospheric interferences interfere with radio systems.

The radio frequency electromagnetic radiation originated principally in the irregular surges of charge in thunderstorm lightning discharges.

Atmospherics are heard as a quasi-steady background of crackling noise (static) on certain radio frequencies, such as those used to broadcast AM radio signals.

Since any acceleration of electric charge leads to emission of electromagnetic radiation, and since the several processes involved in propagation of lightning lead to very large charge accelerations, the lightning channel acts like a huge transmitter, sending out radiation with frequencies of the order of 10 kHz.

An atmospheric condition in which the air temperature rises with increasing altitude, holding surface air down and preventing dispersion of pollutants: Atmospheric inversion is a departure from the usual increase or decrease of an atmospheric property with altitude.

Atmospheric inversion usually refers to an increase in temperature with increasing altitude, which is a departure from the usual decrease of temperature with height.

In other words, atmospheric inversion is a reversal in the normal temperature lapse rate, the temperature rising with increased elevation instead of falling.

Usually within the lower atmosphere (the troposphere), the air near the surface of the Earth is warmer than the air above it, largely because the atmosphere is heated from below as solar radiation warms the Earth's surface, which in turn then warms the layer of the atmosphere directly above it.

The process by which neutral atmospheric molecules or atoms are rendered electrically charged chiefly by collisions with high-energy particles: Atmospheric ionization is the charging of neutral particles in the atmosphere through violent contact with charged particles.

Atmospheric ionization is the production of ions in the atmosphere by the loss of an electron from a molecule, typically, for example, by cosmic rays or cosmic radiation.

Cosmic rays and radioactive decay are the main sources of atmospheric ionization.

Radioactivity at the surface can also produce ions in the lowest layer of the atmosphere.

The environmental rate of decrease with height for an atmospheric variable or temperature: The atmospheric lapse rate is the rate of decrease with height and not simply the rate of change.

While most often applied to the Earth's atmosphere, the concept can be extended to any gravitationally supported ball of gas.

In other words, the atmospheric lapse rate involves the decrease of temperature with elevation in the atmosphere.

The "environmental lapse rate" is determined by the distribution of temperature in the vertical at a given time and place and should be carefully distinguished from the process lapse rate, which applies to an individual air parcel.

Any one of a number of layers of the atmosphere, most commonly distinguished by temperature distribution: The atmospheric layer is also known as the "atmospheric shell" or "atmospheric region".

The atmospheric layer is one of several strata or layers of the Earth's atmosphere.

Temperature distribution is the most common criterion used for denoting the various shells.

Loud sounds heard during radio reception interferences in the air: Sally found out that atmospheric noise was caused by natural processes in the atmosphere, mainly by lightning discharges during thunderstorms!

A branch of meteorological physics or physical meteorology in which phenomena are seen occurring in the sky and are described and explained: Atmospheric optics is the study of the optical characteristics of the atmosphere or products of atmospheric processes.

The term atmospheric optics is usually confined to visible and near visible radiation, however, unlike meteorological optics, it routinely includes temporal and spatial resolutions beyond those discernible with the naked eye.

"Meteorological optics" is that part of atmospheric optics concerned with the study of patterns observable with the naked eye.

This restriction is often relaxed slightly to allow the use of simple aids, such as binoculars or a polarizing filter.

Topics included in meteorological optics are sky color, mirages, rainbows, halos, glories, coronas, and shines.

A branch of science dealing with the investigation and study of the physical phenomena of the atmosphere: Judy was very interested in geophysics and decided to take some courses in atmospheric physics to learn more about the observable occurrences or facts of the atmosphere.

A unit of barometric pressure that is taken to be the standard pressure of the Earth's atmosphere at sea level: The average atmospheric pressure at sea level is approximately 14.7 pounds per square inch.

With an increasing altitude, the atmospheric pressure decreases. For example, at 30,000 feet, approximately the height of Mt. Everest, the air pressure is 4.3 pounds per square inch.

The atmospheric pressure at any point in an atmosphere is due solely to the weight of the atmospheric gases above the point concerned.

In petroleum engineering, the preparation of petroleum specimens for testing purposes: Atmospheric pressure cure is achieved by aging petroleum samples at normal atmospheric pressure for a given length of time at a specific temperature and humidity.

In geophysics, the radiation emitted by the atmosphere either upward into space or downward toward the Earth: Atmospheric radiation consists mainly of long-wavelength terrestrial radiation plus the small amount of short-wavelength solar radiation absorbed in the atmosphere.

Atmospheric radiation can also be said to be infrared radiation which is released by or also produced by the atmosphere.

1. A program involving the detection or measurement of electromagnetic radiation: ARM is applied in particular to devices used to measure infrared radiation.
2. Research including the detection of microwave thermal radiation and similar weak wide-band signals that resemble noise and are obscured by receiver noise: The primary atmospheric radiation measurement application using an atmospheric radiometer has been on board spacecraft measuring atmospheric and terrestrial radiation, and they are mostly used for meteorological or oceanographic remote-sensing.

Their secondary application is also meteorological, as zenith-pointing surface instruments that view the Earth's atmosphere in a region above the stationary instrument.

By understanding the physical processes associated with energy emission at these wavelengths, scientists can calculate a variety of surface and atmospheric parameters from these measurements, including air temperature, sea surface temperature, salinity, soil moisture, sea ice, precipitation, the total amount of water vapor and the total amount of liquid water in the atmospheric column directly above or below the instrument.

A radio wave that is propagated by reflection through the atmosphere by reflections and refractions occurring in the atmosphere: Atmospheric radio waves may include either the ionospheric wave or the tropospheric wave, or both of them.

1. The light passing through the Earth's atmosphere: Atmospheric refraction includes both astronomical refraction and terrestrial refraction.
2. An apparent upward displacement of celestial objects relative to the horizon as light from them is bent toward the vertical by the decreasing density with altitude of the Earth's atmosphere: Atmospheric refraction is greatest for objects on the horizon and negligible at elevations higher than about 45 degrees.

The angular difference between the apparent zenith distance of a celestial body and its true zenith distance is produced by refraction effects as the light from the body penetrates the atmosphere.

Any refraction caused by the atmosphere's normal decrease in density with height.

Near surfaces on the Earth, those within a few meters or so, are usually dominated by temperature gradients.

A diffusion or alteration in the direction of the propagation, frequency, or polarization of electromagnetic radiation: Atmospheric scattering occurs through contact with, or by interaction with the atoms in the atmosphere.

The twinkling of stars (fluctuation of intensity) as seen through a planet's atmosphere: Atmospheric scintillation is caused by a star's light being distorted by the Earth's atmosphere and atmospheric scintillation is greater for bright stars that are low on the horizon.

The measurement of atmospheric conditions above the effective range of surface weather observations; atmospheric profiling: Atmospheric sounding is a calculation of the vertical spread of physical properties in the atmosphere including temperature, wind velocity, wind direction, pressure, ozone concentration, pollution, and water content in a fluid form.

A process for bringing freshly placed concrete, or cement products, to a required strength and quality by maintaining the humidity and temperature at specified levels for a given period of time: Atmospheric steam curing is usually done at a maximum ambient temperature between 100 and 200°F., or 40 and 95°C.

The constituting elements that characterize the atmosphere: An atmospheric structure includes wind direction and velocity, altitude, air density, and the velocity of sound.

Particles drifting in the air: Atmospheric suspensoids can be specks of dust that are finely divided and suspended in the atmosphere.

A movement of atmospheric masses caused by the gravitational attraction of the sun and moon and by daily solar heating; amplitudes are minute except in the upper atmosphere: An atmospheric tide is a tidal movement of the atmosphere resembling an ocean tide but caused principally by diurnal temperature changes.

Both the sun and moon produce atmospheric tides, and there also exist both gravitational tides (gravitational attraction of the sun or moon) and thermal tides (differential heating of the atmosphere by the sun).

The rhythmic, periodic oscillation of the Earth's atmosphere occurs because of the gravitational effects of the Earth, sun, and moon and to the absorption of radiation by the atmosphere.

Haziness in the atmosphere due to aerosols, such as dust: When atmospheric turbidity is zero, the sky has no dust, as measured by a sun photometer, an instrument that measures luminous intensity or brightness, luminous flux, light distribution, color, etc.

Random fluctuations of the atmosphere often causing major deformations of its fluid flow: Atmospheric turbulence involves the mixing of warm and cold air in the atmosphere by wind, which causes clear-air turbulence that is experienced during airplane flight, as well as poor astronomical vision or the blurring of images seen through the atmosphere.

A range of wavelengths in which the atmosphere is partly or largely transparent: An atmospheric window is a wavelength band in the electromagnetic spectrum that is able to pass through the Earth's atmosphere with relatively little attenuation through absorption, scattering, or reflection.

An atmospheric window takes place in the observable infrared and radio areas of the spectrum.