atmospheric boil (s) (noun)
, terrestrial scintillation, atmospheric shimmer, optical haze; atmospheric boils (pl)
A generic term for scintillation phenomena observed in light that reaches the eyes from sources lying within the earth's atmosphere.
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.
atmospheric boundary layer (s) (noun)
, surface boundary layer, surface layer, friction layer, ground layer; atmospheric boundary layers (pl)
1. 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.
2. The thin layer of air adjacent to the earth's surface, usually considered to be less than 300 feet (91 meters) high.
3. The thin layer of air adjacent to the earth's surface, extending 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.
atmospheric braking (s) (noun)
, atmospheric brakings (pl)
1. 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 slowing 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."
atmospheric chemistry (s) (noun)
, atmospheric chemistries (pl)
The study of the production, transport, modification, and removal of atmospheric components in the troposphere and stratosphere.
atmospheric composition (s) (noun)
, atmospheric compositions (pl)
The chemical constituents and abundance in the earth's atmosphere of its constituents, including nitrogen, oxygen, argon, carbon dioxide, water vapor, ozone, neon, helium, krypton, methane, hydrogen, and nitrous oxide.
atmospheric condensation (s) (noun)
, atmospheric condensations (pl)
The transformation of water in the air from a vapor phase to dew, fog, or a cloud.
atmospheric control (s) (noun)
, atmospheric controls (pl)
Any 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.
atmospheric convection current (s) (noun)
, atmospheric convection currents (pl)
The vertical movement of air currents resulting from temperature variations.
atmospheric cooler (s) (noun)
, natural-draft cooler; atmospheric coolers, natural-draft coolers (pl)
1. In mechanical engineering, a cooler for fluids that uses air circulation obtained by natural convection to cool certain hot, fluid-filled tubes.
2. A fluids cooler that utilizes the cooling effect of ambient air surrounding hot, fluids-filled tubes.
atmospheric corrosion (s) (noun)
, atmospheric corrosions (pl)
The gradual destruction or alteration of a metal or alloy by contact with substances present in the atmosphere; such as, oxygen, carbon dioxide, water vapor and sulfur, and chlorine compounds.
atmospheric density (s) (noun)
, atmospheric densities (pl)
The ratio of the mass of a portion of the atmosphere to the volume it occupies.
atmospheric diffusion (s) (noun)
, atmospheric diffusions (pl)
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.
atmospheric dispersion (s) (noun)
, atmospheric dispersions (pl)
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 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.
atmospheric distillation (s) (noun)
, atmospheric distillations (pl)
1. 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.
2. In chemical engineering, a distillation operation conducted at atmospheric pressure, in contrast to vacuum distillation or pressure distillation.
atmospheric disturbance (s) (noun)
, atmospheric disturbances (pl)
1. Any agitation or disruption of the atmospheric steady state.
2. Any interruption of a state of equilibrium of the atmosphere.
3. An area showing signs of a developing cyclonic circulation.
4. A periodic disturbance 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.
Related ball, sphere-word units: