sphero-, spher-, -sphere-

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.