sphero-, spher-, -sphere-

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!