- air mass
- a unit used in astronomy in measuring the absorption of light from the stars by the atmosphere. One air mass is the amount of absorption of light from a star directly overhead (at the zenith). The absorption of light from other stars is greater, because their light must pass obliquely through the atmosphere. If Z is the zenithal angle, the angle between the star and the zenith, then the absorption of its light is estimated to be sec Z air masses, "sec" being the secant trigonometric function.
Dictionary of units of measurement. 2015.
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air mass — air′ mass n. mer a body of air covering a wide area, exhibiting approximately uniform properties through any horizontal section • Etymology: 1890–95 … From formal English to slang
air mass — n. Meteorol. a huge, uniform body of air having the properties of its place of origin: see POLAR CONTINENTAL, POLAR MARITIME, TROPICAL CONTINENTAL, TROPICAL MARITIME … English World dictionary
Air mass — For other uses, see Air mass (astronomy) and Air mass (solar energy). Different air masses which affect North America, as well as othe … Wikipedia
air mass — a body of air covering a relatively wide area, exhibiting approximately uniform properties through any horizontal section. [1890 95] * * * In meteorology, a large body of air having nearly uniform conditions of temperature and humidity at any… … Universalium
air mass — noun a large body of air with uniform characteristics horizontally • Hypernyms: ↑atmosphere, ↑atmospheric state • Hyponyms: ↑high, ↑low, ↑depression * * * noun : a body of air extending hundreds or thousands of miles horizontally and someti … Useful english dictionary
air mass — /ˈɛə mæs / (say air mas) noun a large body of air, up to thousands of kilometres in extent, of uniform temperature and humidity, and impacting on an adjacent air mass at a well defined front; classified according to temperature as Arctic,… … Australian English dictionary
air mass — noun a) a widespread body of air, the properties of which can be identified as: b) having been established while that air was situated over a particular region of the earths surface (airmass source region) and … Wiktionary
air mass — noun Date: 1882 a body of air extending hundreds or thousands of miles horizontally and sometimes as high as the stratosphere and maintaining as it travels nearly uniform conditions of temperature and humidity at any given level … New Collegiate Dictionary
air mass — large body of air with shared temperature and humidity characteristics associated with its area of origin e.g. maritime or continental; tropical or polar … Geography glossary
air mass — n. section of air that maintains a consistent temperature and pressure … English contemporary dictionary