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The American Meteorological Society promotes the development and dissemination of information and education on the atmospheric and related oceanic and hydrologic sciences and the advancement of their professional applications. Founded in 1919, AMS has a membership of more than 14,000 professionals, ...
A water mass identified by a salinity minimum found at a depth of about 800 m in the North Atlantic Ocean. It is formed in two varieties in the Labrador Sea and in the Iceland Sea, from where it spreads southward but is quickly absorbed by North Atlantic Deep Water. The equivalent water mass in the Pacific Ocean is known as Subarctic Intermediate Water.
Industry:Weather
A weak high that appears on mean charts of sea level pressure over the Arctic basin during late spring, summer, and early autumn.
Industry:Weather
A condition of reduced horizontal and slant visibility (but unimpeded vertical visibility) encountered by aircraft in flight over arctic regions.
Industry:Weather
The semipermanent, semicontinuous front between the deep, cold arctic air and the shallower, basically less cold polar air of northern latitudes; generally comparable to the antarctic front of the Southern Hemisphere.
Industry:Weather
“Any area in the high latitudes dominated by bare rocks, ice, or snow, and having a sparse vegetation and a low annual precipitation. ”
Thus stated, this includes portions of both ice cap and tundra regions of both hemispheres. The term barrens is sometimes used, but this has more general application.
Industry:Weather
The line of latitude 66°34′N (often taken as 66 °N). Along this line the sun does not set on the day of the summer solstice, about June 21, and does not rise on the day of the winter solstice, about December 22. From this line the number of twenty- four-hour periods of continuous day or of continuous night increases northward to about six months each at the North Pole.
Industry:Weather
The water mass formed in the Arctic Ocean by a combination of freezing on the arctic shelf and deep winter convection in the Greenland and Norwegian Seas. Freezing increases the salinity under the ice; the dense water sinks to the ocean floor and leaves the arctic basins to enter the Greenland and Norwegian Seas, where it mixes with water that sinks under the influence of surface cooling. The resulting water mass has a salinity of 34. 95 psu and a temperature of −0. 8° to −0. 9°C. It fills the Arctic Ocean at all depths below 800 m, the sill depth to the Atlantic. It enters the Atlantic in bursts, when the passage of atmospheric depressions lifts the thermocline and allows Arctic Bottom Water to flow over the sill. Overflow events in the Denmark Strait and across the Iceland–Faeroe sill contribute some 5 Sv (5 × 106 m3s−1) to the formation of North Atlantic Deep Water.
Industry:Weather
A type of air mass with characteristics developed mostly in winter over arctic surfaces of ice and snow. Arctic air is cold aloft and extends to great heights, but the surface temperatures are often higher than those of polar air. For two or three months in summer arctic air masses are shallow and rapidly lose their characteristics as they move southward. See also antarctic air, airmass classification.
Industry:Weather
A halo in the form of arcs that pass both obliquely and vertically through the 22° parhelia. The arcs of Lowitz are explained by refraction through the 60° prism of hexagonal plate ice crystals, oscillating as they descend. The principal axis of the plate must oscillate about the vertical by less than 30° to produce the pattern customarily called Lowitz arcs; larger oscillations lead to more complex arcs spreading far above and below the 22° parhelia and halo. See parhelion.
Industry:Weather
