- 行业: Weather
- Number of terms: 60695
- Number of blossaries: 0
- Company Profile:
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 period, in mid- or late autumn, of abnormally warm weather, generally clear skies, sunny but hazy days, and cool nights. In New England, at least one killing frost and preferably a substantial period of normally cool weather must precede this warm spell in order for it to be considered a true “Indian summer. ” It does not occur every year, and in some years there may be two or three Indian summers. The term is most often heard in the northeastern United States, but its usage extends throughout English- speaking countries. It dates back at least to 1778, but its origin is not certain; the most probable suggestions relate it to the way that the American Indians availed themselves of this extra opportunity to increase their winter stores. The comparable period in Europe is termed the Old Wives' summer, and, poetically, may be referred to as halcyon days. In England, dependent upon dates of occurrence, such a period may be called St. Martin's summer, St. Luke's summer, and formerly All-hallown summer.
Industry:Weather
A particle that acts as center for water condensation at relative humidity below, at, and above saturation (100%).
Industry:Weather
A pendant, curve-shaped region of reflectivity caused when precipitation is drawn into the cyclonic spiral of a mesocyclone. The hook echo is a fairly shallow feature, typically extending only up to 3–4 km in height before becoming part of a bounded weak echo region (BWER).
Industry:Weather
A pair of ions of equal and opposite charge formed by photoionization or by interaction of matter with any sufficiently energetic particles such as beta particles or alpha particles.
Industry:Weather
A numerical model constructed assuming a boundary condition along the equator. In many applications, the boundary condition is based upon vanishing meridional velocity along the equator. In some spectral formulations, the boundary condition may be formulated using symmetric or antisymmetric expansion (basis) functions. Compare atmospheric circulation model, circulation model, general circulation model.
Industry:Weather
A numerical index, often expressed as a percentage, corresponding to the ratio of the runoff from a basin in a given year to the annual average. Could be restricted to a particular season of interest.
Industry:Weather
A nonconducting material designed to reduce the transfer of energy or electric current between two materials.
Industry:Weather
A name applied to a wet sea fog or very fine drizzle that drifts in from the sea in coastal districts of eastern Scotland and northeastern England. It occurs most frequently in summer.
Industry:Weather
A mound of broken ice projecting upward, formed by ice deformation. The submerged counterpart of a hummock is termed a bummock. See also ridge.
Industry:Weather
