- 行业: Weather
- Number of terms: 60695
- Number of blossaries: 0
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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, ...
Hard squalls from the northeast in Libya and Africa. They are sudden and frequent and are accompanied by heavy rain and thunder.
Industry:Weather
Heavily rimed snow particles, often called snow pellets; often indistinguishable from very small soft hail except for the size convention that hail must have a diameter greater than 5 mm. Sometimes distinguished by shape into conical, hexagonal, and lump (irregular) graupel.
Industry:Weather
Graphic representation of the meteorological conditions observed simultaneously in a vertical section of the atmosphere taken along the predicted horizontal path of the aircraft. Compare route cross section.
Industry:Weather
Ground ice found in regions of permafrost, or in other regions where present-day temperatures are not low enough to have formed it; ice that was formed in the geologic past.
Industry:Weather
Generic term for any gaseous electrical discharge that produces luminosity. Thus corona discharge is an example of glow discharge, but point discharge is not. Relatively high electric field strengths are required for glow discharges, for the density of radiatively recombining gas atoms and molecules must be high. While spark discharge and lightning fall under this definition, this term is most commonly applied to the more continuous, quiescent, and less brilliant discharges.
Industry:Weather
Generally, the period of the year during which the temperature of cultivated vegetation (i.e., the temperature of the vegetal microclimate) remains sufficiently high to allow plant growth. This is an important concept in agricultural climatology, but it suffers greatly from vagueness and complexity. The growing season is highly variable due to plant varieties as related to temperature sensitivity. Currently, the most common measure of this period, “the average length of growing season,” is defined as the number of days between the average dates of the last killing frost (see frost) in spring and the first killing frost of autumn. The lack of a positive, practical definition for (and means of determining) a “killing” frost seriously limits the scientific usefulness of this measure. To provide some economic significance, the effective growing season is defined as the length of growing season that prevails in 80% of the years. Another measure, the frost-free season, is defined as the interval between the last and first occurrences of 32°F temperatures in spring and fall. This may be observed exactly, but its relationship to the local microclimate is variable and nonspecific, and it does not consider differences in types of vegetation. Still a fourth measure, the vegetative period or vegetation season, attempts to allow for the greater microclimatic temperature range and for the general growth retardation by cold temperatures, and is defined as the summer period confined between occurrences of 42°F (or 41°F or 43°F) temperatures. At best, any of the above is an index of growing season length, rather than a direct measure of it. Basically, the growing season (and “killing frost”) should be defined biologically rather than meteorologically and should consider the detailed microclimate, plant resistance to frost, growth rate versus temperature, and probably other factors.
Industry:Weather
Generally, a fairly well-defined mass of fog observed in the distance, most commonly at sea. This is not applied to patches of shallow fog.
Industry:Weather
Generally, same as tailwind; specifically, a wind blowing abaft of the beam of a vessel; the opposite of opposing wind.
Industry:Weather
From the point of view of the submariner, an ice canopy containing many large skylights or other features that permit a submarine to surface. There must be more than 10 such features per 56 km (30 nautical miles) along the submarine's track.
Industry:Weather
For n positive numbers, the positive nth root of their product; that is, for the set of positive numbers x1, x2,. . . , xn, the geometric mean is the quantity (x1x2 xn)1/n. Compare arithmetic mean.
Industry:Weather
