- المجال: Weather
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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 means of representing wind speed in the plotting of a synoptic chart; it is a short straight line drawn obliquely toward lower pressure from the end of a wind-direction shaft. In the commonly used five-and-ten system, one barb represents 10 knots and a half-barb represents 5 knots. Previously, a full barb was used to represent a Beaufort force of 2, with a half- barb to represent a Beaufort force of 1. Customarily, the barb is often drawn obliquely or perpendicular to the wind direction. See pennant.
Industry:Weather
A means of representing wind speed in the plotting of a synoptic chart; it is a short straight line drawn obliquely toward lower pressure from the end of a wind-direction shaft. In the commonly used five-and-ten system, one barb represents 10 knots and a half-barb represents 5 knots. Previously, a full barb was used to represent a Beaufort force of 2, with a half- barb to represent a Beaufort force of 1. Customarily, the barb is often drawn obliquely or perpendicular to the wind direction. See pennant.
Industry:Weather
A rare and randomly occurring bright ball of light observed floating or moving through the atmosphere close to the ground. Observations have widely varying identifying characteristics for ball lightning, but the most common description is that of a sphere having a radius of 15–50 cm, orange or reddish in color, and lasting for only a few seconds before disappearing, sometimes with a loud noise. Most often ball lightning is seen in the vicinity of thunderstorms or a recent lightning strike, which may suggest that ball lightning is electrical in composition or origin. Considered controversial due to the lack of unambiguous physical evidence for its existence, ball lightning is becoming more accepted due to recent laboratory recreations resembling ball lightning. Despite the observations and models of these fire balls, the exact mechanism(s) for naturally occurring ball lightning is unknown.
Industry:Weather
1. Same as karaburan. 2. Generally, any storm (especially a thunderstorm) accompanied by dense, dark clouds.
Industry:Weather
1. Same as hydraulic jump. 2. A tidal wave that propagates as a solitary wave with a steep leading edge up certain rivers. Bore formation is favored in wedge-shaped shoaling estuaries at times of spring tides. Other local names include eagre (River Trent, England), pororoca (Amazon, Brazil), and mascaret (Seine, France).
Industry:Weather
1. Pertaining to a barometer or to the results obtained by using a barometer. 2. Often used in the same sense as pressure (atmospheric), for example, “barometric gradient” for pressure gradient.
Industry:Weather
1. In general, a range of frequencies specified by the number of hertz contained within the band or by the upper and lower limiting frequencies. 2. The range of frequencies that a device is capable of generating, handling, or accommodating; usually the range in which the response is within 3 dB of the maximum response. For example, the bandwidth of a modulated signal or of a bandpass filter is commonly defined by the frequencies at which the power spectral density is 3 dB (or a factor of 2) less than that within the band. 3. The amount of frequency space occupied by a signal and required for effective transfer of information by the signal. In data transmission, the greater the bandwidth, the greater the capacity to transmit data bits.
Industry:Weather
1. In general, a light wind. In the Beaufort wind scale, this is a wind between 4 and 10 kt (4 and 12 mph). 2. In the Beaufort wind scale (Beaufort wind force numbers 2–6), a wind speed ranging from 4 to 27 kt (4 to 31 mph) and categorized as follows: light breeze, 4–6 kt; gentle breeze, 7–10 kt; moderate breeze, 11–16 kt; fresh breeze, 17–21 kt; and strong breeze, 22–27 kt.
Industry:Weather
1. Heat flux averaged over a layer of air, such as the boundary layer. 2. Heat-flux divergence or difference between the top and bottom of a layer.
Industry:Weather
1. For plane-wave radiation incident on a scattering object or a scattering medium, the ratio of the intensity scattered in the direction toward the source to the incident irradiance. So defined, the backscattering cross section has units of area per unit solid angle, for example, square meters per steradian. 2. In common usage, synonymous with radar cross section, although this can be confusing because the radar cross section is 4π times the backscattering cross section as defined in 1) and has units of area, for example, square meters. See differential backscattering cross section; compare radar cross section.
Industry:Weather
