- المجال: 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 type of wind profiler specially designed to study the lower part of the troposphere. Because clear-air reflectivities in the boundary layer are usually orders of magnitude higher than in the upper troposphere, these profilers can be smaller, lower powered, and less expensive than those profilers designed to cover higher regions of the atmosphere (see, e.g.,, MST radars). Boundary layer radars are generally characterized by short pulse lengths (less than 100 m) and the ability to make measurements starting at 100–200 m above the radar and extending to at least 2–4 km under typical atmospheric conditions. To satisfy these requirements, boundary layer radars usually operate in the UHF radar band.
Industry:Weather
A type of turbulence closure where the shape of the vertical profile of a variable is assumed to be known or idealized a priori, leaving only the parameters of that profile shape to be modeled or forecast. For example, in the convective mixed layer, the potential temperature profile is idealized as uniform with height, requiring only a single value of mixed-layer potential temperature to specify the potential temperature at every height within that layer. A different example is the potential temperature in the stable boundary layer, which when idealized as an exponential shape requires only two variables (temperature decrease at the surface and e-folding depth) to specify the potential temperature at all heights within that layer. This type of turbulence closure is less than first-order statistical closure and is sometimes called half-order closure.
Industry:Weather
A unit of signaling speed that is the number of signal events per second. Depending on the number of bits per signal event, the baud rate can be different from the bit rate. In modern systems, a signal event represents more than one bit, so the baud rate is less than the bit rate (or bits per second).
Industry:Weather
A unit of pressure equal to 106 dyne cm−2 (106 barye), 1000 millibars, 29. 53 inches of mercury.
Industry:Weather
A type of radar antenna that forms a beam having a greater beam width in azimuth than in elevation, or vice versa. In physical dimensions, its long axis lies in the plane of smaller beam width. A beam that is wide in azimuth angle and narrow in elevation angle is employed on height-finding radars. Search radars usually have beams narrow in azimuth but broad in elevation angle. In general, the narrower the beam, the greater the angular resolution.
Industry:Weather
A thermometer with a sensitive element made to approximate a blackbody by covering it with lamp black. The thermometer is placed in an evacuated transparent chamber that is maintained at constant temperature. The instrument responds to irradiance, modified by the transmission characteristics of its container.
Industry:Weather
A transparent glass slide, marked with calibration lines of temperature and depth, that, when superimposed against a bathythermograph slide, makes it possible to read observed values of temperature and depth.
Industry:Weather
A thermometer in which the sensitive element consists of a compound strip of metal formed by welding together two strips of metal having different coefficients of expansion. The curvature of the strip is a function of its temperature. It is a type of deformation thermometer.
Industry:Weather
A thermoelectric thermometer used for measuring air temperature. The name is derived from the fact that the reference thermocouple is placed in an insulated bottle.
Industry:Weather
