- 行业: 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 halo in the form of arcs in the vicinity of the halo of 46°, the form of which changes markedly with solar elevation. Sometimes given the names supralateral and infralateral, depending on whether the arcs are mainly above or below the sun. The supralateral arc appears to the sides and above the halo of 46° when the sun is low; it is concave toward the sun but vanishes for solar elevations above 32°. The infralateral arc can be either convex or concave. For some elevations, either arc may or may not be tangent to the halo of 46°. These arcs are explained by refraction through the 90° prism ends of columnar ice crystals oriented with their long axis horizontal.
Industry:Weather
A grid formed by a collection of geodesics, or, on the spherical earth, arcs of great circles. A typical example is the icosahedral, or icosahedral-hexagonal, grid, consisting of twenty equilateral triangular faces expanded onto a sphere, and further subdivided into smaller triangles. Other possibilities exist, such as grids obtained by the expansion of a cube with each of its sides subdivided into smaller elements by arcs of great circles.
Industry:Weather
A geological feature (e.g., a fault) or rock unit of low permeability that impedes the horizontal movement of groundwater flow, thereby causing high horizontal hydraulic gradients evident in the water table or other potentiometric surface.
Industry:Weather
A glassy, rootlike tube formed when a lightning stroke terminates in dry sandy soil. The intense heating of the current passing down into the soil along an irregular path fuses the sands. Concurrently, vaporization of soil moisture and possibly even vaporization of the sandy materials causes the molten material to be expanded into a tube with a diameter that may be over 2. 5 cm (1 in), but with a very thin wall. Fulgurites have been recovered in lengths of over 1. 5 m (5 ft).
Industry:Weather
A great circle on the earth's surface that is everywhere equidistant from the geomagnetic poles, that is, the equator in the system of geomagnetic coordinates. See aclinic line.
Industry:Weather
A general name (translated as "wind and cloud," frequently abbreviated FY) for several series of meteorological satellites maintained by the People�s Republic of China. The FY-1 series of sun-synchronous, polar-orbiting satellites was initiated with the launch of experimental satellites in 1988 and 1990. The first operational satellite in this series (FY-1C) was launched in May 1999. The FY-1C and FY-1D satellites have a 10-channel imaging instrument with four visible channels, three in the near-infrared, one in the short infrared, and two in the thermal infrared. A separate series of geostationary meteorological satellites, designated FY-2, are positioned at 105�E longitude. The first satellite in this series was launched in June 1997. The most recent Satellite FY-2D, with capabilities similar to the Japanese GMS-5, was launched in 2007.
Industry:Weather
A generally zonal acceleration produced by upward propagating gravity waves at levels where the waves break. Gravity waves grow in amplitude as they propagate upward from their surface source regions into lower-density regions. When large amplitudes are attained, the waves break, leading to turbulence and dissipation. This produces a zonal force per unit mass on the zonal mean flow. Gravity wave drag plays an important role in explaining the zonal mean flow and thermal structure at higher atmospheric levels, particularly in the mesosphere.
Industry:Weather
A geographical position determined by visual reference to the surface, by reference to one or more radio NAVAIDs, by celestial plotting, or by another navigational device.
Industry:Weather
A general methodology for constructing a smooth monotonic flux-form transport scheme. The flux computed by a monotonic, but diffusive, low-order scheme is combined (nonlinearly) with the flux computed by an accurate, but dispersive, high-order scheme to obtain the net transport flux. The high-order scheme is locally given the greatest possible weight without introducing oscillations (ripples) to the solution.
Industry:Weather
