- 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 radar that transmits a waveform that is continuously and regularly modulated in frequency, typically using a linear sweep or sawtooth wave for the frequency modulation. In such a radar the range to a target is determined by the frequency of the signal it returns. Extremely high range resolution can be achieved by measuring the returned signal in narrow frequency bands.
Industry:Weather
A system for the precise control of the approach and landing of aircraft by an operator on the ground. Precision approach radar is employed to view the aircraft, and the radar operator “talks” the pilot down by giving him his position and suggested corrections for maintaining the “perfect approach. ” Currently, GCA is a required facility at an all-weather airport. If perfectly operated, this system would ensure safe landing under zero ceiling and visibility conditions; however, to provide a safety factor, GCA minimums are prescribed at nearly all installations.
Industry:Weather
(Chinese for “wind and cloud. ”) A geostationary meteorological satellite launched by China and stationed over the Indian Ocean at 105°E longitude. After a successful launch on 10 June 1997 the satellite began regular operations late in 1997. Multi-spectral imagery is provided by a modified version of the VISSR instrument, very similar to those used on the GMS satellites. In early 1998 the satellite encountered difficulties with its data link. A separate series of Chinese polar orbiting satellites have also used the Fengyun name (Fengyun 1A and 1B).
Industry:Weather
Relates tornado intensity indirectly to structural and/or vegetative damage. The estimated wind speed is calculated using the following formula: V = 6. 30 (F+2)1. 5 m s−1. A six-point scale has been developed that corresponds to the following wind-speed estimates:
F0 (light damage): 18–32 m s−1
F1 (moderate damage): 33–49 m s−1
F2 (considerable damage): 50–69 m s−1
F3 (severe damage): 70–92 m s−1
F4 (devastating damage): 93–116 m s−1
F5 (incredible damage):117–142 m s−1. Although extremely dependent on the design of a structure and the tree type, the following visual characteristics of the damage have been assigned to the F-scale. F0 - Some damage to chimneys; branches broken; shallow-rooted trees knocked over. F1 - Surface of roofs peeled off; mobile homes pushed off foundations or overturned; moving autos pushed off road. F2 - Roofs torn off frame houses; mobile homes demolished; boxcars pushed over; large trees snapped or uprooted. F3 - Roofs and some walls torn off well-constructed houses; trains overturned; most trees in forest uprooted; heavy cars lifted off ground and thrown. F4 - Well-constructed houses leveled; structures with weak foundations blown off; large missiles generated. F5 - Strong frame houses lifted off foundations and carried considerable distances; automobile- sized missiles flying through the air for distances in excess of 100 m; trees debarked.
Industry:Weather
Ordinarily, the ratio of two independent estimates of a common variance. It is used as a significance test in analysis of variance and is known in this regard as the F- test.
Industry:Weather
A stationary time series in which the joint probability distribution of any sequence of values, x(t1), x(t2),. . . , x(tn), is a multivariate normal distribution, or a stationary random process that is completely determined by its spectrum or autocorrelation function.
Industry:Weather
A function that is the known solution of a homogenous differential equation in a specified region and that may be generalized (if the equation is linear) to satisfy given boundary or initial conditions, or a nonhomogeneous differential equation. It is thus an alternative method to the Fourier transform or Laplace transform, applicable to many of the same problems. The Green's function method takes a fundamental solution and assigns it a weight at each point, say, of the boundary, according to the value of the given boundary condition there; the Fourier method analyzes the entire boundary condition into wave components thus assigning each of these a weight or amplitude. Both methods then obtain the final solution by summation or integration.
Industry:Weather
A series of satellites operated by the Japanese Meteorological Agency. The GMS program was initiated with the launch of GMS-1 in July 1977. Multi-spectral imagery is provided by a slightly modified version of the VISSR instrument used on GOES satellites. The GMS is positioned at 140°E longitude.
Industry:Weather
A U. S. Navy oceanographic satellite that used a radar altimeter to obtain closely spaced, precise mapping of the earth's geoid over the ocean. GEOSAT was launched on 12 March 1985 and produced maps of seafloor topography with unprecedented resolution.
Industry:Weather
The globally integrated communications that provides for the collection and distribution of meteorological data within the World Weather Watch.
Industry:Weather
