- 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, ...
Irregularly spaced bandlike cirrus clouds that form nearly perpendicular to a jet stream axis. They are usually visible in the strongest portions of the subtropical jet and can also be seen in tropical cyclone outflow regions.
Industry:Weather
Instrument used to sample particles of a given size range according to their inertia. In the counterflow virtual impactor, a stream of air coming out of the instrument is used to reject particles with less than a specified inertia (size).
Industry:Weather
Instruments using absorption of electromagnetic radiation to sense humidity. Ultraviolet (UV) hygrometers use a single wavelength absorbed by molecular water vapor, such as the Lyman-alpha line produced by a hydrogen discharge tube. Infrared (IR) hygrometers can also operate on a single absorption line if the source is an infrared-emitting tunable diode laser (TDL), though broad-band instruments, which integrate the absorption across many individual lines, are also used. These instruments utilize Beer's law to estimate the density of absorption across the path between the source and a detector (e.g., an ionization tube for ultraviolet, or a photodiode for infrared), which contains the air sample. In many cases, these hygrometers have sufficient speed of response that they can resolve rapid turbulent fluctuations of humidity.
Industry:Weather
In W. Köppen's 1936 climatic classification, any type of climate that supports the growth of trees. This includes the tropical rainy climates, temperate rainy climates, and snow- forest climates. Excluded are the dry climates and polar climates. Tree climates are separated from polar climates by the isotherm representing the warmest month mean temperature of 10°C (50°F). They are separated from the dry climates by a certain value of annual precipitation as a function of temperature. In this latter sense they are also known as rainy climates. See Köppen–Supan line, arctic tree line.
Industry:Weather
In U. S. Weather observing procedures, a condition when the prevailing visibility is less than three statute miles and is rapidly increasing or decreasing by one-half mile or more during the period of observation. Variable visibilities are reported in the remarks section of the observations.
Industry:Weather
In U. S. Weather observing practice, that portion of sky cover through which higher clouds, blue sky, etc. , may be observed; opposed to opaque sky cover. Compare thin.
Industry:Weather
In tropical cyclones, Rossby waves that propagate azimuthally on the radial gradient of relative potential vorticity in the cyclone circulation.
Industry:Weather
In the United States, strong, easterly winds, often locally referred to as canyon winds, blowing out of the mouths of the canyons of the Wasatch Mountains onto the plains of Utah. They are produced by a strong large-scale west to east pressure gradient and are best developed when there is a large high over Wyoming or a vigorous low to the west or southwest in Utah or Arizona. In extreme cases they can exceed hurricane force. The strong winds are mainly limited to the canyons, especially in winter, but in some circumstances extend beyond them onto the plain.
Industry:Weather
