- 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, ...
The direction, with respect to true north, from which the wind is blowing; distinguished from magnetic wind direction. In all standard upper-air and surface weather observations, it is the true wind direction that is reported, usually in terms of tens of degrees in the 360° compass.
Industry:Weather
The discharge at a point, expressed as a function of time, due to a unit of effective rainfall that is applied uniformly over the contributing area during a specified period of time. The volume of the unit hydrograph is, by definition, one unit. The unit hydrograph is the response function of a river basin approximated as a linear system.
Industry:Weather
The distance that results by integrating the wind speed, measured at a point, over 24 hours.
Industry:Weather
The distribution of wave energy (for ocean surface waves) with frequency (1/ period) and direction. The 2D spectrum can be expressed either as a function of frequency and direction or as a function of the 2D wave vector. Integrated over direction, the 1D spectrum can be expressed as a function of frequency or of wavenumber. For gravity waves the square of the wave height is proportional to the potential energy of the sea surface and the energy spectrum is equivalent to the spectrum of sea surface fluctuations. See spectrum.
Industry:Weather
The drag force per unit area caused by wind shear. For example, the wind stress on the sea surface applies a friction force that can drive ocean currents. See Reynolds stresses, momentum flux, friction velocity.
Industry:Weather
The eastern boundary current of the subtropical gyre in the Indian Ocean. It covers the eastern half of the southern Indian Ocean in a broad northward movement but does not reach to the Australian coast, where the Leeuwin Current flows southward instead.
Industry:Weather
The eastward flux of mass, momentum, heat, moisture or any other property of a fluid by mean motion or by correlation with the eastward component of motion, that is, eddy flux.
Industry:Weather
The effect of (primarily) aerosols, through their total optical depth, in reducing the transmission of direct solar radiation to the surface below that through a purely molecular atmosphere. Measures of turbidity refer to the total aerosol optical depth, either directly at a specified wavelength (e.g., the Volz turbidity factor or the Ängström turbidity coefficient, which is referenced to a wavelength of 1 μm), or indirectly by the ratio of aerosol to Rayleigh optical depth (e.g., the Linke turbidity factor).
Industry:Weather
The effect of an orographic barrier in producing orographic precipitation to the windward of the base of the barrier as a result of orographic lifting mechanisms that produce rising motion upwind of the barrier. Orographic blocking of moist, stable approach flow is an example of one such mechanism.
Industry:Weather
The effective number of moles of ions in solution per molecule of salt. For dilute aqueous solutions, it is the number of ions in a molecule; it influences colligative properties such as solution freezing point depression in mixed cloud nuclei.
Industry:Weather
