- 行业: Weather
- Number of terms: 60695
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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, ...
1. The mountain wind of a canyon, that is, the nighttime down-canyon flow of air caused by cooling at the canyon walls. Because of the steepness of the slopes, canyon winds can be very strong. 2. (Or gorge wind. ) Any wind modified by being forced to flow through a canyon or gorge, especially by a strong pressure gradient as is the case with mountain-gap winds. The easterly Wasatch winds of Utah are examples. The speed of canyon winds may be increased as a jet-effect wind (see also gap wind), and their direction is rigidly controlled by the topography. 3. Same as Wasatch winds.
Industry:Weather
1. The motion of the index of an aneroid barometer after it has been subjected to a large and rapid change in pressure. This movement is a slow adjustment of the index toward the correct pressure. The physical cause of creeping is not clearly understood. 2. See soil creep.
Industry:Weather
1. The minimum channel slope that will produce critical flow. 2. In a saturated soil, the maximum hydraulic gradient above which piping or fluidization of the soil will occur.
Industry:Weather
1. The magnitude of a climatic response to a perturbing influence. 2. In mathematical modeling of the climate, the difference between simulations when the magnitude of a given parameter is changed. 3. In the context of global climate change, the equilibrium change in global mean surface temperature following a unit change in radiative forcing.
Industry:Weather
1. The fraction of all water drops in the path of a falling larger drop that make contact with the larger drop. Calculations using approximate drag forces between large and small cloud drops predict low collision efficiencies (<10%) when the large drop is less than 40 μm in diameter but collision efficiencies approaching 100% when the larger drop is greater than 80-μm diameter. Thus theory indicates that the collision–coalescence process for precipitation formation requires at least a small fraction of cloud drops to be larger than about 40-μm diameter. Because collision between drops does not necessarily result in coalescence, it is important to distinguish between collision efficiency and coalescence efficiency. Their product, termed the collection efficiency, gives the fraction of drops that collide and coalesce. See warm rain process. 2. The fraction of drops or aerosol particles colliding with precipitation particles. See accretion, washout.
Industry:Weather
1. The contraction of a vector field; also, a precise measure thereof. Mathematically, convergence is negative divergence, and the latter term is used for both. (For mathematical treatment, see divergence). Compare confluence. 2. The property of a sequence or series of numbers or functions that ensures that it will approach a definite finite limit.
Industry:Weather
1. Same as drainage area. This usage is common in British Commonwealth countries. 2. An area built specifically to collect rainfall.
Industry:Weather
1. See cascade shower. 2. (Obsolete. ) The spray vortex at the base of a waterspout.
Industry:Weather
1. The absence of apparent motion of the air. In the Beaufort wind scale, this condition is reported when smoke is observed to rise vertically, or the surface of the sea is smooth and mirrorlike. The National Weather Service reports a wind as calm when it is determined to have a speed of less than three knots. 2. See calm belt.
Industry:Weather
