- 行业: Weather
- Number of terms: 60695
- Number of blossaries: 0
- Company Profile:
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 analysis of the annual growth rings of trees, leading to the calculation of significant indices of climate and general chronology of the past. The width of a tree ring was determined by the temperature and/or the moisture that prevailed during the year of its formation. Since stress from temperature and/or moisture variations reduces the width of the seasonal growth of a tree ring, dendrochronology has important application in the study of long-term climatic variations.
Industry:Weather
A crystal, particularly a planar ice crystal, with its macroscopic form (crystal habit) characterized by intricate branching structures of a treelike nature. Dendritic ice crystals possess hexagonal symmetry, and tend to develop when a crystal grows by vapor deposition at temperatures within a few degrees of −15°C, providing saturation is close to supercooled water. Similar forms occur by ice growth into supercooled liquid water at temperatures down to −10°C. Spatial dendrites grow in three dimensions from a central frozen drop.
Industry:Weather
Method of training a neural network using backpropagation. The error in the output of the neural network (e.g., a prediction of minimum nighttime temperature) is a function of the values of the input parameters (cloud cover, 6 temperature, etc. ) and the weights assigned to them. The weights are adjusted to minimize the error. Application of the delta rule results in the most rapid error reduction (learning rate). The learning rate can be adjusted as necessary to avoid being trapped in a local error minimum.
Industry:Weather
1. A region of diffluence in the atmosphere. 2. A region aloft beneath which low-level cyclogenesis is likely to occur. Compare exit region.
Industry:Weather
An approximate technique for handling the complexity of shortwave radiative transfer in anisotropically scattering atmospheres. The approximation is fairly accurate for transmitted and reflected irradiances provided the optical depth of the medium is greater than ≈ 3 and the absorption is weak. It is used mainly to speed up shortwave radiation computations in cloudy atmospheres.
Industry:Weather
The process of liquefaction of a solid by dissolution in solution resulting from absorbed water vapor. For atmospheric processes, the uptake of water by substances and dissolution at relative humidity generally present under atmospheric conditions. For example, LiCl (used to measure relative humidity by conduction current in older radiosondes) deliquesces at relative humidity in excess of 15%. The term hygroscopic refers to a similar process, although taking place at a higher relative humidity and a slower rate. For example, bulk sodium chloride is hygroscopic and dissolves slowly in relative humidity in excess of 76%.
Industry:Weather
Applied to any time-varying physical quantity, usually periodic, its displacement in time relative to a similar reference quantity. For example, the temperature in soil depends on depth and time. If the surface temperature varies sinusoidally, so does the temperature at any depth, but it is out of phase (is delayed) relative to the surface temperature. There is a phase shift or phase delay or phase lag of soil temperature relative to surface temperature. Although these three terms are most often applied to waves, nothing inherent in the concept of a delay restricts it to waves. Compare lag.
Industry:Weather
The removal of ice deposited on any object, especially applied to aircraft icing. Principal methods of de-icing in use today are heating, chemical treatment, and mechanical rupture of the ice deposit. Compare anti-icing.
Industry:Weather
A mechanical, electrical, or chemical means for removing ice, commonly from an aircraft. Mechanical deicers on aircraft deform the surface to remove accumulated ice by fracturing it. Electrical deicers remove ice by melting the bond between accumulated ice and the underlying surface. Chemical deicers lower the freezing temperature to prevent or remove ice from surfaces where they are applied, as on parked aircraft or runways.
Industry:Weather
