- 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, ...
In England, the number of Fahrenheit degrees that the temperature falls below the freezing point. Thus a day with a minimum temperature of 27°F may be designated as a day of five degrees of frost. Compare degree-day.
Industry:Weather
In an unconstrained dynamic or other system, the number of independent variables required to specify completely the state of the system at a given moment. If the system has constraints, that is, kinematic or geometric relations between the variables, each such relation reduces by one the number of degrees of freedom of the system. In a continuous medium with given boundary conditions, the number of degrees of freedom is the number of normal modes of oscillation. Thus, a particle moving in space has three degrees of freedom; an incompressible fluid with a free surface has an infinite number of degrees of freedom.
Industry:Weather
As used by U. S. Army Corps of Engineers, the departure (in °F) of the hourly temperature from a standard of 32°F, positive if above and negative if below. Degree-hours may be accumulated (summed) over any period of time, depending upon the use to which they are applied. Compare degree-day.
Industry:Weather
1. Generally, a measure of the departure of the mean daily temperature from a given standard: one degree-day for each degree (°C or °F) of departure above (or below) the standard during one day. Degree-days are accumulated over a “season” at any point during which the total can be used as an index of past temperature effect upon some quantity, such as plant growth, fuel consumption, power output, etc. This concept was first used in connection with plant growth, which showed a relationship to cumulative temperature above a standard of 5°C (41°F). Recently, degree-days have been more frequently applied to fuel and power consumption, for example, heating degree- day, cooling degree-day. In the life sciences, the standard is often referred to as the base temperature or upper threshold, depending on whether the standard is used as a lower or upper limit, respectively. As used by the U. S. Army Corps of Engineers, Fahrenheit degree-days are computed as departures above and below 32°F, positive if above and negative if below. To avoid confusion, it might be well to call this a “freezing degree-day. ” The advantages and disadvantages of the latter concept are discussed well by Sakari Tuhkanen (1980). Compare degree-hour. 2. Common contraction for heating degree-day.
Industry:Weather
The proportion of the pores in a soil filled with water. It is equal to the volume of water divided by the volume of the pores and is often expressed as a percent.
Industry:Weather
1. The ratio of polarized to total radiance in some direction. The degree of polarization ranges from 0 percent for unpolarized radiation, typical of direct solar radiation, diffuse solar radiation within clouds, and all terrestrial infrared radiation, to 100% for completely polarized radiation. The degree of polarization of light from a Rayleigh atmosphere with minimal turbidity is close to 100% at a scattering angle of 90°. 2. See polarization.
Industry:Weather
1. A unit of temperature. See absolute temperature scale, Celsius temperature scale, centigrade temperature scale, Fahrenheit temperature scale, Kelvin temperature scale, Reaumur temperature scale. 2. A unit of angular distance; 1/360 part of a circle.
Industry:Weather
The lessening of a quality of data or images because of any optical, electronic, or mechanical distortions (noise) in the data collection or image forming systems.
Industry:Weather
A terrestrial point on a tidal chart from which cotidal lines appear to radiate. An imaginary point where nothing happens.
Industry:Weather
A general term for sea ice that has been broken and reoriented. It includes ridged, hummocked, and rafted ice. Deformed ice is distinguished by its high surface roughness.
Industry:Weather
