- 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, ...
An experiment in which a model is assumed to represent the exact behavior of the physical system (the atmosphere) of interest. The model results are then sampled in a fashion to mimic some real or hypothetical observing system. OSSEs are an inexpensive way to guide the design of new or enhanced observing systems or to evaluate the usefulness of existing observations.
Industry:Weather
A group of meteorological observing stations spread over a given area for a specific purpose.
Industry:Weather
The difference between the true value of some quantity and its observed value. Every observation is subject to certain errors, as follows. 1) Systematic errors affect the whole of a series of observations in nearly the same way. For example, the scale of an instrument may be out of adjustment. These instrument errors can be detected and corrected by comparison with a standard. The personal equation of an observer may lead him to make small systematic errors in his readings; for example, if the scale is not at eye level. 2) Random errors, which appear in any series of observations, are generally small and as likely to be positive as negative; their magnitudes are usually distributed according to the error distribution. 3) Mistakes are widely discrepant readings.
Industry:Weather
Any 24-hour period selected as the basis for climatologic or hydrologic observations. Where observations are recorded automatically, the observational day is commonly taken as the calendar day. Where only one observation is made in 24 hours, the observational day is assumed to be the 24 hours ending at the time of observation.
Industry:Weather
A well drilled into an aquifer for the purpose of obtaining water level, water temperature, or water quality data.
Industry:Weather
Any collection of particles, aloft or in contact with the earth's surface, dense enough to be discernible to the observer. Examples are haze, dust, smoke, fog or ice fog, spray or mist, drifting or blowing snow, duststorms or sandstorms, dust whirls or sand whirls, and volcanic ash. Potentially, all hydrometeors and lithometeors may be obscuring phenomena.
Industry:Weather
1. In U. S. Weather observing practice, the designation for the sky cover when the sky is completely hidden by surface-based obscuring phenomena. It is encoded “X” in aviation weather observations; it always constitutes a ceiling, the height of which is the value of vertical visibility into the obscuring phenomenon. Compare partial obscuration. 2. A surface-based obscuring phenomenon.
Industry:Weather
The highest frequency that can be determined in a Fourier analysis of a discrete sampling of data. If a time series is sampled at interval Δ''t'', this frequency is 1/2Δ''t'' cps.
Industry:Weather
The greatest distance at which a specified target can be perceived when viewed along a line of sight inclined to the horizontal. One must distinguish upward from downward oblique visual range because of the quite different background luminance prevailing in the two cases. Furthermore, a range can only be considered with respect to some given type of target, as is also true of the ordinary (horizontal) visual range. In view of the great importance of the downward oblique visual range in air to ground visual contact and the upward oblique visual range in visual detection of aircraft, it is unfortunate that no satisfactory theory for this has yet been developed. The principal obstacle in treating this problem lies in the typically nonuniform height variation of the extinction coefficient.
Industry:Weather
