- 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, ...
1. See instrument error, observational error, random error, systematic error, standard error. 2. See forecast error.
Industry:Weather
“One of a series of small ridges on a snow surface formed by the corrasive action of wind-blown snow. “Erosion ridges may be formed either at right angles to the wind or aligned with the wind. ” (Glossary of Arctic and Subarctic Terms 1955. ) Compare sastruga.
Industry:Weather
The movement of soil or rock from one point to another by the action of the sea, running water, moving ice, precipitation, or wind. Erosion is distinct from weathering, for the latter does not necessarily imply transport of material. Where human agency has increased erosion beyond the normal geologic rate, it is termed accelerated erosion. Wind erosion is a very important factor in the continued redistribution of earth surface material. Two measures of this effect are used by geologists, capacity of the wind and competence of the wind. Compare corrasion, corrosion, eolation.
Industry:Weather
For turbulent flow, the property of having the spatial, temporal and ensemble averages all converge to the same mean. This can only be true if the flow is stationary and homogenous. As a consequence, the autocorrelation of an ergodic flow variable is zero as either the averaging length, time, or number of realizations goes to infinity. See ensemble average.
Industry:Weather
In Mexico, during October to January, heavy, cold rains that last for several days.
Industry:Weather
An idealized atmospheric state where the ensemble average equals both the time and spatial averages. While most turbulence theories are based on the ensemble average, most calculations of averages in the real atmosphere are averages over time of a fixed point, or averages over a line or a volume at an instant in time (i.e., a snapshot). By making the assumption ergodic, values measured in the real atmosphere can be utilized within the Reynolds averaged equations for turbulent flow.
Industry:Weather
A system in which the time mean of every measurable function of the system equals its space mean. For example, isotropic homogeneous turbulence is often assumed to be ergodic, that is, the time mean at any given moment (e.g., velocity or velocity variance) coincides with the spatial mean.
Industry:Weather
The region of the ionosphere usually found at an altitude between 100 and 120 km. It exhibits one or more distinct maxima and sharp gradients of free electron density. It is most pronounced in the daytime but does not entirely disappear at night. Ionosonde recordings show that the E-region is often subdivided into two or more “E-layers,” while localized and intermittent regions of fairly high ionization, known as sporadic E-layers, are also frequently observed. The E- region is produced by absorption of solar radiation at a variety of extreme ultraviolet (EUV) and x-ray wavelengths.
Industry:Weather
The unit of energy in the centimeter–gram–second system of physical units, that is, one dyne-centimeter. One erg is equal to 10−7 joule or to 2. 389 × 10−8 cal.
Industry:Weather
