- 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, ...
The average of a predicted variable or field over an ensemble of forecasts. In taking the mean, one filters those aspects of the forecasts that are not predictable.
Industry:Weather
The average difference between the individual ensemble forecasts of a quantity and the ensemble mean forecast of the quantity. The ensemble spread is often used to predict the magnitude of the forecast error. See spread skill correlation.
Industry:Weather
A set of different forecasts all valid at the same forecast time(s). The differences between the forecasts can provide information on the probability distribution of the predicted variables. The forecasts in the ensemble may have different initial conditions, boundary conditions, parameter settings, or may even be from entirely independent NWP models.
Industry:Weather
1. The value of a meteorological variable found by averaging over many independent descriptions or realizations of that variable. While this type of average often forms the basis of theories and simulations (numerical or physical models) for turbulence, it is usually impossible to compute in real life because we cannot control the atmosphere in order to reproduce multiple ensemble members. In real life, an ergodic hypothesis is often used, where time or space averages are assumed to be reasonable approximations to ensemble averages. 2. In numerical weather prediction, the average found by averaging over many different forecasts for the same domain and time period, but starting from slightly different initial conditions or using different numerical models or parameterizations. This ensemble average is usually more accurate than any single model run because it partially counteracts the sensitive dependence to initial conditions associated with the nonlinear equations that govern the atmosphere.
Industry:Weather
In air navigation, abbreviation for “estimated time over next reporting position. ”
Industry:Weather
A mathematical function or set of tabulated values that can be used to process digital imagery to emphasize specific features or areas of interest.
Industry:Weather
An image that has had processing (e.g., contrast stretching, pseudocoloring, unsharp masking) applied to improve information presentation.
Industry:Weather
The additional greenhouse effect due to an increase in the concentration of greenhouse gases. Because of the complexity of the feedback processes within the climate system, the enhanced greenhouse effect is usually referred to in terms of the radiative forcing that results at the tropopause, after the stratosphere has come into a new radiative equilibrium. For example, thus defined, the enhanced greenhouse effect due to an effective doubling of carbon dioxide concentration from its preindustrial baseline is about 4 W m−2. Note the difference in meaning from the greenhouse effect, which refers to the entire natural process and which results in a climatological average counterradiation of about 330 W m−2 to the surface. A comparable value for the enhanced greenhouse effect at the surface will only be obtained once the new equilibrium temperature of the surface is known, since they are strongly interrelated.
Industry:Weather
A signature on infrared satellite imagery that depicts a warm, wedge-shaped region stretching from the upshear edge of a thunderstorm anvil, downshear along its long axis. This so-called warm wake is surrounded by long, narrow regions of colder pixels along either side, forming an apparent V shape. The warmer pixels may be stratospheric cirrus “blow-off” from overshooting tops, meaning that they are higher than the mean anvil height, even though they are warmer. The signature typically forms on convective storms possessing extremely strong updrafts.
Industry:Weather
