- Settore: 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, ...
A mercury barometer that is read by first bringing the free mercury surface in the cistern to a fixed level coincident with the zero of the scale.
Industry:Weather
A gradient, ∇xJ, of some scalar measure of a forecast, J, with respect to the vector of model control variables, x, that can include initial conditions, boundary conditions, and parameters. The inner product (δx, ∇xJ), where δx is a perturbation vector and ∇xJ is an adjoint sensitivity vector, provides δJ, a first-order (tangent linear) approximation to the difference, ΔJ, between an unperturbed nonlinear forecast and a nonlinear forecast with control variables perturbed by δx. See adjoint model, tangent linear equation, tangent linear approximation.
Industry:Weather
A form of variational data assimilation in which adjoint equations are used to obtain gradients of a scalar measure of a forecast (J) with respect to model control variables. The complete assimilation generally involves an iterative procedure to reduce the cost-function in which a minimization algorithm is used to adjust initial conditions based on a sensitivity gradient (∇xJ) provided by the adjoint model. See adjoint sensitivity, variational objective analysis.
Industry:Weather
A radar display on which targets appear as vertical deflections from a horizontal line that represents elapsed time from the most recent transmitted pulse. Distance to the target is indicated by the horizontal position of the deflection from the origin of the time axis; the amplitude of the vertical deflection is a function of the received signal strength. The A-display was the first type of radar display in common use. It may be produced by amplitude modulating the horizontal sweep of an oscilloscope with the received signal. An oscilloscope displaying this is called an A-scope. On an A-scope the difference between the coherent echoes produced by aircraft or ships and the rapidly fluctuating incoherent echoes from precipitation is readily apparent.
Industry:Weather
A thermodynamic system in which no heat or mass is transported across its boundaries.
Industry:Weather
Older expression for the process of lifting a parcel adiabatically on a thermodynamic diagram to ascertain when convective instability will occur.
Industry:Weather
The rate of change of temperature due to pressure under adiabatic conditions. In practice, since in the sea the pressure changes can be considered proportional to depth changes, the adiabatic temperature gradient is usually given as rate of change per unit depth, instead of per unit pressure. For practical purposes, the unit of depth is often chosen as 1000 m.
Industry:Weather
