- 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, ...
Application of the concepts and methods of dynamics (a branch of physics) to the ocean; the study of the effects of dynamical forces on ocean behavior, motion, and water properties. The term “dynamic method“ is used to describe a method whereby the baroclinic component of the geostrophic current is estimated through measurements of density structure.
Industry:Weather
1. The height of a point in the atmosphere expressed in a unit proportional to the geopotential at that point. Since the geopotential at altitude z is numerically equal to the work done when a particle of unit mass is lifted from sea level up to this height, the dimensions of dynamic height are those of potential energy per unit mass. The standard unit of dynamic height is the dynamic meter (or geodynamic meter). One of the practical advantages of the dynamic height over the geometric height is that when the former is introduced into the hydrostatic equation the height acceleration of gravity is eliminated. In meteorological height calculations geopotential height is more often used than dynamic height. In oceanography, dynamic computations are also based upon units of dynamic height (or dynamic depth). 2. In oceanography, represents the ability of a column of water to do work due to differences in geopotential (the potential for gravity to do work because of height of the water relative to some reference level). The dynamic height is computed from the measured density distribution. Geopotential height differences, expressed by changes in dynamic topography, are a measure of the horizontal pressure gradient force.
Industry:Weather
The standard unit of dynamic height, defined as 10 m2 s−2; it is related to the geopotential φ, the geometric height z in meters, and the geopotential height Z in geopotential meters by
where g is the acceleration of gravity in meters per second squared. (Some sources prefer to give the constants 10 and 9. 8 the units of meters per second squared so that the units of φ and Z would be the same as those of the geometric height. )
The dynamic meter is about 2% longer than the geometric meter and the geopotential meter.
Industry:Weather
The study of atmospheric motions as solutions of the fundamental equations of hydrodynamics or other systems of equations appropriate to special situations, as in the statistical theory of turbulence. The restrictions of this definition suffice to distinguish dynamic meteorology from other fields, for example, physical meteorology or synoptic meteorology, such distinctions being a function of the state of the science rather than of the subject matter itself.
Industry:Weather
A procedure that adjusts the initial conditions of an NWP model so that unwanted high-frequency oscillations are removed. The procedure requires that the NWP model be integrated forward and backward around the initial time using a heavily damped finite-difference equation.
Industry:Weather
1. The height of a point in the atmosphere expressed in a unit proportional to the geopotential at that point. Since the geopotential at altitude z is numerically equal to the work done when a particle of unit mass is lifted from sea level up to this height, the dimensions of dynamic height are those of potential energy per unit mass. The standard unit of dynamic height is the dynamic meter (or geodynamic meter). One of the practical advantages of the dynamic height over the geometric height is that when the former is introduced into the hydrostatic equation the height acceleration of gravity is eliminated. In meteorological height calculations geopotential height is more often used than dynamic height. In oceanography, dynamic computations are also based upon units of dynamic height (or dynamic depth). 2. In oceanography, represents the ability of a column of water to do work due to differences in geopotential (the potential for gravity to do work because of height of the water relative to some reference level). The dynamic height is computed from the measured density distribution. Geopotential height differences, expressed by changes in dynamic topography, are a measure of the horizontal pressure gradient force.
Industry:Weather
A thermodynamic variable similar to potential temperature, except that the concept of static energy assumes that any kinetic energy is locally dissipated into heat. The amount of this dissipative heating is often negligible. When dry static energy, s, is expressed in units of kJ kg−1, the resulting values are of order 300 kJ kg−1, which reinforces the analogy with potential temperatures in units of Kelvin. Dry static energy is conserved during unsaturated vertical and horizontal motion, and is defined as
where cp is the specific heat capacity of air at constant pressure, T is absolute temperature, g is gravitational acceleration, and z is height. The reference height can be arbitrary; it is sometimes taken as z = 0 at P = 100 kPa to be consistent with potential temperature, or it can be defined relative to the local ground or sea level. Compare moist static energy, liquid water static energy, saturation static energy.
Industry:Weather
Transport of a quantity, expressed in units of that quantity crossing a unit area per unit time. Examples are heat flux in units of J m−2 s−1 (equivalent to W m−2), momentum flux in units of kg (m s−1)(m2 s)−1 (equivalent to kg m−1 s−2), or mass flux in units of kg m−2 s−1. When a flux in dynamic units is divided by air density (or for heat flux by air density times specific heat of air at constant pressure), the result is the flux in kinematic units, which is often easier to measure by conventional weather instruments such as anemometers and thermometers.
Industry:Weather
The statistical collation and study of observed elements (or derived parameters) of the atmosphere, particularly in relation to the physical and dynamical explanation or interpretation either of the contemporary climate patterns with their anomalous fluctuations or of the long-term climate changes or trends.
Industry:Weather
