Advective Boundary Layer-
Aerodynamic Roughness Length-
(Also called the roughness length, z0.) The height above the
displacement plane at which the mean wind becomes zero when extrapolating the
logarithmic wind- speed profile downward through the surface layer.It is a
theoretical height that must be determined from the wind-speed profile, although
there has been some success at relating this height to the arrangement, spacing,
and physical height of individual roughness elements such as trees or
houses.
Aitken Particles-
Aerosol particles below 0.1 mm in diameter. These generally are
the most numerous among all particles in the air. Their concentrations can be
determined with the Aitken counter which measures total particle number density.
Owing to their small size, Aitken particles contribute little to the total mass
concentration of all aerosol particles this is determined primarily by particles
of diameter greater than 0.1 mm.
Albedo- Fraction expressing the portion of incident short wave radiation that is reflected from the surface. Albedo is dependent on soil type and color, vegetation fraction and vegetation color. In the context of remote sensing the albedo can be expressed in terms of the amount of radiation reflected from the top of atmosphere, and this will include effect of clouds.
Atmospheric Window-
A range of wavelengths over which there is relatively little absorption of radiation by atmospheric gases. The major windows are the visible window, from -0.3 to -0.9 micro m; the infrared window, from -8 to -13 micro m; and the microwave window, at wavelengths longer than -1 mm. The infrared window loses much of its transparency under very humid conditions due to continuum absorption by water vapor, and can become completely opaque when clouds are present.
Advanced Regional Prediction System Data
Assimilation System- ADAS is a 3-dimensional
weather analysis program. The analysis method is a successive correction scheme
known as the Bratseth method [Tellus, 1986]. This method is designed to
asymptotically approach the result of a statistical (optimal)
interpolation.
Advanced Regional Prediction System-
(ARPS) A non-hydrostatic multi-scale numerical weather prediction system on a terrain-following coordinates system developed by the Center for the Analysis and Prediction of Storms (CAPS).
