Fall velocity-
The particle falling speed, for any given object moving through a fluid medium of specified physical properties, at which the drag forces and buoyant forces exerted by the fluid on the object just equal the gravitational force acting on the object. The Particle falls at constant speed, unless it moves
into air layers of different physical properties.
Filnam-
The name of history data dump file. Input variable in ARPS NAMELIST file.
Finite difference approximation-
The difference between the values of a field at two discrete points, used to approximate the derivative of the function.
Friction velocity-
A reference wind velocity. It is usually applied to motion near the ground where the shearing stress is often assumed to be independent of height and approximately
proportional to the square of the mean velocity. The friction velocity is, therefore, exactly the velocity for which this square law would be valid.
First Guess at Analysis Time-
Also called the Background Field, the model state that is used to begin the weather analysis. Observation increments are first calculated by subtracting observed quantities from the first guess field, and the analysis is done as an increment to this field.
Flcmprs-
ADAS NAMELIST variable that indicates the desired level of compression for the history (model state output) files.
Forced wave-
Any wave that is required to fit irregularities at the boundary of a system or satisfy some impressed force within the system. The forced wave will not in general be a characteristic mode of oscillation of the system. It cannot be exhibited independently unless the system admits no free waves. A homogeneous incompressible fluid bounded by two rigid surfaces is an example of such a system.
The gravity lee wave in the atmosphere is an example of mixed forced and free waves.
Free parameter-
A numerical value in a structural model that is part of the model, but is not fixed at any particular value by the model hypothesis. Free parameters are estimated by the program using interactive methods.
