CAT-generating mechanisms

The development of instability configurations; the transition from unstable growth of these configurations into turbulence; a description of the nature of that turbulence; the question of decay of turbulence; and the existence of what is called fossil turbulence are discussed

The transient development of a lee wave

A stream with an initially undisturbed free surface is set impulsively in motion and a (small) pressure perturbation is applied to the surface. The form of the free surface as a function of time is examined in detail up to the point where the disturbance is sensibly that of a steady-state lee wave

Transparency of Magnetized Plasma at Cyclotron Frequency

Electromagnetic radiation is strongly absorbed by the magnetized plasma if its frequency equals the cyclotron frequency of plasma electrons. It is demonstrated that absorption can be completely canceled in the presence of a second radiation beam, or even a magnetostatic field of an undulator, resulting in plasma transparency at the cyclotron frequency. This effect is reminiscent of the electromagnetically-induced transparency (EIT) of the three-level atomic systems, except that it occurs in a completely {\it classical} plasma. Also, because of the complexity of the classical plasma, index of refraction at cyclotron frequency differs from unity. Potential applications of the EIT in plasma include selective plasma heating, electromagnetic control of the index of refraction, and electron/ion acceleration

First global analysis of SEASAT scatterometer winds and potential for meteorological research

The first global wind fields from SEASAT-A scatterometer (SASS) data were produced. Fifteen days of record are available on tape, with unique wind directions indicated for each observation. The methodology of the production of this data set is described, as well as the testing of its validity. A number of displays of the data, on large and small scales, analyzed and gridded, are provided

A new parameterization of an empirical model for wind/ocean scatterometry

The power law form of the SEASAT A Scatterometer System (SASS) empirical backscatter-to-wind model function does not uniformly meet the instrument performance over the range 4 to 24 /ms. Analysis indicates that the horizontal polarization (H-Pol) and vertical polarization (V-Pol) components of the benchmark SASS1 model function yield self-consistent results only for a small mid-range of speeds at larger incidence angles, and for a somewhat larger range of speeds at smaller incidence angles. Comparison of SASS1 to in situ data over the Gulf of Alaska region further underscores the shortcomings of the power law form. Finally, a physically based empirical SASS model is proposed which corrects some of the deficiencies of power law models like SASS1. The new model allows the mutual determination of sea surface wind stress and wind speed in a consistent manner from SASS backscatter measurements

Perturbations of the Richardson number field by gravity waves

An analytic solution is presented for a stratified fluid of arbitrary constant Richardson number. By computer aided analysis the perturbation fields, including that of the Richardson number can be calculated. The results of the linear analytic model were compared with nonlinear simulations, leading to the following conclusions: (1) the perturbations in the Richardson number field, when small, are produced primarily by the perturbations of the shear; (2) perturbations of in the Richardson number field, even when small, are not symmetric, the increase being significantly larger than the decrease (the linear analytic solution and the nonlinear simulations both confirm this result); (3) as the perturbations grow, this asymmetry increases, but more so in the nonlinear simulations than in the linear analysis; (4) for large perturbations of the shear flow, the static stability, as represented by N2, is the dominating mechanism, becoming zero or negative, and producing convective overturning; and (5) the convectional measure of linearity in lee wave theory, NH/U, is no longer the critical parameter (it is suggested that (H/u sub 0) (du sub 0/dz) takes on this role in a shearing flow)