Irregularities and irregular motions in the upper atmosphere have been detected and studied by a variety of techniques during recent years, but their proper interpretation has yet to be established...

Internal atmospheric gravity waves at ionospheric heights

From the Publisher:
Adaptive Filtering: Algorithms and Practical Implementation is a concise presentation of adaptive filtering, covering as many algorithms as possible while avoiding adapting notations and derivations related to the different algorithms. Furthermore, the book points out the algorithms which really work in a finite-precision implementation, and provides easy access to the working algorithms for the practicing engineer. Adaptive Filtering: Algorithms and Practical Implementation may be used as the principle text for courses on the subject, and serves as an excellent reference for professional engineers and researchers in the field.

Adaptive Filtering: Algorithms and Practical Implementation

Simulated annealing: Practice versus theory

This paper reviews analytical methods in electromagnetic scattering theory (i.e., geometrical and physical optics, perturbation, iteration, and integral-equation) which are applicable to the problems of remote sensing of the ocean. In dealing with Earth's surface (in this case, the weakly non-linear ocean), it is not possible to have a complete and exact description of its spatial and temporal statistics. Only the first few moments are generally available; and in the linear approximation the statistics are assumed homogeneous, stationary and Gaussian. For this case, the high-frequency methods (geometrical and physical optics) and perturbation (Rayleigh-Rice), or a combination of them, provide tractable analytical results (i.e., the specular-point, the slightly-rough Bragg scattering and the composite-surface models). The applicability and limitations of these models are discussed. At grazing incidence and for higher frequencies, other scattering mechanisms become significant; and shadowing, diffraction and trapping must be considered. The more exact methods (integral-equation and Green's function) have not been as successful in yielding tractable analytical solutions, although they have the potential to provide improved theoretical scattering results in the future.

Theories for the interaction of electromagnetic and oceanic waves — A review

From observations of wind and of water surface elevation at 14 wave staffs in an array in Lake Ontario and in a large laboratory tank, the directional spectrum of wind-generated waves on deep water is determined by using a modification of Barber's (1963) method. Systematic investigations reveal the following: (a) the frequency spectrum in the rear face is inversely proportional to the fourth power of the frequency $\omega $, with the equilibrium range parameter and the peak enhancement factor clearly dependent on the ratio of wind speed to peak wave speed; (b) the angular spreading $\theta $ of the wave energy is of the form sech$^{2}$ ($\beta \theta $), where $\beta $ is a function of frequency relative to the peak; (c) depending on the gradient of the fetch, the direction of the waves at the spectral peak may differ from the mean wind direction by up to 50 degrees, but this observed difference is predictable by a similarity analysis; (d) under conditions of strong wind forcing, significant effects on the phase velocity caused by amplitude dispersion and the presence of bound harmonics are clearly observed and are in accordance with the Stokes theory, whereas (e) the waves under natural wind conditions show amplitude dispersion, but bound harmonics are too weak to be detected among the background of free waves.

Directional spectra of wind-generated waves

The concept of transform domain adaptive filtering is introduced. In certain applications, filtering in the transform domain results in great improvements in convergence rate over the conventional time-domain adaptive filtering. The relationship between several existing frequency domain adaptive filtering algorithms is established. Applications of the discrete Fourier transform (DFT) and the discrete cosine transform (DCT) domain adaptive filtering algorithms in the areas of speech processing and adaptive line enhancers are discussed.

Transform domain LMS algorithm

Wave directional spectra from synthetic aperture observations of radio scatter

A new technique for remote measurement of temperature in the lower atmosphere has been developed and successfully tested The equipment used is called a Radio Acoustic Sounding System because a burst of sound propagating upward in the air is tracked by a Doppler radar Air temperature at each height is determined from the instantaneous speed of the sound pulse and a complete profile can be obtained in only a few seconds In order to improve accuracy, the measurements are normally averaged for several minutes, but even so the sampling rate is high enough to continuously monitor the temperature profile Although earlier efforts showed that sound could indeed be tracked by radar, the work described here is the first successful attempt to use the technique to measure temperature profiles

RASS, a remote sensing system for measuring low-level temperature profiles

A method is developed for measuring the velocity of winds in the 90- to 110-kilometer height region of the upper atmosphere. From the Doppler frequency shift imparted to a continuous-wave reflection from a meteoric ionization column, a measure of the wind drift of the trail is found. Statistical analysis enables average wind velocities to be measured to within perhaps 20 per cent, and direction to 20°, in a period of one or two hours. Observations made during the early morning hours in the summer of 1949 show typical average wind velocities to be 125 kilometers per hour, with motions from south-southwest and north the most common. On some occasions, evidence of a nonuniform wind structure is found.

http://ieeexplore.ieee.org/iel5/10933/35840/01701348.pdf

Meteoric Echo Study of Upper Atmosphere Winds

Continuous-wave signals transmitted from Lunar Orbiter I have been received on Earth after they have been reflected from the surface of the moon. The frequency spectrum of the reflected signals is used to locate discrete, heterogeneous, scattering centers on the lunar surface. The scattering centers are probably distinguished from the surrounding terrain by a higher surface reflectivity. Continuous-wave bistatic radar could provide an important new method for the study and mapping of planetary surfaces.

https://science.sciencemag.org/content/sci/157/3785/193.full.pdf

A. M. Peterson

Papers

Transform domain LMS algorithm

Wave directional spectra from synthetic aperture observations of radio scatter

RASS, a remote sensing system for measuring low-level temperature profiles

Meteoric Echo Study of Upper Atmosphere Winds

Bistatic-radar detection of lunar scattering centers with lunar orbiter I.