A review of radar studies of the middle atmosphere

Abstract

This paper reviews radar studies of the middle atmosphere at VHF and UHF frequencies. The mechanisms responsible for the scattering at both stratospheric and mesospheric heights are qualitatively discussed, and an attempt is made to evaluate the potential of the technique for inferring atmospheric parameters. A few applications of the technique to the study of atmospheric dynamics are then presented. Finally, some recommendations are made for future work.

A review of radar observations of turbulence in the lower stratosphere

“…This is one of three review papers in this special issue devoted to radar observations of the clear atmosphere; Harper and Gordon [1980] consider studies of the middle atmosphere including the stratosphere; James [1980] reviews observations in the troposphere; and we address the interpretation of radar observations in the region about the tropopause. Historically, Atlas et al [1966] were the first to report radar detection of the tropopause using the radars at Wallops Island.…”

“…To date, most of the observations have been morphological in nature, exploring the occurrence and motion of turbulence in the lower stratosphere. Examples of wind profile observations, short-period gravity wave perturbations of the wind profile, and the anisotropy of turbulence in stably stratified regions of the lower stratosphere have been reported (see Harper and Gordon [ 1980] or Gage and Balsely [1978], for example). Applications of radar observations to the estimation of the intensity of turbulence as described by the small-scale turbulent eddy dissipation rate have been reported by Crane [1977] and by Green et al [1978a].…”

“…The focus of this review paper is the use of radar for estimating the intensity of turbulence rather than the motion of the turbulence. Application of radar systems to the observation of air motion is presented in the review papers by Harper and Gordon [1980] and by James [1980]. Consideration is also given to the problem of estimating the intensity of the refractive index fluctuations given the average gradients of temperature and horizontal wind velocity in the lower stratosphere.…”

The Moon as a calibration target of convenience for VHF‐UHF radar systems

“…It is often convenient and even necessary to verify the performance of a radar system in an absolute sense. An example of current interest involves the so-called ST or MST (mesospheric, stratospheric, tro pospheric) radars [Harper and Gordon, 1980] for which absolute scattering cross sections per unit volume from these atmospheric regions could prove valuable [e.g., Rottger, 1980;Hocking et al, 1986].…”

Atmospheric radar for the 0.5-110 km region

“…Thermal (also known as Incoherent or Thomson) will not be discussed further here (for reviews see [1] and [2]). Turbulent (or Bragg) scatter results from the production of irregularities in refractive index by turbulence, for which the dominant Fourier scales correspond to half the projection of the wavelength of the radar onto the radiowave vector.…”