Kenneth R. Hardy

Radar and sodar probing of waves and turbulence in statically stable clear-air layers

This paper reviews the remote sensing of waves and turbulence in statically stable atmospheric layers, utilizing sodar and microwave radar echoes from the small-scale inhomogeneities in gaseous refractive index caused by localized fluctuations in temperature, humidity, and velocity. Scattering theory and sounding methodology are reviewed briefly, and the relative performance of typical radar and sodar systems compared. The main section of the paper takes the form of a summary and discussion of experimental progress since 1969, showing how the echo patterns obtained may be applied to the interpretation of multiple layering, gravity waves, internal fronts and the details of dynamic instability and the genesis of turbulence in stably stratified shear layers. In addition, methods for the measurement of the intensity of the small-scale (∼ λ/2) variability of wind, temperature and water vapor from the observed radar or sodar echo intensities, and the use of Doppler techniques for the measurement of mean velocity and turbulence are discussed.

Tropopause Detected by Radar

The tropopause has been detected by ultrasensitive, narrow-beam, microwave (10.7-centimeter) and ultrahigh-frequency (71.5-cm) radars. Its reflectivity is consistent with that expected theoretically for a refractively turbulent medium. Indications are that the layer is also mechanically turbulent, and that electromagnetic scatter techniques may be used to detect high-altitude clear-air turbulence.

Further study of the atmospheric gravity waves over the eastern seaboard on 18 March 1969

Abstract Washington, D. C., microbarograph records for 18 March 1969 reveal gravity-wave-associated pressure oscillations which appear to be directly related to upper tropospheric wave structure observed at the same time with a Wallops Island 10-cm wavelength radar. The consistency between the two sets of data provides new observational support for a hypothesis of long standing in the microbarograph community; namely, that shear instability in the upper tropospheric flow is indeed the mechanism responsible for the generation of such waves. The comparison presented here suggests that microbarograph arrays might be useful adjuncts to future radar studies of upper tropospheric wave dynamics, supplying such wave parameters as phase velocity and wavelength in favorable cases. A closer examination of the radar data pertinent to this event reveals an apparent vertical wave phase variation, permitting a very approximate and somewhat uncertain estimate of the wave-associated vertical flux of horizontal momentum, w...

Radar Investigations of Atmospheric Structure and CAT in the 3 to 20-km Region

Sensitive radars regularly detect thin horizontal layers in the clear atmosphere. The radar backscattering from these clear-air regions is related to the degree of turbulence and to the mean gradient of potential refractive index. A qualitative description of the atmospheric structure which may exist in regions of CAT is given and arguments are presented to indicate that the radar backscattered signal intensity will be at least a crude estimate of the intensity of high altitude CAT.

Applications of radar to meteorological operations and research

Radar echoes from meteorological targets have existed almost from the time that radar was first used. In this paper, an equation is presented which relates the echo power to a characteristic of the cloud or precipitation particles within the radar pulse volume. Some examples of how radar has been used for operational purposes are given; these include a description of the utility of radar for storm detection, how radar can be used as an aid to weather forecasting for both the public and aviation interests, and also how radar can be applied to help solve some hydrological problems. Significant research results on the nature of atmospheric structure and processes as derived with the help of radar are presented. Doppler radar has played a prominent role in the investigation of storm dynamics, and high-power high-resolution radars have been used for studying the development and nature of clear-air turbulence and convective processes in the clear air. Recent trends in meteorological radars are indicated and suggestions are set forth which relate to the improved use of radar for operations.

Simultaneous radar, aircraft and meteorological investigations of clear air turbulence.

Abstract The results of simultaneous studies of clear air turbulence (CAT) in the lower 15 km of the atmosphere by multi-wavelength radar, jet aircraft and special rawinsondes at the JAFNA radar facility at Wallops Island, Va., are reported. The most important finding is that for the particular aircraft and velocity used in these experiments, every clear air radar echo above 3 km is associated with aircraft reports of at least some perceptible degree of turbulence. Between the altitudes of 3 and 6 km, all CAT is detected by the radars; however, the ability of the radars to detect weak CAT decreases with increasing altitude and only the more intense turbulence is detected above 12 km. The indications are that strong CAT at high altitudes in the free atmosphere is generally associated with zones of increased refractive index variability and enhanced radar backscattering. Therefore, if radars of extreme sensitivity are employed, the useful range for CAT detection may be extended considerably and may possibly...

Clear-air turbulence - Simultaneous observations by radar and aircraft.

Ultrasensitive radars and uninstrumented jet aircraft in concert have probed regions of the clear atmosphere in search of clear-air turbulence. All sources of clear-air radar echoes above 6 kilometers that were probed simultaneously by the aircraft were found to be turbulent.

Assessing Prejudice Toward Negroes at Three Universities Using the Lost-Letter Technique.

The lost-letter technique was used to assess attitudes toward Negroes at Brigham Young University as compared to Arizona State University and the University of Cincinnati. 200 letters were “lost” at each school, half addressed to the “Medical Research Association,” half to the “Negro Equal Rights Movement.” Findings showed that B. Y. U. students acted most responsibly (highest return rate), but such behavior was significantly attenuated by prejudice (fewer Negro than Medical returns). A. S. U. students, contrastingly, were least responsible but were relatively unaffected by prejudice. Cincinnati students were similar to B. Y. U. students in prejudice, but more like Arizona students on level of responsibility. Difficulties in interpretation are partly based on the inadequacies of the lost-letter technique used as a non-reactive measure.

SEXUAL APPETITE AND SEXUAL DRIVE: A REPLY

A reply is made to a critique of the authors previous paper, centering about two major issues: (1) theoretical precision and objectivity and (2) contamination of theory with values. Response is also given to a variety of specific criticisms.