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Developing a rationale and implementing research strategies for the vocational evaluation process is vital for rehabilitation personnel. (Author/AG)

Statistical summaries are presented of computed values of parameters appearing in a modification of Sutton's diffusion equations. Experimental data used for the computations are those obtained during Project Prairie Grass at O'Neill, Nebraska and those obtained at Round Hill, Massachusetts. Stratification of the parameters ny and nz according to stability class reveals systematic variations of class-median values of ny and nz with stability class and a large range of ny and nz within any given stability class. No difference in the results was found between the two sets of experiments for these parameters. The parameter, Cy, has a mean value of about 0.4 for the Prairie Grass experiments and about 0.9 for the Round Hill experiments. No relationship between Cy and stability was found for the Prairie Grass experiments, but a correlation coefficient of 0.22 between Cy and stability ratio was found for the Round Hill experiments. The parameter, Cz, computed only for the Prairie Grass experiments, has ...

The temperature of a thin turbid layer above the ground is expressed as a function of time by considering the processes of nocturnal radiation and eddy conduction. It is found that under certain conditions the layer will cool until the lapse rate below the turbid layer becomes unstable. It is suggested that vertical mixing then may transform the thin layer into a thick layer extending to the ground. At the same time increased stability above the turbid layer may result in a sharply defined upper boundary. The temperature distribution in a thick turbid layer is found to depend on the free-air and ground temperatures (treated as constants), the infra-red absorptivity of the layer, and the eddy conductivities within and above the layer. If certain critical conditions are satisfied, the lapse rate within the turbid layer will become unstable and the lapse rate within the non-turbid air will become stable. Observations of the vertical temperature distribution before and after fog formation support thi...

In the Green Glow program conducted near Richland, Washington, during the summer of 1959, 26 diffusion experiments were conducted during nocturnal inversions. The tracer was released near ground level. Samplers were placed at 1.5 m above ground at 533 positions on six sampling arcs, the radii of which were 200 m, 800 m, 1.6 km, 3.2 km, 12.8 km, and 25.6 km. In addition to the ground sampling network, poles or towers were erected at five points, 8 deg apart, on each of the four inner arcs. Fifteen samplers were mounted on each pole or tower, the top level increasing from 27 m on the 200 m arc to 62 m on the 1.6 km and 3.2 km arcs. The vertical measurements of tracer dosage made during Experiment No. 3 suggest that during this experiment, conducted during one of the stronger inversions, the mean wind direction changed significantly with height in the lowest 200 ft. Direct measurements of mean wind direction confirm this notion. A diffusion model is discussed in which the tracer dosage at a point do...

The 1428-lt television transmitter tower, located at Cedar Hill, Texas, and instrumented to obtain continuous measurements of wind and temperature at 12 levels from 30 ft to 1420 ft above ground, is proving to be a useful research tool for investigating low-level meteorological phenomena, especially the low-level jet. During the night of 22–23 February 1961, a pronounced low-level jet was recorded. Systematic variations of wind speed and temperature with time and height will be discussed to illustrate the orderly development of the low-level jet, the upward growth of the nocturnal inversion, and the vertical extent of the mixing process within the deepening inversion.

During the summer of 1959, the Green Glow program, consisting of 26 diffusion experiments during nocturnal inversions, was conducted at the Atomic Energy Commission's Hanford Site near Richland, Wash. The tracer, zinc sulfide, was released near ground level. Samplers were placed at 1.5 m above ground at 533 positions on six sampling arcs, the radii of which were 200 m, 800 m, 1.6 km, 3.2 km, 12.8 km, and 25.6 km. In addition to the ground sampling network, poles or towers were erected at 5 points, 8 deg apart, on each of the 4 inner arcs. Fifteen samplers were mounted on each pole or tower, the top level increasing from 27 m on the 200-m arc to 62 m on the 1.6-km and 3.2-km arcs. General aspects of the experimental design and tracer technique are discussed along with terrain characteristics and meteorological conditions pertinent to these experiments. Experimental results are presented showing the increase in horizontal plume width and decrease of maximum exposure with distance from the source. A...

Wind tunnel and field experiments have shown that the fast-response three-component sonic anemometer is a highly accurate wind speed sensor. When sonic anemometers were used as reference sensors for wind speed, slower response cup anemometers were found to consistently overestimate the wind speed. Despite measures taken during a field program in Kansas to minimize tower influence on wind measurements, the errors due to the tower effect on the windward side are inferred to be about ±5% of the observed wind speed ratios of cup to sonic anemometers. When the observed speed ratios are compared with the errors due to tower influence, the overspeeding of the cup anemometer is estimated to be about 10% of the reference wind speed.

The issue of work inhibition is of prime concern to rehabilitation personnel. A review of the literature suggests that work and work adjustment services may be of some value in facilitating behavior change, and in generating meaningful vocational involvement for a disabled and disadvantaged population. A rationale in support of work as therapy is presented, along with an examination of some major limitations to the approach.

Micrometeorological measurements made during Project Prairie Grass have been used in an examination of a theoretical model proposed by Swinbank to describe wind speed profiles in the lower portion of the atmospheric boundary layer during conditions of non-neutral temperature stratification. In the derivation of the Swinbank hypothesis the Monin-Obukhov length, L, is employed. The derivation depends upon an assumption that L is constant in the lower boundary layer. The analysis of the observational data, however, reveals a systematic increase of 1/L with height during lapse conditions and a systematic decrease of 1/L with height during inversion conditions. Unsuccessful attempts to explain these variations of 1/L with height are discussed. It is concluded that the Swinbank hypothesis is not verified by the micrometeorological data of Project Prairie Grass.

Sutton's hypothesis for diffusion from a continuous point source has been evaluated using the data obtained during Project Prairie Grass. It is found that the hypothesis predicts the observed concentration distributions only if there are two values of Sutton's “n”, one to characterize lateral diffusion (ny) and one to characterize vertical diffusion (nz). Statistical tests indicate that ny and nz are invariant with distance between 100 and 800 m of the source, but that the values of ny and nz appropriate for these distances exceed the values within 100 m of the source. It is also shown that neither ny nor nz can be specified by nw1, the value of n found from a power-law fit to the wind profile in the lowest 8 meters.

Project Prairie Grass was a field program designed to provide experimental data on the diffusion of a tracer gas over a range of 800 meters. In each of 70 experiments the gas was released continuously for 10 minutes at a source located near ground level. The gas releases were made over a flat prairie in Nebraska under a variety of meteorological conditions during July and August of 1956. A brief history of the project is included with detailed descriptions of the tracer technique and the meteorological equipment employed in the field program. Tabulations of the diffusion data and the meteorological data collected during the gas releases are also presented. In addition, data is presented on the heat budget at the air-earth interface during other selected periods during the summer of 1956.

Smoke plumes emitted from elevated sources during inversion conditions and characterized by negligibly small settling rates remain aloft for many miles over fairly flat terrain. Photographs of oil-fog plumes taken at the Brookhaven National Laboratory are presented to show the non-isotropic character of diffusion during conditions of strong stability.

Survey Group on Meso-micrometeorology outlines its recommendation that a facility be established which would develop, acquire, maintain and operate certain types of meteorological instruments and supporting data-handling facilities. Included in the report is a general Description of problem areas, problems in Mesometeorology and Micrometeorology, comparison of existing and planned facilities, recommended instrumentation, a timetable and an example of an essential problem for which the facility is needed.

The GREEN GLOW program was a field investigation aimed at providing experimental data on the diffusion of an aerosol over a 16-mile range. The experiments, 26 in number and all during nighttime hours, were conducted on the Hanford reservation of the U. S. Atomic Energy Commission, near Richland, Washington during the Summer of 1959. Descriptions of the field site, forecasting techniques, diffusion-measuring methods, meteorological equipment, and operating procedures during the experiments are given.

The Taylor hypothesis has been applied to the diffusion measurements and the micrometeorological data gathered in Project Prairie Grass in order to determine the Lagrangian correlation coefficient for lateral motion for timelags corresponding to downwind travel of from 50m. to 800 m. In determining this coefficient it is necessary to compute the second derivative with respect to time of the variance of the lateral distribution of mean concentration at points downwind from a continuous point source. An objective technique for computing this derivative is described. A preliminary analysis of thirteen experiments indicates that, for timelags between about five and sixty seconds, the Lagrangian correlation coefficient EL may exceed the Eulerian correlation coefficient RE in some experiments, be equal to it in others, and be less than it in still others. There is a tendency for RL - RE to decrease as the mean wind speed decreases and as the stability ratio increases.

A diffusion-deposition model is developed for use in estimating dosage levels due to inflight release of fission fragments from a nuclear-powered aircraft. The model is based on the work of Sutton for diffusion and the work of Chamberlain for deposition. The model considers an elevated instantaneous point source and an elevated instantaneous line source oriented at an arbitrary angle to the mean wind direction. Suggested values of the various deposition, rain-out and diffusion parameters to be used with the model are presented along with a qualitative discussion of the uncertainties of the model and the suggested parameters.