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  • Author or Editor: J. A. Businger x
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J. A. Businger

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J. A. Businger

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J. A. Businger

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By reviewing the physics of the processes leading to dry deposition in the atmospheric surface layer, a number of corrections and possible errors in the determination of the dry deposition fluxes are identified. The concept of deposition velocity is examined, its usefulness discussed, and some pitfalls are pointed out. An overview is given of the various micrometeorological methods with which dry deposition can be determined and some of their limitations are indicated. With this background a number of recent publications on dry deposition have been analyzed. It is apparent that in most cases a more complete documentation is needed of the structure of the surface layer and the adjacent planetary boundary layer. Errors related to advection and entrainment are especially difficult or impossible to assess because of inadequate information about the surroundings and the height of the boundary layer.

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J. C. Kaimal and J. A. Businger

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The paper describes the characteristics of a convective plume and a dust devil from measurements made at 5.66 and 22.6 m above a flat uniform site in Kansas. The velocity fluctuations were measured with a continuous-wave, three-component sonic anemometer and the temperature fluctuations with a fine platinum wire thermometer. The data show that the plume is basically a non-rotating system; it is more tilted in the downwind direction than the dust devil, travels at a lower velocity than the mean wind speed at 0.5 m, and requires vertical stretching for its maintenance in the presence of wind shear. The dust devil shows a down-draft in the middle, travels at a higher velocity than the mean wind at 32 m, and derives much of its stability from rotation. Both systems tend to transport momentum upward, against the velocity gradient, which probably accounts for the very low and sometimes negative stresses observed during unstable conditions.

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J. C. Kaimal and J. A. Businger

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J. C. Kaimal and J. A. Businger

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A sonic anemometer-thermometer, based on transmission of continuous sound waves and determination of phase angle variations, has been developed. The instrument is designed to measure the fluctuations in the vertical wind component and temperature simultaneously. Measurement of these two quantities enables one to determine the eddy heat flux in the turbulent boundary layer. Field tests indicate that the instrument performs satisfactorily.

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J. C. Kaimal and J. A. Businger

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S. E. Larsen, F. W. Weller, and J. A. Businger

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A continuous wave sonic anemometer-thermometer has been developed for simultaneous measurements of vertical velocity and temperature. The phase angle fluctuations are detected by means of a monolithic integrated phase-locked loop, the latter feature providing for inexpensive and accurate electronics. The principle is described and discussed.

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J. A. Businger, M. Miyake, A. J. Dyer, and E. F. Bradley

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The results of a heat flux comparison experiment carried out at Hay, New South Wales, Australia, during May 1966 using a sonic anemometer thermometer (SAT), Fluxatron and Evapotron are reported. The instruments agree with each other to within a factor of 2 for individual runs. The large fluctuations from run to run of the individual estimates are mainly caused by the fact that the Eulerian point average does not provide an adequate statistical sample of the heat flux. This point is illustrated by the non-stationary behavior of the instantaneous product of vertical wind and temperature. As auxiliary results, values of σ w/u * and σ T/T * have been obtained which are somewhat higher than, but in general agreement with, observations reported by Mordukhovich and Zwang.

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