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Bufton, J. L.

Publications and source records attributed to Bufton, J. L..

49 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

A Radiosonde Thermal Sensor Technique for Measurement of Atmospheric Turbulence

A system was developed to measure vertical profiles of microthermal turbulence in the free atmosphere. It combines thermal sensor technology with radiosonde balloon systems. The resultant data set from each thermosonde flight is a profile of the strength and distribution of microthermal fluctuations which act as tracers for turbulence. The optical strength of this turbulence is computed and used to predict optical and laser beam propagation statistics. A description of the flight payload, examples of turbulence profiles and comparison with simultaneous stellar observations are included.

Bufton, J. L.↗
NASA NTRS1973

Comparison of vertical profile turbulence structure with stellar observations.

Vertical profiles of microthermal turbulence structure have been obtained from balloon flights to altitudes near 25 km above mean sea level. Comparison of the observed turbulence structure with meteorological data and simultaneously acquired stellar scintillation data has been successful. For this comparison integrals over the observed turbulence structure were computed as required by theory. Turbulence and wind velocity data were also employed to predict successfully stellar irradiance spectra.

Bufton, J. L.↗
NASA NTRS1973

Correlation of microthermal turbulence data with meteorological soundings in the troposphere.

Recent measurements of vertical profiles of microthermal turbulence structure are reported. Data obtained by balloon-borne temperature sensors are presented in terms of the temperature structure coefficient. Free-floating balloon flights allowed this type of measurement to be extended to an altitude of 15 km above sea level. This series of flights was accompanied by vertical profiles of wind speed and temperature that permitted calculation of wind shear and gradient Richardson number profiles. The observed correlations found to exist between microthermal turbulence layers and the standard meteorological data are discussed briefly in light of the theory.

Bufton, J. L.↗
NASA NTRS1972

Fourier spectrum of beams chopped by circular apertures.

The circular apertures in the case investigated are uniformly spaced. It is assumed that modulation does not alter beam collimation and that diffraction from aperture edges can be neglected. It is also assumed that the diameter of the apertures is equal to the spacing between the trailing edge and the leading edge of successive apertures. The motion of apertures across the beam is rectilinear. Calculations have been performed for both homogeneous and bivariate normal intensity distributions. The absolute values of the first six Fourier coefficients are plotted as a function of the beam radius normalized to aperture radius.

Cohen, S. C.↗
NASA NTRS1972

Comparison of vertical profile turbulence structure with stellar observations.

Vertical profiles of microthermal turbulence structure have been obtained from balloon flights to altitudes near 25 km above mean sea level. Comparison of the observed turbulence structure with meteorological data and simultaneously acquired stellar scintillation data has been successful. For this comparison integrals over the observed turbulence structure were computed as required by theory. Turbulence and wind velocity data were also employed to successfully predict stellar irradiance spectra.

Bufton, J. L.↗
NASA NTRS1972

Measurements of turbulence profiles in the troposphere.

During a series of balloon flights in southeastern New Mexico new data was obtained on microthermal atmospheric turbulence structure from the surface to altitudes of 12 to 15 km and the beginning of the tropopause region. It was possible to compute the temperature structure coefficient and the refractive-index-structure coefficient. The major significance of the data is the thermal evidence for turbulence and the strength of this effect in the upper-altitude regions.

Bufton, J. L.↗
NASA NTRS1972

Results of the Balloon Atmospheric Propagation Experiment flights of 1970 (BAPE 1)

Two laser beams, one argon (5145 A) and one CO2 (10.6 microns), were propagated over vertical path from the ground to receivers located above the atmosphere, and the scintillation of the beams was measured. Simulataneous measurement of the state of turbulence along the path permitted the comparison of scintillation statistics with theory. The effects of atmospheric turbulence over a vertical or near-vertical path are discussed.

Minott, P. O.↗