## Abstract

Instantaneous diffusion estimates have been obtained from observations of smoke plumes in the neutral-unstable plan-etary boundary layer over homogenous rural terrain.

Ground-level smoke releases were photographed from an aircraft at 1000-6000 feet above the experiment field over 40 min periods, Simultaneously, wind data were recorded from a horizontal array of four tower-mounted sonic anemometer/thermometers (z = 10 m) during periods over which the mean wind direction was virtually perpendicular to the span of the array.

Sufficient data were obtained to evaluate the performance of a small-scale puff diffusion model, as well as the applicability of a recently proposed statistical theory of diffusion of Gaussian puffs.

The plumes generated by the puff diffusion model showed reason able agreement with the observed smoke diffusionf and averaged values of the observed cloud spread were found to be comparable with the statistical relative diffusion theory on the ~ 1-km scale considered.

Ground-level smoke releases were photographed from an aircraft at 1000-6000 feet above the experiment field over 40 min periods, Simultaneously, wind data were recorded from a horizontal array of four tower-mounted sonic anemometer/thermometers (z = 10 m) during periods over which the mean wind direction was virtually perpendicular to the span of the array.

Sufficient data were obtained to evaluate the performance of a small-scale puff diffusion model, as well as the applicability of a recently proposed statistical theory of diffusion of Gaussian puffs.

The plumes generated by the puff diffusion model showed reason able agreement with the observed smoke diffusionf and averaged values of the observed cloud spread were found to be comparable with the statistical relative diffusion theory on the ~ 1-km scale considered.

Original language | English |
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Publisher | Danmarks Tekniske Universitet, Risø Nationallaboratoriet for Bæredygtig Energi |
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Number of pages | 61 |

ISBN (Print) | 87-550-0949-2 |

Publication status | Published - 1983 |

Series | Denmark. Forskningscenter Risoe. Risoe-R |
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Number | 479 |

ISSN | 0106-2840 |

## Keywords

- Risø-R-479
- Risø-R-479(EN)