Abstract
The raindrop size, the raindrop shape, and the raindrop fall velocity measured are shown. It was found that many small raindrops of 50 to 500 μm diameter whose sizes have never been measured, exist in common rainfall. Also the distribution of canting angle of deformed raindrops is measured. For estimating the microwave attenuation due to rainfall, especially that of millimeter waves, a probability distribution function of raindrop size is presented. Finally, it is shown that the raindrop size distribution is not uniquely determined only by rainfall intensity.
Analyse
L’auteur présente des mesures de dimensions et de vitesses de chute des gouttes d’eau, ainsi que l’étude de leur forme. Des petites gouttes de 50 à 500 μm de diamètre dont les dimensions n’ont encore jamais été mesurées, existent dans des pluies ordinaires. Il mesure également la distribution de l’angle d’inclinaison des gouttes déformées. Pour estimer l’atténuation des hyperfréquences due aux précipitations, en particulier pour les longueurs d’onde millimétriques, il présente une fonction de distribution des diamètres des gouttes. La distribution de ces diamètres n’est pas uniquement fonction de l’intensité des précipitations.
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Ugai, S., Kato, K., Nishijima, M. et al. Fine structure of rainfall. Ann. Télécommunic. 32, 422–429 (1977). https://doi.org/10.1007/BF03003489
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DOI: https://doi.org/10.1007/BF03003489