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pure and applied geophysics

, Volume 157, Issue 9, pp 1557–1569 | Cite as

Characteristics of Cloud Drop Spectra at Different Levels and with Respect to Cloud Thickness

  • S. K. Paul

Abstract

—Measurements on drop size spectra were made in cumulus clouds over Pune (inland) region on many days during the summer monsoon seasons. In this paper, the measurements in non-raining cumulus clouds made in the years 1984, 1985 and 1986 at different levels and for different cloud thickness have been studied. In general, the drop size spectra broadened with height and the concentration of drops with diameter > 50 μm (N L ), mean volume diameter (MVD), liquid water content (LWC) and dispersion increased with height while the concentration of drops with diameter < 20 μm (N S ) and the total concentration of drops (N T ) decreased with height. The average drop size distributions were unimodal at the lower levels while they were bimodal at the higher levels. High water contents were confined to drops in the size range 5–25 μm at both higher and lower levels. The average drop size spectra were broader and N L , LWC, MVD and dispersion greater while N T and N S smaller for thicker clouds (range of vertical extent 1.1–2.1 km) as compared to those for thinner clouds (range of vertical extent 0.3–1.1 km). Water contents for the drops > 28 μm were higher while those for the drops > 28 μm lower in thicker clouds than in thinner clouds. The average drop size distributions were bimodal in the former case, while they were unimodal in the other case.

Key Words: Cloud drop size spectrum, higher and lower levels, cloud thickness, liquid water content, drop concentrations, mean volume diameter, dispersion, unimodal, bimodal. 

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Copyright information

© Birkhäuser Verlag Basel, 2000

Authors and Affiliations

  • S. K. Paul
    • 1
  1. 1.Indian Institute of Tropical Meteorology, Pune 411 008, India. Fax: (0212) 34 78 25.IN

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