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Deep convective clouds with sustained supercooled liquid water down to -37.5 °C

Naturevolume 405pages440442 (2000) | Download Citation



In cirrus1 and orographic wave clouds2, highly supercooled water has been observed in small quantities (less than 0.15 g m-3). This high degree of supercooling was attributed to the small droplet size and the lack of ice nuclei at the heights of these clouds1,2. For deep convective clouds, which have much larger droplets near their tops and which take in aerosols from near the ground, no such measurements have hitherto been reported. However, satellite data suggest that highly supercooled water (down to -38 °C) frequently occurs in vigorous continental convective storms3. Here we report in situ measurements in deep convective clouds from an aircraft, showing that most of the condensed water remains liquid down to -37.5 °C. The droplets reach a median volume diameter of 17 µm and amount to 1.8 g m-3, one order of magnitude more than previously reported2. At slightly colder temperatures only ice was found, suggesting homogeneous freezing. Because of the poor knowledge of mixed-phase cloud processes4, the simulation of clouds using numerical models is difficult at present. Our observations will help to understand these cloud processes, such as rainfall, hail, and cloud electrification, together with their implications for the climate system.

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  1. 1

    Sassen, K. Highly supercooled cirrus cloud water: confirmation and climatic implications. Science 227, 411–413 (1985).

  2. 2

    Heymsfield, J. A. & Miloshevich, L. M. Homogeneous ice nucleation and supercooled liquid water in orographic wave clouds. J. Atmos. Sci. 50, 2335–2353 (1993).

  3. 3

    Rosenfeld, D. & Lensky, I. M. Spaceborne sensed insights into precipitation formation processes in continental and maritime clouds. Bull. Am. Meteorol. Soc. 79, 2457–2476 (1998).

  4. 4

    Pruppacher, H. R. & Klett, J. D. Microphysics of Clouds and Precipitation 2nd edn (Kluwer Academic, Norwell, Massachusetts, 1997).

  5. 5

    Jeffery, C. A. & Austin, P. H. Homogeneous nucleation of supercooled water: results from a new equation of state. J. Geophys. Res. 102, 25269–25279 (1997).

  6. 6

    Pruppacher, H. R. A new look at homogeneous ice nucleation in supercooled water drops. J. Atmos. Sci. 52, 1924–1933 (1995).

  7. 7

    Heymsfield, J. A. & Miloshevich, L. M. Evaluation of liquid water measuring instruments in cold clouds, sampled during FIRE. J. Atmos. Ocean. Technol. 6, 378–388 (1989).

  8. 8

    Sassen, K. in Nucleation and Atmospheric Aerosols (eds Fukuta, N. & Wagner, P. E.) 287–290 (Deepak, Hampton, Virginia, 1992).

  9. 9

    Houghton, H. G. Physical Meteorology (MIT Press, Cambridge, Massachusetts, 1985).

  10. 10

    Sukarnjanaset, W., Sudhikoses, P., Tantipubthong, N., Woodley, W.L. & Rosenfeld, D. Cloud water, rainwater, temperature and draft relationships in Thai supercooled convective clouds. Preprint, Conf. on Cloud Physics/14th Conf. on Planned and Inadvertent Weather Modification J24–J27 (American Meteorological Society, Boston, Massachusetts, 1998).

  11. 11

    Williams, E. R., Zhang, R. & Rydock, J. Mixed-phase microphysics and cloud electrification. J. Atmos. Sci. 48, 2195–2203 (1991).

  12. 12

    Petersen, W. A. & Rutledge, S. A. On the relationship between cloud-to-ground lightning and convective rainfall. J. Geophys. Res. D 103, 14025–14040 (1996).

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We thank P. Sweeney, of Weather Modification, Inc., for providing the WMI Lear jet at no charge; we also thank R. Tilbury and S. Gordon for piloting the aircraft through the vigorous Texas clouds, and K. Bosch for technical support.

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  1. Institute of Earth Sciences, the Hebrew University of Jerusalem, Jerusalem, 91904, Israel

    • Daniel Rosenfeld
  2. Woodley Weather Consultants, 11 White Fir Court, Littleton, 80127, Colorado, USA

    • William L. Woodley


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Correspondence to Daniel Rosenfeld.

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