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Skylab near-infrared observations of clouds indicating supercooled liquid water dropletsOrographically-induced lee-wave clouds were observed over New Mexico by a multichannel scanning radiometer on Skylab during December 1973. Channels centered at 0.83, 1.61 and 2.125 microns were used to determine the cloud optical thickness, thermodynamic phase and effective particle size. An additional channel centered at 11.4 microns was used to determine cloud-top temperature, which was corroborated through comparison with the stereographically determined cloud top altitudes and conventional temperature soundings. Analysis of the measured near-infrared reflection functions at 1.61 and 2.125 microns are most easily interpreted as indicating the presence of liquid-phase water droplets. This interpretation is not conclusive even after considerable effort to understand possible sources for misinterpretation. However, if accepted the resulting phase determination is considered anomalous due to the inferred cloud-top temperatures being in the -32 to -47 C range. Theory for the homogeneous nucleation of pure supercooled liquid water droplets predicts very short lifetimes for the liquid phase at these cold temperatures. A possible explanation for the observations is that the wave-clouds are composed of solution droplets. Impurities in the cloud droplets could decrease the homogeneous freezing rate for these droplets, permitting them to exist for a longer time in the liquid phase, at the cold temperatures found.
Document ID
19820049326
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Curran, R. J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Wu, M.-L. C.
(NASA Goddard Space Flight Center Laboratory for Atmospheric Sciences, Greenbelt, MD, United States)
Date Acquired
August 10, 2013
Publication Date
March 1, 1982
Publication Information
Publication: Journal of the Atmospheric Sciences
Volume: 39
Subject Category
Meteorology And Climatology
Accession Number
82A32861
Distribution Limits
Public
Copyright
Other

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