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Title:	Microspherules in snow and ice-fog crystals
Authors:	Kumai, Motoi.
Keywords:	Snow Ice Snow crystals Ice crystals Microspherules Ice fog Electron microscope Electron microscopy Electron diffraction Particle analysis Impurities Condensation nuclei
Publisher:	Cold Regions Research and Engineering Laboratory (U.S.) Engineer Research and Development Center (U.S.)
Series/Report no.:	Research report (Cold Regions Research and Engineering Laboratory (U.S.)) ; 245.
Description:	Research Report Abstract: Spherules found in snow crystals, ice-fog crystals, fallout particles, and fly ash were studied with an electron microscope using the electron diffraction method. The central part of the residues of 1004 specimens of natural snow crystals from Greenland, the United States, and Japan were examined; 14 spherules 0.1 to 1.5μ in radius were found among them. The residues of 658 artificial ice-fog crystals formed from water vapor in flue gases of coal-burning electric power plants at Fairbanks, Alaska, were also examined; nine spherules were found. Spherules similar to those found in ice-fog residues were found in furnace-produced fly ash fallout at Fairbanks, Alaska. Electron and optical microscope examination of spherules found in Greenland snow reveals a size distribution of the form 𝖽𝖭/𝖽(𝗅𝗈𝗀 𝗋) = 𝖢𝗋^-β where β ≈ 3. The properties of spherules and the mean mass of snow crystals from Greenland are described. The electron microscope study indicated that less than 0.7% of the 1004 snow crystals contained spherules of possible extraterrestrial origin, and that snow crystals are formed mainly on clay mineral particles by heterogeneous nucleation.
Rights:	Approved for public release; distribution is unlimited.
URI:	http://hdl.handle.net/11681/5919
Appears in Collections:	Research Report