Enhanced Residence Of Submicron Si-Rich Volcanic Particles In The Lower Stratosphere
Journal Article: Enhanced Residence Of Submicron Si-Rich Volcanic Particles In The Lower Stratosphere
AbstractAbundant submicron Si-rich grains were collected in the lower stratosphere between May 1981 and January 1982. Analytical electron microscopy shows that the morphology, surface features and chemical compositions of these platey grains are consistent with keatite. Keatite forms by devitrification of amorphous Si-rich grains that condensed in ascending volcanic eruption clouds. Low settling rates for platey grains should cause concentration of Si-rich grains in the stratosphere during extended periods of volcanic activity. Such a concentration is not observed probably because the grains were present as small aggregates with greater settling rates. Aggregation did not occur in the atmosphere because collision frequencies are too low. Thus aggregation took place in the volcanic cloud. The faster settling rates for the aggregates is still sufficiently slow to increase the amount of small volcanic particles in the stratosphere thereby enhancing the amount of sites for heterogeneous aerosol nucleation.
- Frans J. M. Rietmeijer
- Published Journal
- Journal of Volcanology and Geothermal Research, 1988
- Not Provided
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Frans J. M. Rietmeijer. 1988. Enhanced Residence Of Submicron Si-Rich Volcanic Particles In The Lower Stratosphere. Journal of Volcanology and Geothermal Research. (!) .