Title Depositional ice nucleation on solid ammonium sulfate and glutaric acid particles
Author Baustian, K.J.; Wise, M.E.; Tolbert, M.A.
Author Affil Baustian, K.J., University of Colorado, Cooperative Institute for Research in Environmental Sciences, Boulder, CO
Source Atmospheric Chemistry and Physics, 10(5), p.2307-2317, . Publisher: Copernicus, Katlenburg-Lindau, International. ISSN: 1680- 7316
Publication Date 2010
Notes In English. Published in Atmospheric Chemistry and Physics Discussions: 5 October 2009, http://www.atmos-chem-phys- discuss.net/9/20063/2009/acpd-9-20063- 2009.html ; accessed in May, 2011. 47 refs. GeoRef Acc. No: 310090
Index Terms clouds (meteorology); polar stratospheric clouds; crystals; experimentation; ice; ice crystals; nucleation; optical properties; ozone; particles; polar regions; solid phases; spectra; stratosphere; temperature; water vapor; polar regions; ammonium sulfate; chemical ratios; clouds; experimental studies; glutaric acid; heterogeneity; laboratory studies; Raman spectra; saturation; SEM data; solid phase; sulfates; tropopause; troposphere
Abstract Heterogeneous ice nucleation on solid ammonium sulfate and glutaric acid particles was studied using optical microscopy and Raman spectroscopy. Optical microscopy was used to detect selective nucleation events as water vapor was slowly introduced into an environmental sample cell. Particles that nucleated ice were dried via sublimation and examined in detail using Raman spectroscopy. Depositional ice nucleation is highly selective and occurred preferentially on just a few ammonium sulfate and glutaric acid particles in each sample. For freezing temperatures between 214 K and 235 K an average ice saturation ratio of S=1.100.07 for solid ammonium sulfate was observed. Over the same temperature range, S values observed for ice nucleation on glutaric acid particles increased from 1.2 at 235 K to 1.6 at 218 K. Experiments with externally mixed particles further show that ammonium sulfate is a more potent ice nucleus than glutaric acid. Our results suggest that heterogeneous nucleation on ammonium sulfate may be an important pathway for atmospheric ice nucleation and cirrus cloud formation when solid ammonium sulfate aerosol particles are available for ice formation. This pathway for ice formation may be particularly significant near the tropical tropopause region where sulfates are abundant and other species known to be good ice nuclei are depleted.
URL http://www.atmos-chem-phys.net/10/2307/2010/acp-10-2307-2010.pdf
Publication Type journal article
Record ID 65006763