Title Heterogeneous nucleation of ice on anthropogenic organic particles collected in Mexico City
Author Knopf, D.A.; Wang, B.; Laskin, A.; Moffet, R.C.; Gilles, M.K.
Author Affil Knopf, D.A., State University of New York at Stony Brook, Institute for Terrestrial and Planetary Atmospheres, Stony Brook,NY. Other: Pacific Northwest National Laboratory; Lawrence Berkeley National Laboratory
Source Geophysical Research Letters, 37(11), Citation L11803. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0094-8276
Publication Date 2010
Notes In English. 31 refs. GeoRef Acc. No: 309537
Index Terms aerosols; clouds (meteorology); crystals; human activity; ice; ice crystals; pollution; Mexico--Mexico City; atmosphere; cirrus clouds; clouds; Federal District Mexico; heterogeneity; Mexico; Mexico City Mexico; Mexico state; organic compounds
Abstract This study reports on heterogeneous ice nucleation activity of predominantly organic (or coated with organic material) anthropogenic particles sampled within and around the polluted environment of Mexico City. The onset of heterogeneous ice nucleation was observed as a function of particle temperature (Tp), relative humidity (RH), nucleation mode, and particle chemical composition which is influenced by photochemical atmospheric aging. Particle analyses included computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). In contrast to most laboratory studies employing proxies of organic aerosol, we show that anthropogenic organic particles collected in Mexico City can potentially induce ice nucleation at experimental conditions relevant to cirrus formation. The results suggest a new precedent for the potential impact of organic particles on ice cloud formation and climate.
URL http://hdl.handle.net/10.1029/2010GL043362
Publication Type journal article
Record ID 65006570