Ion-mediated nucleation as an important global source of tropospheric aerosols

• Main Authors: Yu, F., Wang, Z., Luo, G., Turco, R.
• Other Authors: Atmospheric Sciences Research Center (ASRC), University at Albany SUNY, State University of New York (SUNY)-State University of New York (SUNY), Institute of Atmospheric Physics Beijing (IAP), Chinese Academy of Sciences Beijing (CAS), Department of Atmospheric and Oceanic Sciences Los Angeles (AOS), University of California Los Angeles (UCLA), University of California (UC)-University of California (UC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2008
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Antarc*; Antarctica
• Online Access: https://hal.archives-ouvertes.fr/hal-00296546; https://hal.archives-ouvertes.fr/hal-00296546/document; https://hal.archives-ouvertes.fr/hal-00296546/file/acp-8-2537-2008.pdf

International audience Aerosol nucleation events have been observed at a variety of locations worldwide, and may have significant climatic and health implications. While ions have long been suggested as favorable nucleation embryos, their significance as a global source of particles has remained uncertain. Here, an ion-mediated nucleation (IMN) mechanism, which incorporates new thermodynamic data and physical algorithms, has been integrated into a global chemical transport model (GEOS-Chem) to study ion-mediated particle formation in the global troposphere. The simulated annual mean results have been compared to a comprehensive set of data relevant to particle nucleation around the globe. We show that predicted annual spatial patterns of particle formation agree reasonably well with land-, ship-, and aircraft-based observations. Our simulations show that, globally, IMN in the boundary layer is largely confined to two broad latitude belts: one in the northern hemisphere (~20° N?70° N), and one in the southern hemisphere (~30° S?90° S). In the middle latitude boundary layer over continents, the annual mean IMN rates are generally above 10 4 cm ?3 day ?1 , with some hot spots reaching 10 5 cm ?3 day ?1 . The zonally-averaged vertical distribution of IMN rates indicates that IMN is significant in the tropical upper troposphere, the entire middle latitude troposphere, and over Antarctica. Comparing the relative strengths of particle sources due to IMN and due to primary particle emissions demonstrates that IMN is significant on a global scale. Further research is needed to reduce modeling uncertainties and to understand the ultimate contribution of freshly nucleated particles to the abundance of cloud condensation nuclei.