Microphysical simulations of new particle formation in the upper troposphere and lower stratosphere
Open Access
- 9 September 2011
- journal article
- research article
- Published by Copernicus GmbH in Atmospheric Chemistry and Physics
- Vol. 11 (17), 9303-9322
- https://doi.org/10.5194/acp-11-9303-2011
Abstract
Using a three-dimensional general circulation model with sulfur chemistry and sectional aerosol microphysics (WACCM/CARMA), we studied aerosol formation and microphysics in the upper troposphere and lower stratosphere (UTLS) as well as the middle and upper stratosphere based on three nucleation schemes (two binary homogeneous schemes and an ion-mediated scheme related to one of the binary schemes). Simulations suggest that ion-mediated nucleation rates in the UTLS are 25 % higher than its related binary scheme, but that the rates predicted by the two binary schemes vary by two orders of magnitude. None of the nucleation schemes is superior at matching the limited observations available at the smallest sizes. However, it is found that coagulation, not nucleation, controls number concentration at sizes greater than approximately 10 nm. Therefore, based on this study, processes relevant to atmospheric chemistry and radiative forcing in the UTLS are not sensitive to the choice of nucleation schemes. The dominance of coagulation over other microphysical processes in the UTLS is consistent with other recent work using microphysical models. Simulations using all three nucleation schemes compare reasonably well to observations of size distributions, number concentration across latitude, and vertical profiles of particle mixing ratio in the UTLS. Interestingly, we find that we need to include Van der Waals forces in our coagulation scheme to match the UTLS aerosol concentrations. We conclude that this model can reasonably represent sulfate microphysical processes in the UTLS, and that the properties of particles at atmospherically relevant sizes appear to be insensitive to the details of the nucleation scheme. We also suggest that micrometeorites, which are not included in this model, dominate the aerosol properties in the upper stratosphere above about 30 km.Keywords
This publication has 90 references indexed in Scilit:
- Can cosmic rays affect cloud condensation nuclei by altering new particle formation rates?Geophysical Research Letters, 2009
- Massive global ozone loss predicted following regional nuclear conflictProceedings of the National Academy of Sciences, 2008
- Thirty years of in situ stratospheric aerosol size distribution measurements from Laramie, Wyoming (41°N), using balloon‐borne instrumentsJournal of Geophysical Research: Solid Earth, 2003
- Factors controlling tropospheric O3, OH, NOx and SO2 over the tropical Pacific during PEM‐Tropics BJournal of Geophysical Research: Solid Earth, 2001
- Measurement of aerosol sulfuric acid: 2. Pronounced layering in the free troposphere during the second Aerosol Characterization Experiment (ACE 2)Journal of Geophysical Research: Solid Earth, 2001
- Sulfur dioxide distribution over the Pacific Ocean 1991–1996Journal of Geophysical Research: Solid Earth, 1999
- UV absorption cross sections for SO3Geophysical Research Letters, 1997
- A new parameterization of H2SO4/H2O aerosol composition: Atmospheric implicationsGeophysical Research Letters, 1997
- On the formation and persistence of subvisible cirrus clouds near the tropical tropopauseJournal of Geophysical Research: Solid Earth, 1996
- The Thermodynamic Properties of Aqueous Sulfuric Acid Solutions and Hydrates from 15 to 300°K.1Journal of the American Chemical Society, 1960