Meteorological and aerosol effects on marine cloud microphysical properties

Autor(en)

K. J. Sanchez, L. M. Russell, R. L. Modini, A. A. Frossard, L. Ahlm, C. E. Corrigan, G. C. Roberts, L. N. Hawkins, J. C. Schroder, A. K. Bertram, R. Zhao, A. K. Y. Lee, J. J. Lin, A. Nenes, Z. Wang, Anna Wonaschütz, A. Sorooshian, K. J. Noone, H. Jonsson, D. Toom, A. M. Macdonald, W. R. Leaitch, J. H. Seinfeld

Abstrakt

Meteorology and microphysics affect cloud formation, cloud droplet distributions, and shortwave reflectance. The Eastern Pacific Emitted Aerosol Cloud Experiment and the Stratocumulus Observations of Los-Angeles Emissions Derived Aerosol-Droplets studies provided measurements in six case studies of cloud thermodynamic properties, initial particle number distribution and composition, and cloud drop distribution. In this study, we use simulations from a chemical and microphysical aerosol-cloud parcel (ACP) model with explicit kinetic drop activation to reproduce observed cloud droplet distributions of the case studies. Four cases had subadiabatic lapse rates, resulting in fewer activated droplets, lower liquid water content, and higher cloud base height than an adiabatic lapse rate. A weighted ensemble of simulations that reflect measured variation in updraft velocity and cloud base height was used to reproduce observed droplet distributions. Simulations show that organic hygroscopicity in internally mixed cases causes small effects on cloud reflectivity (CR) (<0.01), except for cargo ship and smoke plumes, which increased CR by 0.02 and 0.07, respectively, owing to their high organic mass fraction. Organic hygroscopicity had larger effects on droplet concentrations for cases with higher aerosol concentrations near the critical diameter (namely, polluted cases with a modal peak near 0.1 mu m). Differences in simulated droplet spectral widths (k) caused larger differences in CR than organic hygroscopicity in cases with organic mass fractions of 60% or less for the cases shown. Finally, simulations from a numerical parameterization of cloud droplet activation suitable for general circulation models compared well with the ACP model, except under high organic mass fraction.

Organisation(en)

Aerosolphysik und Umweltphysik

Externe Organisation(en)

University of California, San Diego, École polytechnique fédérale de Lausanne, University of California, Berkeley, Centre National De La Recherche Scientifique (CNRS), Harvey Mudd College, University of British Columbia (UBC), University of Colorado, Boulder, University of Toronto, University of Arizona, Stockholm University, Center for Interdisciplinary Remotely Piloted Aircraft Studies, Environment and Climate Change Canada, California Institute of Technology (Caltech), Georgia Institute of Technology

Journal

Journal of Geophysical Research: Atmospheres

Band

121

Seiten

4142-4161

Anzahl der Seiten

20

ISSN

2169-897X

DOI

https://doi.org/10.1002/2015JD024595

Publikationsdatum

04-2016

Peer-reviewed

Ja

ÖFOS 2012

103039 Aerosolphysik

Schlagwörter

ASJC Scopus Sachgebiete

Forestry, Aquatic Science, Soil Science, Water Science and Technology, Earth-Surface Processes, Geochemistry and Petrology, Geophysics, Oceanography, Palaeontology, Ecology, Space and Planetary Science, Earth and Planetary Sciences (miscellaneous), Atmospheric Science

Sustainable Development Goals

SDG 13 – Maßnahmen zum Klimaschutz

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/624a97b5-289c-4290-a2b2-066cff6ca944