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| Titel |
Impact of interannual variations in sources of insoluble aerosol species on orographic precipitation over California's central Sierra Nevada |
| VerfasserIn |
J. M. Creamean, A. P. Ault, A. B. White, P. J. Neiman, F. M. Ralph, P. Minnis, K. A. Prather |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 11 ; Nr. 15, no. 11 (2015-06-15), S.6535-6548 |
| Datensatznummer |
250119814
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| Publikation (Nr.) |
 copernicus.org/acp-15-6535-2015.pdf |
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| Zusammenfassung |
| Aerosols that serve as cloud condensation nuclei (CCN) and ice nuclei (IN)
have the potential to profoundly influence precipitation processes.
Furthermore, changes in orographic precipitation have broad implications for
reservoir storage and flood risks. As part of the CalWater field campaign
(2009–2011), the variability and associated impacts of different aerosol
sources on precipitation were investigated in the California Sierra Nevada
using an aerosol time-of-flight mass spectrometer for precipitation
chemistry, S-band profiling radar for precipitation classification, remote
sensing measurements of cloud properties, and surface meteorological
measurements. The composition of insoluble residues in precipitation samples
collected at a surface site contained mostly local biomass burning and
long-range-transported dust and biological particles (2009), local sources
of biomass burning and pollution (2010), and long-range transport (2011).
Although differences in the sources of insoluble residues were observed from
year to year, the most consistent source of dust and biological residues
were associated with storms consisting of deep convective cloud systems with
significant quantities of precipitation initiated in the ice phase. Further,
biological residues were dominant (up to 40%) during storms with
relatively warm cloud temperatures (up to −15 °C), supporting the
important role bioparticles can play as ice nucleating particles. On the
other hand, lower percentages of residues from local biomass burning and
pollution were observed over the three winter seasons (on average 31 and
9%, respectively). When precipitation quantities were relatively low,
these insoluble residues most likely served as CCN, forming smaller more
numerous cloud droplets at the base of shallow cloud systems, and resulting
in less efficient riming processes. Ultimately, the goal is to use such
observations to improve the mechanistic linkages between aerosol sources and
precipitation processes to produce more accurate predictive weather forecast
models and improve water resource management. |
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