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Interactions between aerosols and rain clouds as a function of aerosol type and source- Preliminary results. Presented by: Assaf Zipori Advised by: Profs. Daniel Rosenfeld & Yigal Erel. Aerosol-cloud interactions.
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Interactions between aerosols and rain clouds as a function of aerosol type and source- Preliminary results Presented by:AssafZipori Advised by: Profs. Daniel Rosenfeld & YigalErel
Aerosol-cloud interactions • Different aerosols interact differently with cloud droplets and thus influence cloud composition and precipitation forming processes. • The main parameters that determine the type of interaction are the aerosol’s size and chemical composition. • There is a relationship between aerosol size and its chemical composition. • Cloud composition plays a key role in the earth radiation budget (global scale) and in precipitation forming processes (micro scale).
Study area Central Sierra snow lab, Donner pass road, California (2100 mASL).
Methods - Sampling Snow samples (Central Sierra snow lab) Cloud samples (Mt. Lincilen -2530 mASL) Snow density measurement Snowflakes micro photography (Nikon D5100, 105mm f/2.8 macro lens)
Methods • Metal concentration analysis with ICP-MS (Agilent 7500cx) • Isotopic ratios of Sr and Pb with high resolution multi collector ICPMS (NEPTUNE Plus HR-MC-ICP-MS) • Riming rate determination from the photos 2 3 4 1 5 Clear shape of crystals with significant amount of riming rate Pristine snowflake with no riming The clear shape of snowflkes crystals demolished. Crystal shape are not seen, with spherical particles Graupel
Results- Riming rate verification Similar behavior between the estimation of snow riming rate to snow density measurement.
Aerosol sources- Pbisotpic ratio F Asia: The fraction of lead transported from Asia to western USA from the total lead concentration. It was calculated based on Ewing et al (2010). Ewing et al (2010).
F Asia verification Back trajectory time: 120 hr Time interval between trajectories: 6 hr
The influence of aerosols source on riming rate As F Asia increase, Riming rate decrees? As F Asia increase, Srisotopc ratio increase and become more marine.
Conclusions • Different aerosol sources can influence cloud properties and composition. • Carbonate aerosols enhance ice formation in clouds (relative to Al-silicates and marine aerosols) • Polluted aerosols are less effective IN. • Long range transport contributes a significant amount of aerosols, even during rain events in the western USA. • As F Asia increases, Sr source becomes more marine. • Long rang transport of aerosols from Asia to California enhance ice formation in clouds. In order to establish it, more samples are needed to be collected.