10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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The Importance of Biogenic Material to the Ice Nucleating Particle Concentration in a Coastal Tropical Site
LUIS ANTONIO LADINO, Graciela Raga, Harry Alvarez-Ospina, Manuel Andino, Irma Rosas, Leticia Martinez, Eva Salinas, Javier Miranda, Zyanya Ramirez, Bernardo Figueroa, Erika Quintana, Luis Maldonado, Agustin Garcia, Cédric Chou, Victoria Irish, Allan Bertram, Universidad Nacional Autónoma de México, Mexico City, Mexico
Abstract Number: 964 Working Group: Unraveling the Many Facets of Ice Nucleating Particles and Their Interactions with Clouds
Abstract Recent studies have demonstrated that oceans can emit aerosol particles with the capability to nucleate ice in clouds known as ice nucleating particles, INPs (e.g., Wilson and Ladino et al., 2015; DeMott et al., 2016; Ladino et al., 2016; and McCluskey, et al., 2017). This is very relevant information that can be included in climate and weather models to predict the formation of ice in clouds given that most of them do not consider the oceans as a source of INPs. There is a need to conduct field measurements in tropical latitudes, since most of the past and recent studies have been conducted in mid- and high latitudes, to understand the role that marine aerosol play in the hydrological cycle and climate of tropical regions.
The present study shows the results obtained in a field campaign conducted in the village of Sisal, located on the coast of the Yucatan peninsula in Mexico (21°09ʹ55ʺN 90°01ʹ50ʺO) in January 2017, the first measurements obtained at this tropical site and one of the few data sets at similar latitudes. Aerosol particles around Sisal were found to be very efficient INPs, with onset freezing temperatures as high as -3°C (in some cases), similar to the onsets of Pseudomonas Syringae (Wex et al. 2015) or Arctic sea surface microlayer waters (Wilson et al., 2015).
The results show that the INPs concentration in Sisal is higher than in other studied locations using the same INP counter type. Surprisingly, the air masses arriving in Sisal after the passage of cold fronts reported higher INP concentrations than the average value for the whole sampling period, despite the low total aerosol concentration.
Given the large concentration of INPs at -15°C, it can be inferred that biological particles are very important in ice cloud formation in this tropical location. A variety of microorganism were identified by Gram staining analysis and by detailed bacterial strain isolation. Although the majority are of terrestrial origin, some of them are clearly oceanic, indicating that marine aerosol particles could also play a big role in cloud formation, especially in the presence of cold fronts.
References [1] DeMott, P.J., et al. (2016) Sea spray aerosol as a unique source of ice nucleating particles. Proc. Natl. Acad. Sci., 113(21), 5797-5803. [2] Ladino, L.A., et al. (2016) Addressing the ice nucleating abilities of marine aerosol: A combination of deposition mode laboratory and field measurements. Atmos. Environ., 132, 1-10. [3] McCluskey, C.S., et al. (2017) A Dynamic Link between Ice Nucleating Particles Released in Nascent Sea Spray Aerosol and Oceanic Biological Activity during Two Mesocosm Experiments. J. Atmos. Sci., 74(1), 151-166. [4] Wex, H., et al. (2015) Intercomparing different devices for the investigation of ice nucleating particles using Snomax® as test substance, Atmos. Chem. Phys., 15, 1463–1485, 2015. [5] Wilson, T.W. et al. (2015) A marine biogenic source of atmospheric ice-nucleating particles. Nature, 525(7568), 234-238.