A035-0005
Tara Pacific Expedition: global sampling of marine aerosols and surface ocean
Tuesday, 8 December 2020
Poster
Guillaume Bourdin1, J. Michel Flores2, Rachel Lauren Kelly3, Natalie Cohen4, Emmanuel Boss1, Fabien Lombard5, G Gorsky6, Prof Seth John7, Assaf Vardi8 and Ilan Koren2, (1)University of Maine, Orono, ME, United States, (2)Weizmann Institute of Science, Earth and Planetary Sciences, Rehovot, Israel, (3)University of Southern California, Earth Sciences, Los Angeles, CA, United States, (4)Woods Hole Oceanographic Institution, Falmouth, MA, United States, (5)Laboratoire d'Océanographie de Villefranche (LOV), UMR 7093, Sorbonne Université, Villefranche-sur-Mer, France, (6)CNRS, Laboratoire d'Océanographie de Villefranche-sur-Mer, Villefranche-sur-Mer, France, (7)University of Southern California, Department of Earth Sciences, Los Angeles, CA, United States, (8)Weizmann Institute of Science, Plant and Environmental Science, Rehovot, Israel
Abstract:
Some of the most significant processes affecting Earth's climate occur at the ocean surface interface, where fluxes of energy, momentum, gases, and particles between ocean and the atmosphere take place. These processes pose some of the main challenges in climate and oceanographic research. The contribution of marine originating aerosol to cloud formation and total atmosphere radiative balance still shows large uncertainty. Moreover, marine aerosols, including mineral dust are a source of essential trace metals for phytoplankton growth in some of the most remote and oligotrophic parts of the ocean. Secondary aerosols can also be produced from the oxidation of dimethylsulphides, themselves produced by phytoplankton.
The Tara Pacific expedition, launched in May 2016 aboard the schooner Tara, was a 29-month exploration over 110,000 km across the Atlantic and Pacific oceans where inter-island and open ocean surface plankton and neuston community structures, together with key atmospheric properties, were measured to study links between the two boundary layer properties. We simultaneously measured sea surface physical, chemical and bio-optical properties as well as marine aerosols at 30 m above the sea surface.
Here we present the spatial and temporal variability of the physical properties of aquatic aerosols across Tara’s route. We explore the differences between aquatic aerosols emitted in the oligotrophic parts of the ocean with the biological active areas but also between the Atlantic and Pacific Oceans. We examine the main co-occurrences of specific marine aerosols and ocean surface properties associated with trace metal and chlorophyll concentrations. The Atlantic Ocean had higher aerosol concentration originating from sedimentation from the free troposphere whereas Pacific Ocean had lower concentration mainly produced by oceanic processes. Overall, higher aerosol concentrations were correlated with higher trace metal and chlorophyll concentration in the surface ocean.
