Blanc SIMI 5-6 - Blanc - SIMI 5-6 - Environnement, Terre et Espace

Sources of Marine Aerosols in the mediterranean atmosphere – SAM

Source d’aérosols marins dans l’atmosphère méditerranéenne

This project will provide quantitative and qualitative understanding of the fine marine aerosol production and characterisation in the western Mediterranean region, based on experiments on real sea waters samples performed in controlled and semi-controlled environments (laboratory and mesocosms).

Objectives

The project will answer to the following fundamental questions:<br />I. is there any contribution of organic matter to the primary marine aerosol produced from a region of the Mediterranean sea surface waters, if yes, is it seasonal dependant, and space dependant?<br />II. is the organic fraction measured in the primary aerosol produced by bubble bursting of biological origin, as in the Atlantic Ocean, or it is correlated to other components as the anthropogenic inputs?<br />III. how the photochemical aging affect these particles?<br />IV. can the photo-oxidative processes occurring at the air-sea water of interface produce some SOA?<br />V. organic matter is both water soluble (WSOM) and water insoluble (WIOM) – different sources?<br />SAM will provide qualitative and quantitative information on:<br />• Chemical and biological characterization of the sea-water surface layers in some regions of the Western Mediterranean sea (seasonal variation);<br />• primary organic aerosol (POA) and its photo-oxidative aging (OPOA) generated by bubble bursting technique of sea water samples (laboratory investigation);<br />• secondary organic aerosol (SOA) produced by photochemical aging of sea-water surface samples (laboratory investigation); <br />• POA and its photo-oxidative aging (OPOA) produced during a mesocoms experiments (field studies);<br />• SOA produced during a mesocoms experiment (field studies); <br />• Identification of possible bias from laboratory study and inputs on the strategy to adopt in the future for a better caracterisation of marine aerosol in Mediterranean regions;<br />• Emission fluxes of marine aerosol (POA and SOA);<br /><br />

Experimental approach:
Task 1: Tache 1. Sampling and Water samples chemical and physical analysis (DOM, CDOM characterization, Chlorophyll-a, Carbohydrates, dicarboxylic acids, Bacterioplankton, Picoplankton Nanoplankton, Specific lipid abiotic degradation markers). In-situ UV irradiance of the sea water column between 0 and -20m. Identification of dissolved photo-degradation products UV/PAR. Abiotic degradation products of sea water.

Task 2 and 3 (laboratory and mesocoms):construction of the reaction chamber (almost finished in July 2012) and bubble-bursting apparatus (water jet system) ; . Physical properties of aerosol particles: size distribution (n-SMPS and ELPI), volatility and hygroscopicity (VHTDMA), CCN, nucleation clusters NAIS and PSM; Analysis and data treatment of on-line instrumentation chemical characterization of POA, OPOA and SOA marine aerosol using an HR-TOF- AMS and a C-TOF-AMS.
Particles off-line analaysis: APCI/MS/MS, IC. Analysis of the gas-phase during OPOA and SOA experiments: PTR-ToF-MS measurement data treatment and analysis, cartridges and GC-MS sampling and analysis , other gas detectors (ozone, NOx and SO2).

The first laboratory campaign will take place in November 2012.

We will wait for the first results from the first labratory campaign.

None

The Mediterranean Sea represents a special marine environment with unique features. It is first a semi-closed Sea, characterized by elevated anthropogenic pressure (urban effluents, rivers input, oil spill, etc.), it has a relatively poor biological activity with its own specificities, and it is exposed to quite high solar radiation during a large part of the year. Our ability to understand sources and processes occurring to the marine aerosols in this region is still limited, in particular with regards to the organic fraction. This project will provide quantitative and qualitative understanding of the fine marine aerosol production and characterisation in the western Mediterranean region, based on experiments on real sea waters samples performed in controlled and semi-controlled environments (laboratory and mesocosms). The main focus of SAM is to provide estimations of the marine aerosol physical and chemical properties, as a function of the sea water composition and photochemical conditions. The effect of sea water pollutant contamination on the produced marine aerosol properties will also be investigated. The project will take advantage of a variety of state-of-the-art on-line and off-line instrumentation to characterize on one hand the primary fraction of the organic aerosol (POA) and its photochemical aging (oxidized primary organic Aerosol OPOA) and on the other hand the secondary fraction of the organic aerosol (SOA). POA will be produced by bubble bursting technique and the sea-surface layers will be exposed to environmental oxidants and light to investigate the physical and chemical properties of the newly formed SOA.
This study will deliver new fundamental knowledge about marine aerosol fluxes (POA, SOA), their chemical components and physical-chemical properties of primary emitted marine aerosol of Mediterranean Sea waters. Ultimately, source functions will be derived to feed meso-scale models with parameterizations adapted to the area.

Project coordination

Barbara D'Anna (CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE - DELEGATION REGIONALE RHONE-AUVERGNE) – barbara.danna@ircelyon.univ-lyon1.fr

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

CNRS-LMGEM UNIVERSITE AIX-MARSEILLE
LCP-IRA UNIVERSITE AIX-MARSEILLE
CNRS-IRCELYON CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE - DELEGATION REGIONALE RHONE-AUVERGNE
CNRS-LAMP CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE - DELEGATION REGIONALE RHONE-AUVERGNE

Help of the ANR 570,509 euros
Beginning and duration of the scientific project: December 2011 - 36 Months

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