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Chantier Méditerranée – Aix-En-Provence – Nov. 2008 1/17 1. Main regional stakes - Ambient air quality - Chemistry-climate interactions - Impact on ecosystems.

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Presentation on theme: "Chantier Méditerranée – Aix-En-Provence – Nov. 2008 1/17 1. Main regional stakes - Ambient air quality - Chemistry-climate interactions - Impact on ecosystems."— Presentation transcript:

1 Chantier Méditerranée – Aix-En-Provence – Nov /17 1. Main regional stakes - Ambient air quality - Chemistry-climate interactions - Impact on ecosystems 2. Scientific objectives 3. Interfaces with other projects ChArMEx The Chemistry-Aerosol Mediterranean Experiment Contact:

2 Chantier Méditerranée – Aix-En-Provence – Nov /17 ChArMEx is the atmospheric chemistry component of the programme: it deals with short-lived tropospheric species ChArMEx

3 Chantier Méditerranée – Aix-En-Provence – Nov /17 Our motivation The remote Mediterranean atmosphere offers the best combined possibilities to follow very diverse polluted continental air masses over the basin using satellites (clear sky), background monitoring (observatories) and field campaigns (proximity) to constrain coupled chemistry-transport and chemistry-climate models ability to simulate all relevant dynamical and chemical processes In addition, the oligotrophic Mediterranean waters offers the best opportunity to couple atmospheric and marine biogeochemical models The "Chantier" offers a great opportunity for multidisciplinary coupled approaches (ChArMEx- HyMeX-MERMEX-SICMED)

4 Chantier Méditerranée – Aix-En-Provence – Nov /17 The Mediterranean marine atmosphere is heavily impacted by continental air masses Forest fires Biomass burning Volcanic sulfate Biogenic emissions Seasalts Marine biogenic emissions All types of continental and marine sources of particles and reactive gases Forest fires

5 Chantier Méditerranée – Aix-En-Provence – Nov /17 The Mediterranean: an intense summer photochemistry with a regional ozone peak Example of open questions: Relative contributions of long-distance transport and regional pollution sources (decreasing European emissions) Impact on the radiative budget Long term trends and evolution GOME JJA2000 tropospheric O 3 column (DU) Summer max.: ~+20 ppb PREVAIR 14 July 2006 O 3 peak (µg m -3 )

6 Chantier Méditerranée – Aix-En-Provence – Nov /17 The Mediterranean: the regional European maximum in aerosol 2000 annual average aerosol column mass load from AEROCOM models (courtesy of Christiane Textor, after Textor et al., ACP, 2006) Many open questions: - model components not validated (organics, deposition …) - uncertain trends - impacts not quantified… Continental sources dominate There is a strong maximum in the dry season (no wet scavenging, increased emissions…)

7 Chantier Méditerranée – Aix-En-Provence – Nov /17 Enjeu sociétal: améliorer les prévisions de qualité de lair Summer 2001 (courtesy of K. Sartelet et al.) Strong biases: major need to improve - desert dust - soot & organics (anthropogenic emissions, emissions of biogenic and semi- volatile compounds, SOA formation)

8 Chantier Méditerranée – Aix-En-Provence – Nov /17 Autre enjeu: quantifier la contribution du transport longue distance Corse Matin, 17 octobre 2008

9 Chantier Méditerranée – Aix-En-Provence – Nov /17 Simulations of the difference in radiative flux at TOA between present and pre-industrial period, considering changes in CO 2 and sulphate concentrations (Le Treut et al., J. Climate, 1998) Direct forcing of sulphates (min. -2.8, max. 0.2, mean -0.3 W m -2 ) 0 0 Radiative effects of aerosols dominate those of greenhouse gases at the regional scale CO 2 forcing (min. 0.0, max. 1.0, mean +0.5 W m -2 ) Indirect forcing of sulphates (min , max. 0.9, mean -0.8 W m -2 ) the Mediterranean is among the most affected regions

10 Chantier Méditerranée – Aix-En-Provence – Nov /17 Aged biomass burning o = 0.89): -60 W m -2 (Formenti et al. JGR, 2002) Anthropogenic aerosol ( o = 0.87): -18 W m -2 (Markowicz et al., GRL, 2002) Desert dust ( o = ): -13, -24, -37 W m -2 Non dust: -37 and -39 W m -2 (Meloni et al., JGR, 2003 and 2004) Pollution aerosol ( o = ): -66 W m -2 (Roger et al., Atmos. Env., 2006) The Mediterranean aerosols have a large impact on the solar radiation

11 Chantier Méditerranée – Aix-En-Provence – Nov /17 AOT 532 =0.6 o ~0.85 (Léon et al., JGR, 2002) Direct effect -15 to -20 W m -2 gradient <0 stratification Evaporation of low clouds (Ackerman et al., 2000) Modification of the latent heat flux (-20% over the dry season! Ramanathan et al., JGR, 2001 ) gradient >0 convection -40 to -50 W m

12 Chantier Méditerranée – Aix-En-Provence – Nov /17 ACE ACE ACE INDOEX SCAR-B1995 TARFOX1996 SCAR-C1994 SCAR-A1993 SAFARI2000 SHADE2000 AMMA PRIDE2000 ABC MINOS Polder Aerosol Index (March 1997) 0.5 Chemistry/aerosol-climate interaction studies are based on regional experiments Journées IPSL Méditerranée, Jussieu, oct EUCAARI The western Med has been neglected up to now

13 Chantier Méditerranée – Aix-En-Provence – Nov /17 Atmospheric input to surface waters (Bonnet and Guieu, JGR, 2006) Cumulated deposition of DFe from anthropogenic aerosols from Saharan aerosols DFe (above-below thermocline) Dissolved iron DFe (nM) May June July August Sept. Oct. In the period of surface water stratification, deposition explains the dissolved iron enrichment above the thermocline (Dulac et al, Kluwer, 1996) A Saharan dust episode: about a half million of tons of dust over the Mediterranean and a deposition of grams per m 2

14 Chantier Méditerranée – Aix-En-Provence – Nov /17 Enjeu sociétal: le dépôt impacte les 1ers éléments de la chaîne trophique marine Seeding the mesocosms with 10 g m -2 of Saharan dust Increase in chlorophyll (total duration 9 d) (courtesy of Guieu et al., ANR DUNE) Impact of atmospheric deposition on marine ecosystems during marine stratification Triplicates for dust addition and for control Deppth (m)

15 Chantier Méditerranée – Aix-En-Provence – Nov /17 The huge model variability on deposition is a critical problem Global dust aerosol model intercomparison with prescribed mass fluxes, injection height and emitted particle size x 1.9 x 6.8 Adapted from AEROCOM (Aerosol Model Comparison; Textor et al., Atmos. Chem. Phys., 2006 and 2007) Dry depositionWet deposition

16 Chantier Méditerranée – Aix-En-Provence – Nov /17 ChArMEx scientific objectives Assessing the present state of the Mediterranean atmospheric environment Sources and budgets of aerosols and precursors of secondary species? - inventories of natural/anthropogenic sources - long-range transport/regional sources - trends and variability Chemical and dynamical processes? - chemical transformations, plume aging processes - air mass import/export (3D), orographic and see-breeze effects - stratification and variability in the vertical Atmospheric deposition? - soluble/insoluble - nutrients (P, N), micronutrients (Fe), contaminants (Hg) Quantifying the impacts of aerosols and reactive gases On the surface air quality (long range vs regional contributions) On the Mediterranean radiative budget and regional climate (SST, evaporation, atmospheric heating, cloud cover, heat waves, photochemistry/oxidizing capacity) On the surface ecosystems (role of deposition, perturbation of incident radiation) Predict future evolution

17 Chantier Méditerranée – Aix-En-Provence – Nov /17 ChArMEx interfaces with other projects ChArMEx-HyMeX: ChArMEx: radiative budget, impacts of its perturbations on SST, evaporation, atmospheric heating HyMEx: aerosol-cloud-precipitation interactions ChArMEx-MERMEX and ChArMEx-SICMED (not investigated yet) : ChArMEx: atmospheric deposition, perturbation of incoming solar radiation at the surface MERMEX: impacts on marine biogeochemistry, marine biogenic emissions SICMED: impacts on terrestrial ecosystems, soil and terrestrial biogenic emissions

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