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

Chantier Méditerranée – Aix-En-Provence – Nov. 2008 1/17

1. Main regional stakes- Ambient air quality- Chemistry-climate interactions- Impact on ecosystems

2. Scientific objectives3. Interfaces with other projects

ChArMEx

The Chemistry-Aerosol Mediterranean Experiment

Contact: [email protected]


ChArMEx is the atmospheric chemistry component of the programme: it deals with

short-lived tropospheric species

ChArMEx


Our motivationThe 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)


The Mediterranean marine atmosphere is heavily impacted by continental air

masses

Forest fires

Forest fires

Biomass burning

Volcanicsulfate

Biogenic emissions

Seasalts

Marine biogenic emissions

All types of continental and marine sources of particles and reactive gases

Forest fires


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 O3 column (DU)

Summer max.: ~+20 ppb

PREVAIR 14 July 2006 O3 peak (µg m-3)


Load

0

20

40

60

80

100

120

140

160

180

200

Mediterranean Baltic Sea North Sea Europe EuropeLand World

mg

/m2

SS

DUST

SO4

POM

BC

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…)


Enjeu sociétal: améliorer les prévisions de qualité de l’air

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)


Autre enjeu: quantifier la contribution du transport longue

distance

Corse Matin, 17 octobre 2008


Simulations of the difference in radiative flux at TOA between present and pre-industrial period, considering changes in CO2 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

CO2 forcing (min. 0.0, max. 1.0, mean +0.5 W m-2)

Indirect forcing of sulphates (min. -10.4, max. 0.9, mean -0.8 W m-2) the Mediterranean is

among the most affected regions


Aged biomass burningo = 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= 0.73-0.97):-13, -24, -37 W m-2

Non dust: -37 and -39 W m-2

(Meloni et al., JGR, 2003 and 2004)

Pollution aerosol (o= 0.83-0.89):-66 W m-2

(Roger et al., Atmos. Env., 2006)

The Mediterranean aerosols have a large impact on the solar

radiation


AOT532 =0.6o ~0.85

(Léon et al., JGR, 2002)

Direct effect

-15 to -20 W m-2

gradient <0stratification

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 >0convection

-40 to -50 W m-2

1.5 <heating<2.5 K j-1

0.5 <heating<1.5 K j-1

Semi-direct effect

20-30W m-2

March 1999

Enjeu sociétal: l’impact probable de la pollution sur le climat

régional


ACE-2ACE-219971997

ACE-1ACE-119951995

ACE-3ACE-32001-032001-03

INDOEXINDOEX1998-991998-99

SCAR-BSCAR-B19951995

TARFOXTARFOX19961996

SCAR-CSCAR-C19941994

SCAR-ASCAR-A19931993

SAFARISAFARI20002000

SHADESHADE20002000

AMMAAMMA2006-072006-07

PRIDEPRIDE20002000

ABCABC2005-082005-08

MINOSMINOS20012001

0 Polder Aerosol Index (March 1997) 0.5

Chemistry/aerosol-climate interaction studies are based on regional

experiments

ChArMExChArMEx

Journées IPSL Méditerranée, Jussieu, 25-26 oct. 2007

EUCAARIEUCAARI

The western Med has been neglected up to now


Atmospheric input to surface waters

(Bonnet and Guieu, JGR, 2006)

Cumulated deposition of DFe from anthropogenic aerosols from Saharan

aerosols DFe (above-below thermocline)

Dis

solv

ed ir

on

DF

e (n

M)

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 m2


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 fordust addition and for control

Dep

pth

(m)


The huge model variability on deposition

is a critical problem

0

100

200

300

400

500

600

700

800

wet

dep

ositi

on (M

t/yr)

ULAQ MozGN GISS LSCE UIO_CTM MATCH

0

200

400

600

800

1000

1200

1400

1600

dry

depo

sitio

n (M

t/yr)

MATCH UIO_CTM GISS LSCE MozGN ULAQ

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; http://dataipsl.ipsl.jussieu.fr/cgi-bin/AEROCOM/; Textor et al., Atmos. Chem. Phys., 2006 and 2007)

Dry deposition Wet deposition


ChArMEx scientific objectivesChArMEx scientific objectivesAssessing 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


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 andChArMEx-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

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

Documents

chantier mditerrane

increased emissions

mediterranean aerosols

anthropogenic aerosol

pollution aerosol o

emissions of biogenic

mermexsicmed slide

solar radiation slide