Instrumented high- perf. Ultra Light AircraftForward/ nadir pointing back-scattering lidar (355 nm), PTU,scatterometer (880 nm), GPS,artificial horizon

(Chazette et al., ILRC23, 2006)

4. New toolsA number of unprecedented experimental and modelling tools are now available,

e.g.:

Quasi- real t ime spaceborne monitoring and model transport forecasting of aerosol for intensive f ield observat ions on alerts CHIMERE- DUST LMDZ- INCA: aerosol and reactive gases GIRAFFE: smoke plumes from active fires MSG/ SEVIRI hourly quicklooks and products(http:/ / euler.lmd.polytechnique.fr/ menut/ chimeredust/ index.html) (http:/ / www- lsceinca.cea.fr/ welcome_real_time.html) (http:/ / aoc.amma- international.org/ archive/ (http:/ / www.icare.univ-lille1.fr/ )

researchProduct/ aerosol- chemistry/ girafe/ )

Extensive coincident observations from space, including vert ical aerosol distribut ion The A- Train: Aerosol products (CALIOP, PARASOL aerosol optical depth at 865 nm (June 2006 ave.) CALIOP: aerosol backscatter profile (532 nm) MSG- SEVIRI: aer. optical depth and MODIS, OMI, PARASOL) and others large non spherical aerosols submicronic mode (http:/ / www- calipso.larc.nasa.gov/ calipso_browse) Angström exponent (26 June 2006) (http:/ / www.icare.univ- lille1.fr/ ) (http:/ / www.icare.univ- lille1.fr/ )

Airborne payloads

Isokinetic probes for in situ aerosol sampling and measurements of submicron and dust part icles, and cloud interst it ial part icles AVIRAD (3- λ nephelometer, 7- λ aethalometer, CVI and Community Inlet (Lyman- α, CN and optical counter/ sizer, impactor + 2 filters) CCN counters, PSAP, DMSP, V- DMSP, OPC)

D. African dust has a major impact on air quality in rural sites and signif icantly impacts urban sites

E. In the period of surface water strat if icat ion, atmospheric deposit ion explains the dissolved iron (DFe) enrichment above the thermocline. This likely favours diazotrophic populat ions such as cyanobacteria

(Bonnet and Guieu, JGR, 2006)

Im pacts of intense aerosol episodes in the western M editerranean regionCollectif Aérosols :

Stéphane Alfarog, Yves Balkanskil, Gilles Bergamettig, Isabelle Chiapelloi, Karine Deboudtb,  Karine Desboeufsg, Serge Despiaum, François Dulacl,g,Cyrille Flamantn,  Pascal Flamentb,  François Gheusid,  Philippe Goloubi,  Laurent Gomesa,  Cécile Guieuk,  Jean- Luc Jaffrezof,  Michel Legrandi,

Jean- François Léoni, Rémi Losnog, Marie- Dominique Loÿe- Pilotc, Marc Malletd, Nicolas Marchande, Béatrice Marticorenag, Laurent Menuth,Christophe Migonk, Cyril Moulinl,  Jacques Pelonn,  Mai Pham l,  François Ravettan,  Didier Tanréi,  Sylvie Thiriaj, Henri Worthame

aCNRM- Toulouse, bELICO- Wimereux, cENS/ CERES- Paris, dLA- Toulouse, eLCE- Marseille, fLGGE- Grenoble, gLISA- Créteil,hLMD- Palaiseau, iLOA- Lille, jLOCEAN- Paris, kLOV- Villefranche- Sur- Mer, lLSCE- Saclay, mLSEET- Toulon, nSA- Paris

Contact: francois.dulac@cea.fr

(see also posters by Gheusi and Ravetta, and by Guieu et al.)

Poster H14, 1st HyM eX W orkshop, Toulouse, 9­11 Jan. 2007 

2. Abstract. Our objective is to assess the various impacts of transport and deposition of high aerosol episodes (desert dust, forest fires, anthropogenic pollution) which are frequent in the western Mediterranean and likely become more frequent with climate change.Although the European (and part icularly the French) scientif ic community has a signif icant background in aerosol studies in the Mediterranean, the expected signif icant impacts of these high aerosol episodes are yet poorly documented. We include impacts on:- the radiative budget (heat waves, photochemistry, Med. Sea energy budget, cloud cover, …);- marine biogeochemistry (nutrient and micronutrient inputs);- air quality (PM threshold exceeds).We suggest an integrated mid- term national strategy to address these impacts. A preliminary f ield study of mineral and organic aerosol opt ical and hygroscopic propert ies in Corsica is proposed in conjunction with aerosol remote sensing. It would also help to set up an atmospheric aerosol and chemistry observatory in Corsica (poster by Gheusi et al.). Air quality data analysis and regional model simulat ions would be performed to check the frequency of high PM events in selected places (e.g. Marseille- Berre) and the contribut ion of desert dust. The chemical characterizat ion of anthropogenic and dust aerosols including assessment of their deposit ion and laboratory study of their solubility would also be performed in collaborat ion with init iat ives for fert ilizat ion experiments (e.g. poster by Guieu et al.).In the longer term, modelling, experimental work and satellite remote sensing will address the regional scale including the whole western Mediterranean and nearby countries. We suggest that a large coordinated summer f ield experiment that could be part of HyMEx, involving a surface network of stat ions, ship and aircraft measurements, could cope with the needs of both the study of large- scale intense aerosol episodes and modulation of the energy budget at the surface, and of an in situ mesoscale marine fert ilizat ion with aerosols.

1. Context. At the INSU Ocean- Atmosphere prospective workshop of Lille in Nov. 2005, it was concluded on the interest of the Mediterranean region for a post- AMMA mult i- scale and mult i- disciplinary coordinated programme with possible focus on: - the hydrological budget of the Mediterranean; - intense events; - climate change and anthropogenic pressures.

The project HyMeX addresses the hydrological budget and considers related intense events such as heavy rainfall and floods. The region, however, is submitted to intense aerosol events, the various impacts of which are not yet quantified and are mostly out of the scope of HyMeX.

A major part of the French aerosol community declares its interest for a coordinated study of the western Mediterranean aerosols with the most recent instrumental techniques and models, that could be part of HyMeX.

B. The seasonal variability is controlled by precipitat ion and cyclogenesis

C. In summer, in addit ion to dust transport, forest f ires contribute to the maximum

load of absorbing aerosols (ωo down to 0.8, Meloni et al., ACP, 2005) which decrease surface evaporat ion and modify the thermal vert ical gradients

1998- 2003 average of SeaWiFS-derived aerosol optical depth at 865

nm(Antoine and Nobileau, JGR, 2006)

0 Polder Aerosol Index (March 1997) 0.5

POLDER data: CNES & NASDAProcessing: LOA & LSCE

Due to the variability of aerosol properties, aerosol- climate interactions are addressed through extensive regional programs

and campaigns

The western Mediterranean has been neglected up to now!

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

MODIS- derived episodes of large forest fire plumes affecting the western Med.

(Pace et al., JGR, 2005)

Fraction of annual burned area in July-August

(http:/ / www.promethee.com/ prom/ stats)

*heat wave

Year Period AOT550 Angstr. Exp.2000 20-23 July 0.21±0.04 1.39±0.222001 25-29 July 0.24±0.09 1.23±0.252002 27-30 July 0.16±0.15 1.51±0.26

20038-12 July

4-14 August*0.22±0.060.21±0.04

1.42±0.101.53±0.12

2004 15-17 August 0.11±0.05 1.48±1.01 0%

20%

40%

60%

80%

100%

1970 1975 1980 1985 1990 1995 2000 2005

Haute Corse All French Med. Dépts.

AOTRain

(m m h -

1)

June

Apr.

Aug.

0.30

0.20

0.15

0.10

0.05

0.00O.D.

0

15

20

30

50

Fr. (%)

L H

L

L

H

L

Mean AOT

ov er s ea

High dus t occurrence ov er land

%

1984- 1994 averages from Meteosat for aerosols, and 1979- 1988 from AMIP for precipitation

(Moulin et al., JGR, 1998)

Mar

ine

mix

ed l

ayer

dep

th (

m)

Mixed layer depth

Anthropogenic aerosols

Saharan sources

Atm

osp

her

ic d

epo

siti

on

of

DFe

in

th

e M

L (n

M)

Cumulated deposition of DFe

from anthropogenic aerosols

from Saharan aerosols

Delta DFe (above- below thermocline)

Dis

solv

ed i

ron

DFe

(n

M)

May June July August Sept. Oct.

3. Some facts

Minima rains

Peaks African dust

Dry season: highbackground

Wet season: lowbackground

EU PM10 threshold

Daily atmospheric concentrations in particulate Si at a rural coastal site in Corsica(Bergamett i et al., Kluwer, 1989)

During a low dust year in Thessaloniki (2nd city of Greece), African dust occurred during 4/ 10 th

of the 40% of days with the highest column AOT865nm

(Léon et al., AO, 1999)

A. African dust controls the average aerosol load in the Mediterranean

Direct effect

- 10 to - 15 W m - 2

gradient < 0 : stratification

Evaporation of low clouds(Ackerman et al., 2000)

Modification of the latent heat flux

gradient > 0 : convection

- 30 to - 45 W m - 2

1.5 < heating< 2.5 K j- 1

0.5 < heating< 1.5 K j- 1

Semi- direct effect

Impact of absorbing aerosols: the INDOEX case(Léon et al., JGR, 2002)

20- 30W m - 2

5. Proposed strategy

2007- 2008

Set- up of a monitoring observatory in Corsica

Pre- campaigns CORSICA (surface + ULA)

Preparatory modeling, remote sensing, laboratory studies

Implementation plan for a summer experiment, building of international partnerships

2009- 2010

Intensive summer experiment with intensive airborne, ship and surface observations in addition to networks,

in coordination with HyMeX and COCOMEX

(day+ 1)

(day+ 3)

(day+ 2.5)

26 June 2006, night t ime

0.0 0.5 1.0 1.5 2.0AOD550nm

0.0 1.15 2.5Angström

PLASMA Vaisala sunphotometer dropsonde

system

La Tapoa Niamey

Dust aerosol from Sahara desert

Biomass burning from Benin- Nigeria

Mixed aerosol from lack Tchad area

AMMA SOP- 0, Niamey airport

Updated aerosol- climate and - transport models

Direct atmospheric radiative forcing by Improved parameterization of the anthropogenic aerosols (BC, POM, SO4), aerosol size distribution for both averaged from nine global models deposition and optical depth (Schulz et al., ACP, 2007; (Foret et al., JGR, 2006) http:/ / nansen.ipsl.jussieu.fr/ AEROCOM)

Particle diameter (µm)

Dry

dep

osi

tio

n v

elo

city

(cm

s-

1)

reference (1000 bins)classical isolog schemenew isogradient scheme

6 size bin

case