Current status of GEMS- Aerosol Olivier Boucher (LOA / CNRS / USTL) + aerosol partners

GEMS coordinating meeting - Reading - 15 December 2003

Current status of GEMS-Aerosol

Olivier Boucher (LOA / CNRS / USTL)+ aerosol partners


Rationale

* new studies on aerosol effects on health and ecosystems* construction of GMES ==> users

- DAEDALUS “survey of aerosol users”- ESTEC users workshop

* Integrated Global Atmospheric Chemistry Observation Strategy (IGACO) presented to IGOS partners

European added value

Socio-economic benefits

Heritage PHOENICS, CREATE-DAEDALUS, BACC_to_BACC


GEMS

Threefold objective of GEMS-aerosol:

1/ to provide operational aerosol products for a variety of end-users GMES – Climate Change

2/ to improve weather forecasts is it covered in the call?

3/ to fulfil the needs for aerosol products from the other sub-projects of GEMS

a strong justification for an integrated project


Aerosol products are well identified:

- aerosol products for end-users (analysis & forecasts)* 4D distribution of atmospheric aerosols at 50-100 km resolution* aerosol properties for all sorts of atmospheric corrections* concentrations of PM for air pollution related issues* initial and boundary conditions for smaller-scale air quality models* visibility range (e.g., air traffic, tourism)* photosynthetically available radiation (for e.g. CO22 cycle)* aerosol deposition flux (impact on vegetation, acid rain)

- aerosol products for the other sub-projects* aerosol properties for atmospheric corrections (LAND/GG/OCEAN)* photosynthetically available radiation (LAND / OCEAN)* aerosol properties for heterogeneous chemistry (RG)* aerosol properties for photolysis rates (RG)* aerosol deposition flux over the ocean (OCEAN)

further aerosol products may be defined during the project.


The bias in the OLR is significant in W.

Africa.

It is of similar magnitude to the

maximum difference in the OLR over deep

clouds associated with the ITCZ (but

opposite sign).

From J. Haywood, MRF, UKMO


Current participations in GEMS-aerosol

LOA: direct model, 1D/4D-VAR, satellite data(connection to MODIS), coordination

MPI-Hambourg: direct model, natural sources, cloudsMRF-UKMO: validation from field campaigns? University of Köln: 4D-VARFMI: assimilation of fires?, use of aerosol products for

regional AG models+ECMWF (integration, 4D-VAR, …)!--------------------------------------------------------------------------Small additional participation for | + Real-time firesnatural and anthropogenic emissions | (ESA/ESRIN)stratospheric aerosols? | + Prepared dataset+ LSCE-aerosol (AEROCOM) | of clear-sky MODIS

| radiances


Our practical goal is to implement an aerosol module in the ECMWF model with data assimilation to be run inanalysis and forecast modes.

* LMDZ-aerosol model (LOA) - aerosols decoupled from the physics- 10+ prognostic variables, bin scheme- positively evaluated in AEROCOM

* ECHAM5 aerosol model (MPI-Hamburg)- more coupling with the physics - 20+ prognostic variables, modal scheme - more possibility for linking with cloud physics- more in research mode than LMDZ


Description of LMDZ-aerosol• Sulfate: DMS, SO2, sulfate

• Black Carbon (BC) : Hydrophobic BC, Hydrophilic BC

• Organic Matter (OM): Hydrophobic BC, Hydrophilic OM

• Mineral Dust : Sub-micron, Super-micron (on-line parameterization, M. Schulz/Y. Balkanski)

• Sea-Salt : up to 20 µm in radius at 80% RH, 5 size bins in sub-micronic range; 5 size bins in 1-20 µm range [Monahan, 1986].

• Dry deposition through prescribed dry deposition velocities. Constant values for all surfaces except for sulphur species.

• Sedimentation for super-micronic sea-salt and dust only.

• Scavenging: In-cloud – treated separately for stratiform and convective precipitation [Giorgi and Chameides, 1986], for all species except hydrophobic BC and OM.

Below-cloud – treated separately for stratiform and convective precipitation, for all species.

• Convective transport: Tiedtke [1989] but a fraction of gases and aerosols released in the environment from the updrafts is scavenged.


LMDZ-AERONET comparison


LMDZ-MODIS

comparison

AOD (@ 550 nm)


ECHAM5( Roeckner

et al., in prep.) Size-Dependent Dry- and Wet-Deposition

(Ganzeveld et al., 1998; Slinn and Slinn, 1982; Feichter et al., 1996; ...)

Online emissions of Dust, Sea Salt and DMS(Tegen et al., 2002; Schulz et al., 2002; Kettle and Andreae, 2000;...)

Sulfur Chemistry(Feichter et al., 1996)

Aerosol Microphysics M7 (Vignati, Wilson, and Stier, in preparation)

• Nucleation of sulfate particles• Condensation of sulfate on existing particles• Coagulation• Transfer from insoluble to soluble modes• Thermodynamic equilibrium with water vapour

Cloud Microphysics(Lohmann and Roeckner, 1996; Lohmann et al., 1999; Lohmann and Kärcher, 2002)

Radiation Module(Boucher and Stier)


ECHAM5 - Aerosol Representation

Resolve aerosol distribution by 7 log-normal modes

Each mode is described by three moments:

Number, Median Radius Mass, Standard Deviation (fixed)

Number of transported tracers to 28

Mixing State:

AITKEN(0.005 µm < r < 0.05 µm)

ACCUMULATION(0.05 µm < r < 0.5 µm)

SOLUBLE / MIXED

COARSE(0.5 µm < r )

INSOLUBLE

1 N1, MSO4

5 N5, MBC, MOC

6 N6, MDU

7 N7, MDU

2 N2, MSO4, MBC, MOC

3 N3, MSO4, MBC, MOC , MSS , MDU

4 N4, MSO4, MBC, MOC , MSS , MDU

NUCLEATION(r < 0.005 µm)

MODES IN M7


Global Aerosol Optical Thickness

(1986 -1990)

(1983 -1987)

(2001-2002)


Volcanic eruptions have a strong impact on AOD

Global mean aerosol optical thickness of GACP AVHRR climatology(updated version of Geogdzhayev et al., 2002)

El Chichon Mt. Pinatubo


Science planWP1: Aerosol sources Quite some expertise alreadyWe still need - better volcanic sources (also real-time)- refined sea-salt and dust emissions- diurnal and weekly cycles of FF emissions- year-to-year variations (trend) in FF emissions - real-time BB emissions (synergy with RG)

WP2: Direct model of aerosolsQuite some expertise already (PHOENICS heritage)Adaptation to ECMWF model is neededsulfate / BC / OC / sea-salt / dust (nitrate, ammonium, SOA)bin versus modal scheme


Science planWP3: Data assimilation Quite some experience in aerosol remote sensingWe will rely on MODIS, then operational met satellitesIssues of data flow to ECMWFIssue of upscaling of satellite data to model resolutionAERONET data could be assimilated real-time

1D-VAR then 4D-VAR aerosol products then aerosol radiances? Clear-sky VIS radiances over the ocean(VIS + surface albedo over land)(IR + surface temperature over land)

All TL + ADJ codes are being developed


Science plan

WP4: Integration (ECMWF) Issues of - satellite data flow - implementation of the different system components - information exchange with other systems- delivery of products through some web interface

WP5: Validation of aerosol monitoring systemMany aerosol datasets (GAW, EMEP, AERONET, ...)Experience of AEROCOMDefinition of scores (forecast vs analysis, analysis vs in-situ)


Open issues

- how much cloud physics do we put in the sub-project?

- relatively little experience of the aerosol community in 4D-VAR : do we start assimilating aerosol products or clear-sky radiances?

- how much effort do we put on natural and anthropogenic aerosol sources?




AEROCOM

Aerosol model comparison withsatellite / AERONET / in-situmeasurements

PI: Michael Schulz/Stefan Kinne + a dozen groups interested

1996/1997 - 2000/2001

http://nansen.ipsl.jussieu.fr/aerocom

==> sessions at fall AGU (SF)and next EGU (Nice)

Documents

Current status of GEMS- Aerosol Olivier Boucher (LOA / CNRS / USTL) + aerosol partners