Observations of aerosol properties in the Mediterranean basin

(1)

ÓPTICA PURA Y APLICADA – Vol. 37, núm. 3 - 2004

Recibido: 14 september, 2004

3365

-Observations of aerosol properties in the Mediterranean basin.

Paola Formenti (1)

(1) LISA, Univ. Paris 7&12 / CNRS, France Contributors:

B. Chatenet, C, Schmechtig, S. Lafon, B. Marticorena, L. Menut, S. Alfaro LISA / CNRS, Creteil, France

F. Dulac

LISA / LSCE / CEA-CNRS, Gif-sur-Yvette, France S. Nava, P. Prati

Phys. Dept., Univ. Genoa, Italy T. Elias

CNRM, Toulouse, France A.M. Silva

CGE, Univ. Evora, Portugal All AERONET Pis in the Mediterranean (B.N. Holben, P. Goloub, D. Tanré, A. Karnieli,….

PRESENTATION

ABSTRACT:

In this presentation we will use the AERONET database to study the origin, load, and properties of aerosols in the Mediterranean basin, a small-scale coupled atmosphere–ocean system. The regional energy budget of the basin is strongly perturbed by scattering and absorption of sun light by aerosols, which result by superimposing anthropogenic and natural sources, such as vegetation and industrial combustion, urban pollution, mineral dust, and sea salt. The aerosol optical properties will depend by the extent and seasonality of this mixing; therefore, they might vary in the western and eastern parts of the basin, which are characterised by differing source distribution and circulation patterns. Special attention will be given to the role and properties of exported mineral dust.

Key words:

(2)

AERONET workshop, 11 May 2004

Observations of aerosol properties

in the Mediterranean basin

Kheops’s pyramide

Sphinx

_DUST

P. Formenti

LISA, Univ. Paris 7&12 / CNRS, France

(3)

Ad memoriam

(4)

Contributors

B. Chatenet, C. Schmechtig, S. Lafon, B. Marticorena, L. Menut, S. Alfaro

LISA/CNRS, Créteil, France

F. Dulac

LISA/LSCE/CEA-CNRS, Gif-sur-Yvette, France

S. Nava, P. Prati

Phys. Dept, Univ. Genoa, Italy

T. Elias

CNRM, Toulouse, France

A. M. Silva

CGE, Univ. Evora, Portugal

(5)

Modeling the dust cycle

Erosion threshold

Emission

Source areas and

periods

Emission fluxes

Concentration fields

Size distribution

Mineralogy, shape

Saltation

Sandblasting

Outputs

Surface

roughness

Soil wetness

Soil size

distribution

Surface coverage

Wind speed

Inputs

Optical properties

Direct forcing

Transport

(advection, convection, dry/wet deposition, MIXING)

Scattering/absorption

Dust Production Model (DPM)*

* Marticorena and Bergametti, 1995

(6)

How to predict dust absorption in the atmosphere

How to predict dust absorption in the atmosphere?

at the global scale?

In the aerosol fraction, as a function of size

Free-Fe

_aer

= total-Fe

_aer

* [Free-Fe / total-Fe]

_soil

Soil

Aerosol

Clays

Free Fe Total Fe

R

_c

=

Fine silts

R

_s

=

Rc Rs

DPM

Size-resolved total iron content

Free-iron content

Attenuation (on filter)

Absorption

_coefficient

Soil

Aerosol

Clays

R

_c

=

Clays

R

_c

=

Free Fe

Total Fe Free Fe Total Fe

R

_c

=

Fine silts

R

_s

=

Fine silts

R

_s

=

Free Fe

R

_s

=

Rc Rs

DPM

Free-iron content

Attenuation (on filter)

Absorption

_coefficient

The free-to-total Fe ratio depends on soil type

Ä it can be mapped!

Æ

R seems to be conserved from soil to aerosol

Size distribution Dust Production Model

This work!

at the global scale?

In the aerosol fraction, as a function of size

Free-Fe

_aer

= total-Fe

_aer

* [Free-Fe / total-Fe]

_soil

Soil

Aerosol

Clays

R

_c

=

Fine silts

R

_s

=

Rc Rs

DPM

Free-iron content

Attenuation (on filter)

Absorption

_coefficient

Soil

Aerosol

Clays

R

_c

=

Clays

R

_c

=

Free Fe

R

_c

=

Fine silts

R

_s

=

Fine silts

R

_s

=

Free Fe

R

_s

=

Rc Rs

DPM

Free-iron content

Attenuation (on filter)

Absorption

_coefficient

Æ

Soil

Aerosol

Clays

R

_c

=

Fine silts

R

_s

=

Rc Rs

DPM

Free-iron content

Attenuation (on filter)

Absorption

_coefficient

Soil

Aerosol

Clays

R

_c

=

Clays

R

_c

=

Free Fe

R

_c

=

Fine silts

R

_s

=

Fine silts

R

_s

=

Free Fe

R

_s

=

Rc Rs

DPM

Free-iron content

Attenuation (on filter)

Absorption

_coefficient

Æ

Soil

Aerosol

Clays

R

_c

=

Fine silts

R

_s

=

Rc Rs

DPM

Free-iron content

Attenuation (on filter)

Absorption

_coefficient

Soil

Aerosol

Clays

R

_c

=

Clays

R

_c

=

Free Fe

R

_c

=

Fine silts

R

_s

=

Fine silts

R

_s

=

Free Fe

R

_s

=

Rc Rs

DPM

Free-iron content

Attenuation (on filter)

Absorption

_coefficient

Æ

This work!

Lafon et al., 2004

(7)

Modeling the dust cycle :

Resolution

- Horizontal : 3 domains (1x1°, 0.5x0.5°, 6 km)

- Vertical : 10–30 levels (surface to 200 hPa)

Meteorological field

- ECMWF and/or NCEP pour large resolution

- MM5 for mesoscale

Dust emission

DPM

(

Marticorena and Bergametti,

1995;

Alfaro and Gomes,

2001)

Simulations

Climatology 1991–2001 (hourly resolution)

Validation

- Satellites

- Lidars

(8)

Modeling the dust cycle : preliminary results

May 1991 : simulated optical depth

(9)

Modeling the dust cycle : validation

CACHE (ground-based)

El Cairo, Oct 2004 - Mar 2005

Dust / urban pollution

PI : LISA

ADRIEX (airborne)

Adriatic/Black Sea, Aug-Sep 2004

Urban / industrial pollution, fires

PI : UK Metoffice

AMMA (ground-based and airborne)

Niger, 2005–2007 (intensive 2006)

Dust / biomass burning

PIs : LISA, LOA, LA, CNRM

(10)

AMMA, emissions and properties of Sahelian dust

0

1

2

3

4

5

6

7

0

90

180

270

360 Column water

c

ontent, c

m

0

1

2

3

4 AOD, 870 nm

Jan

_Apr

_Jul

_Sep

_Dec

(11)

DLR-F / Falcon20 Niamey Flight Ranges

F / ATR 42 Niamey Flight Ranges

UK Bae-146 Dakar Flight Ranges

M’Bour

Banizoumbou Segou

Lamto

AERONET sites

EOP, 2005-2007

Mass concentration

Wet/dry deposition

Vertical profiles

(12)

Observations in the Mediterranean

Venise

ADRIEX

CACHE

Poster by Chaabane et al.

Talk by Yvgeni et al.

Oristano

Thala

Moldova

Sde Boker

Erdemli

Poster by Aculinin et al.

El Arenosillo

• Frequency and properties of dust (

vertical profiles

)

(13)

Vertical profiles : dust

Offshore Senegal

Eastern Mediterranean

Extinction coeff (km-1₎

Dulac et al., 2002

(14)

Vertical profiles : vegetation burning and industrial

pollution

(15)

Vertical profiles : vegetation burning and industrial

pollution

(16)

Frequency of dust

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Angstrom<0.5 0.5<Angstrom<0.8 Angstrom>0.8

AOD

, 870 nm

Eastern Med (Erdemli) Central Med (Oristano)

July 2000-May 2001

0 10 20 30 40 50 60 70 80 90 100

Fr

equenc

y,

%

Eastern Med (Erdemli) Central Med (Oristano)

July 2000-May 2001

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

AOD

, 870 nm

Western Med (El Arenosillo) Central Med (Oristano)

Aug 2001-Dec 2002

0 10 20 30 40 50 60 70 80 90 100

AOD

, 870 nm

Western Med (El Arenosillo) Central Med (Oristano)

Aug 2001-Dec 2002

Frequency, %

(17)

0 0.5 1

0 90 180 270 360

Years 2000-2003

AOD, 870 nm Angstrom exp

Jan Apr Jul Sep Dec

Monthly mean (1984-1994) dust optical depth at 550 nm, METEOSAT

Moulin et al., 1998

Seasonality of dust

(18)

Seasonality of dust

0 0.5 1

0 90 180 270 360

Years 2000-2002

Jan Apr Jul Sep Dec

0 0.5 1

0 90 180 270 360

Years 2000-2002

Jan Apr Jul Sep Dec

Monthly mean (1984-1994) dust optical depth at 550 nm, METEOSAT

Moulin et al., 1998

Western Med (Arenosillo)

(19)

Single scattering albedo, Central basin

y = 0.04x + 0.96 R2 = 0.71

0.9 0.95 1 1.05 1.1

0 0.5 1 1.5 2

Angstrom exponent

Ra

tio

0

(4

41

)/

0

(8

70

)

Spherical

Aspherical

Ra

tio

ω0

(440

) /

ω0

(870

)

0.85 0.9 0.95 1

0 0.5 1 1.5 2

Angstrom exponent

0

(670)

Spherical Aspherical

ω

₀

at 670 nm ~ 0.91 – 0.99

(20)

Single scattering albedo, Central basin

0.8 0.85 0.9 0.95 1 1.05

0 0.5 1 1.5 2

Angstrom exponent Ra tio 0 (4 41 )/ 0 (8 70 ) Spherical Aspherical

Thala

y = 0.04x + 0.96 R2 = 0.71

0.9 0.95 1 1.05 1.1

0 0.5 1 1.5 2

Angstrom exponent Ra tio 0 (441) / 0 (870) Spherical Aspherical Ra tio ω0 (440 ) / ω0 (870 ) Ra tio ω0 (440 ) / ω0 (870 )

Oristano

(21)

Single scattering albedo, Thala

0.7

0.8

0.9

1

300

500

700

900 1100

Wavelength, nm

S

ingle s

ca

tter

ing albedo

23 Sept 2001

Nigerian soil

Tunisian soil

Alfaro et al., 2004

-15

-10 _-5

0 5 10 15 20 25 30 35 40 45 ★ ▲ ▼ ▲ ▲_▲_▼▲ ▲ ▲ ▼ ▲ ▲ ★ ■ ❏ ■ ■ ■ ❏ ■ ■ ■ ❏■ ■ ★ ● ❍ ● ● ● ❍ ● ● ● ❍ ● ● ★ ▲ ▼ ▲ ▲ ▲ ▼ ▲ ▲ ▲ ▼ ▲ ▲ ★ ■ ❏ ■ ■ ■ ❏ ■ ■ ■ ❏ _■ ■ ★ ● ❍ ● ● ● _❍ ● ● ● ❍ ●

● 500 1000 1500 2000 2500 3000 50 1500 3000 06 00 06/16

18 12 06 00 06/15

18 12 06 00 06/14

18 12

NATIONAL OCEANIC ATMOSPHERIC ADMINISTRATION

Backward trajectories ending at 12 UTC 16 Jun 01

FNL Meteorological Data

Source

★

at 35.50 N 8.60 E

Meters AGL

-30

-15 ₀ 15

30 15 30 45 ★▲▼_▲▲▲▼▲▲▲▼▲ ▲ ★ ■ ❏ ■ ■ ■ ❏ ■ ■ ■ ❏ ■ ■ ★ ● ❍ ● ● ● ❍ ● ● ● ❍_● ● ★ ▲ ▼ ▲ ▲ ▲ ▼ ▲ ▲ ▲ ▼ ▲ ▲ ★ ■ _❏ ■ ■ ■ ❏ ■ ■ ■ ❏ ■ ■ ★ ● ❍ ● ● ● ❍ ● ● ● ❍ ● ● 500 1000 1500 2000 2500 3000 3500 50 1500 3000 06 00 09/23

18 12 06 00 09/22

18 12 06 00 09/21

18 12

NATIONAL OCEANIC ATMOSPHERIC ADMINISTRATION

Backward trajectories ending at 12 UTC 23 Sep 01

FNL Meteorological Data

Source

★

at 35.50 N 8.60 E

Meters AGL

(22)

Single scattering albedo, Western basin

0.85 0.9 0.95 1

0 0.5 1 1.5 2

Angstrom exponent

0

(6

70)

Spherical

Aspherical

y = 0.06x + 0.95 R2 = 0.79

0.9 0.95 1 1.05 1.1

0 0.5 1 1.5 2

Angstrom exponent

Ra

tio

≅0

(441)

/≅0

(870)

Spherical

Aspherical

ω

₀

at 670 nm ~ 0.96 – 0.99

(23)

Single scattering albedo, Eastern basin

ω

₀

at 670 nm ~ 0.95 – 0.99

0.9 1 1.1 1.2

0 0.5 1 1.5 2

Angstrom exponent

Ra

tio

0

(4

41

)/

0

(870

)

0.85 0.9 0.95 1

0 0.5 1 1.5 2

Angstrom exponent

0

(670)

(24)

Single scattering albedo, Eastern basin

ω

₀

at 670 nm

0.85

0.95

0

90

180

270

360 Spherical

Aspherical

Dec

Jan

Apr

Jul

Aug

(25)

Vegetation burning

2nd half August 2002

January 2002

(26)

Profiles of chemical composition

0 1000

2000

3000

4000

0.01

0.1

1

10 BC

_E

-to-nss-SO

₄

ratio

Altitude, m

STAAARTE-97

STAAARTE-98

Crete 10 June 1997

Crete 18 August 1998

Thessaloniki 14 August 1998

Sciare et al., 2003

Dulac et al., 2002 Formenti et al., 2001

(27)

Aerosol sulfate measurements

Western Med

Central Med

Eastern Med

7.5 Malta

Barcelona

Spain (Granada)

Israel

Turkey *

Turkey

Crete *

Crete (STAAARTE-97)

Thessaloniki (STAAARTE-98)

Crete (STAAARTE-98)

6.7 (1.5 – 14)

9.9 (1.5 – 23)

10.5 2.2 (2)

7.3 (6.5)

2 – 8

7.9 (1.4)

2.1 (0.9)

2.4 (1.1)

Mean PM

₁₀

SO

₄

(µg m

–3

₎

* Full year; summer only otherwise

(28)

August 1998 : Comparison AOD

τ

_a

= 0.23

0

0.1 0.2

01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 0

0.1 0.2 0.3 0.4

01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

0 0.1 0.2 0.3 0.4

01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 0

0.1 0.2 0.3 0.4

01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

τ

_a

~ 0.30

τ

_a

~ 0.10

τ

_a

~ 0.10-0.30

τ

_a

~ 0.05

Forster et al., 2001

(29)

Comparison of single scattering albedo

0.75

0.8

0.85

0.9

0.95

1

400

500

600

700

800

900 1000

1100

Wavelength, nm

Single s

ca

tter

ing albedo

STAAARTE-98

(30)

Comparison size distribution

0.0001

0.001

0.01

0.1

1

0.01

0.1

1

10

100 Radius, µm

dV/dlnR, µm

STAAARTE-98, PCASP integrated between 0 and 4 km

Ispra

0.0001

0.001

0.01

0.1

1

0.01

0.1

1

10

100 Radius, µm

dV

/dlnR, µm

Sde Boker

(31)

Scattering time series, Granada, VELETA 2002

Talk by Alados Arboletas and various posters

0

100

200 7 Jul

9 Jul

11 Jul 13 Jul 15 Jul 17 Jul 19 Jul 21 Jul 23 Jul

July 2002

Sc

att c

oeff,

Mm-1

Scatt coeff, calc (Al, S)

Scatt coeff, meas

M = Mediterranean flow A = Atlantic flow

Dust

(32)

Scattering time series, Granada, VELETA 2002

Talk by Alados Arboletas and various posters

0

100

200 7 Jul

9 Jul

11 Jul 13 Jul 15 Jul 17 Jul 19 Jul 21 Jul 23 Jul

July 2002

Sc

att c

oeff,

Mm-1

Scatt coeff, calc (Al, S, BCE)

Scatt coeff, meas

(33)

Scattering and AOD time series

0

100

200 7 Jul

9 Jul 11 Jul 13 Jul 15 Jul 17 Jul 19 Jul 21 Jul 23 Jul

July 2002

Sc

att c

oeff, Mm-1

0

0.1

0.2

0.3

0.4

0.5

0.6 AO

D, 440 nm

Scatt coeff, calc (Al, S)

(34)

The episode of 13-14 July

(35)

The episode of 13-14 July

(36)

There is no conclusion!

We are collecting data

0 2 4 6 8 10

1 10 100 1000

Estimated dust mass, µg m-3

Fe

conte

n

t, %

Range 4-7 %

0 2 4 6 8 10

1 10 100 1000

Estimated dust mass, µg m-3

Fe content, %

Range 2-6%