atmosp tmospheric dust o heric dust over er Cape V Ca pe Ver - - PowerPoint PPT Presentation

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atmosp tmospheric dust o heric dust over er Cape V Ca pe Ver - - PowerPoint PPT Presentation

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Universidade de Aveiro Seaso Seasonal nal varia variability bility of of atmosp tmospheric dust o heric dust over er Cape V Ca pe Ver erde islands de islands C. Pio 1 ; M.C. Freitas 2 ; J. Cardoso 1,3 ; T. Nunes 1 ; S.M. Almeida 2 ;

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

Seaso Seasonal nal varia variability bility of

  • f

atmosp tmospheric dust o heric dust over er Ca Cape V pe Ver erde islands de islands

  • C. Pio1; M.C. Freitas2; J. Cardoso1,3; T. Nunes1; S.M. Almeida2; M.

Almeida2; O. Tchepel1; F. Rocha1; M. Cerqueira1; J. Ferreira1; D. Terroso1; ;

  • P. Fialho4; Ho Dung2; Danilo Custódio1

1- Universidade de Aveiro; 2- Instituto Tecnológico e Nuclear; 3- Universidade de Cabo Verde; 4- Universidade dos Açores

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SLIDE 2

Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

Presentation based on CVDUST project:

“CVDUST - Atmospheric aerosol in Cape Verde region: seasonal evaluation of composition, sources and transport”

  • Joint initiative of : University of Aveiro; Technological and

Nuclear Institute; Cape Verde University.

  • Support of the Cape Verde Atmospheric Observatory (CVAO).
  • Funding through Portuguese FCT .
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SLIDE 3

Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June Fine Particles Coarse Particles Sea Salt 82.1 2460 Dust 250 1000-4875 Carbon 81 Sulfate 150 Nitrate 11.3 Ammonium 33.6

Estimated Global Emission rates of particles into the Atmosphere (Tg yr-1)

  • Natural Soil;
  • Agriculture (example “Dust Bowl” in USA);
  • Transports;
  • Industry (cement; mining)

Why study atmospheric dust in Cape Verde?

ref: Raes et al., (2000)

Dust Sources:

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June http://ozoneaq.gsfc.nasa.gov/TOMSAerosol.md

TOMS satellite seasonally averaged values of Aerosol Index in the period 1980-92

NOVEMBER-JANUARY MAY-JULY

  • Sahara emissions predominate
  • Higher AI values during summer

(ref: Engelstaedter, 2006)

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

Impacts of desert dust emissions

  • Atmospheric Heat Balance and Climate Control
  • Weakening of Atlantic Tropical Cyclones
  • Biogeochemical Cycles
  • Biogeochemical Cycles in Atlantic and Amazon Basin
  • Toxic Algae Blooms
  • Human Health
  • Spreading of meningitis in Sahel (Sultan et al., 2005)
  • Kawasaki disease in Japan and Western USA (Fraser, 2012)
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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

Objectives of Project CVDUST:

  • 1. Monitoring and sampling atmospheric dust during one year
  • 2. Chemical and structural characterization of collected samples
  • Water Soluble ions
  • Carbonate and Carbonaceous forms
  • Elemental Composition (NAA)
  • Mineralogical Composition (XRD; TEM; SEM)
  • Organic Species (GC/MS)
  • Microbial and fungi characterization
  • 3. Source Identification; Transport and Deposition Modeling
  • Source Apportionment (PMF; PCA/MLRA)
  • Transport Modeling (Trajectory Analysis; DREAM Model)
  • 4. Quantify African dust input to Cape Verde Air Quality
  • 5. Explain processes governing dust production, transport, and

removal from atmosphere over the Atlantic

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

Monitoring and Sampling:

Performed at Praia airport during one year (Jan2011-Jan2012)

Equipment:

1 GRIMM Aerosol Spectromeeter (0.25->32µm) 31 channels 1 Aethalometer (7 wavelength channels) 2 PM10 LowVol filter samplers 1 PM10 HighVol filter Samplers 1 Berner LowVol impactor (0.063-16 µm) 8 stages 1 HighVol impactor (<0.49-10µm) 6 stages 1 Meteo Station

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

Special Conditions of Cape Verde to perform Sahara Dust Studies:

  • Out of West Africa Coast (900 km)
  • Dust Season Period (Bruma Seca – Dry Fog)
  • Safety and Electricity Supply
  • Good relations and Low Cost

CLEAN ATMOSPHERE BRUMA SECA – DRY FOG

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June Average dust size profile measured with the GRIMM Optical Spectrometer , for 18 Jan 2011, at Praia, Santiago Island AERONET Integrated Air Column Size Profile Dust Volume Concentration, for 18 Jan 2011, in Sal Island

Dust Size Distribution

 Dust mass mainly in size range 1-10 µm

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

 Local re-suspension processes probably responsible for dust particles above 10 µm

Hourly averaged dust size distribution variability along the day 18 Jan 2011

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

WHO Guide values

Aerosol concentration variability at Praia during 2011

Monthly Averaged Concentrations Daily Averaged Concentrations

01/01/11 01/02/11 01/03/11 01/04/11 01/05/11 01/06/11 01/07/11 01/08/11 01/09/11 01/10/11 01/11/11 01/12/11 01/01/12 01/02/12

concentração (g/m

3)

100 200 300 400 500 PM2.5 PM10 PTS Jan 11 Feb 11 Mar 11 Apr 11 May 11 Jun 11 Jul 11 Aug 11 Sep 11 Oct 11 Nov 11 Dec 11 Jan 12

concentração (g/m3)

50 100 150 200 250 300 PM2.5 PM10 PTS

Monthly Averaged Concentrations Daily Averaged Concentrations

50 25

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SLIDE 12

Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

J a n 1 1 F e b 1 1 M a r 1 1 A p r 1 1 M a y 1 1 J u n 1 1 J u l 1 1 A u g 1 1 S e p 1 1 O c t 1 1 N

  • v

1 1 D e c 1 1 J a n 1 2

nº de excedências

2 4 6 8 10 12 14 PM2.5 PM10

Parameter Annual Average* (µg/m3) WHO Guide Values (µg/m3) PM2.5 17.5 10 PM10 37.5 20 TSP 66.0

  • Nº of daily exceedences

 Particulate pollution levels clearly exceed WHO Guides and probably affect local Human Health, principally during “BRUMA SECA” Season

Particulate Pollution Levels and daily exceedences, at Praia

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

Major Chemical Class Composition of Praia Aerosol

WSII- Water Soluble Inorganic Ions

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

48 Hours backward trajectories for every day in Febr. 2011

First week Second week Third week Fourth week

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

48 Hours backward trajectories for every day in August 2011

First week Second week Third week Fourth week

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

25000 5000 10000 15000 20000 25000 1 2 3 4 5 25000 5000 10000 15000 20000 25000 10 20 30 40 50

Sm/Fe=0.00012 Sm/Fe=0.00024

[Sm] (ng.m

  • 3)

Rb/Fe=0.0018 Rb/Fe=0.0056

[Rb] (ng.m

  • 3)

)

[Fe] (ng.m-3)

Green- Sea salt composition Red- Saharan soil composition (Reguigui et al., 2002); Blue- Global soil composition (Manson and Moore (1982)

Composition relations

Source apportionment:

Na/Mg=8.3 Cl/Mg=14.9

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

DREAM - Dust REgional Atmospheric Model | BSC-DREAM8b

predicts the atmospheric life cycle

  • f the eroded Saharan desert dust

DUST PRODUCTION SCHEME:

  • Type of soil
  • Type of vegetation cover
  • Soil moisture content
  • Surface atmospheric turbulence

http://www.bsc.es/projects/earthscience/DREAM/

Emission, Transport and Deposition Modeling

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

DR DREA EAM ad adapt ptation tion/a /app pplica ication tion to to CV CV-DU DUST ST Pr Project ect

Resolution:

37 x 37 km2

24 vertical layers

(km) 15 10 5

AERONET

Sampling point

  • 26W
  • 14E

19N 13N

Outputs

  • AEROSOL CONCENTRATION
  • DUST LOAD COLUMN
  • DRY / WET DEPOSITION
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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

DREAM EAM Mo Model del ou

  • utput

put exa xampl mple

FOUR DAYS SURFACE AEROSOL CONCENTRATION, END FEBRUARY 2011

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

DR DREA EAM - Inte tercomparis comparison

  • n Model

el / M / Mea easurements ements

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

PROVISIONAL CONCLUSIONS

  • A complete chemical e physical composition seasonal data set for

atmospheric aerosol offshore of northwest Africa, gathered;

  • Clear existence of two seasons with different particulate pollution levels;
  • Particulate pollution levels clearly above WHO health guides, principally

during the “Bruma Seca” dust season;

  • Chemical composition shows two predominant aerosol sources: sea salt

spray and soil dust;

  • DREAM model can reproduce reasonably the transport of dust and the

aerosol loading in Cape Verde region;

  • Continuation of analytical and modeling work in the near future are

expected to permit further insight into source characterization and quantification and dust transport and deposition to the Atlantic.

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Universidade de Aveiro

ICEH 2012 , Lisbon 29May-1June

Thanks for your attention!

Casim simiro iro A. Pio io

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CESAM & Departamento de Ambiente Universidade de Aveiro 3810-193 Aveiro; Portugal Phone- +351-234370245 Email- casimiro@ua.pt http://www.cesam.ua.pt/cpio

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