Yoram Kaufman NASA/Goddard Space Flight Center

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Erin Sims
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1 Satellite observations of natural and anthropogenic aerosols effect on clouds and climate Yoram Kaufman NASA/Goddard Space Flight Center

2 Satellite observations of natural and anthropogenic aerosols effect on clouds and climate MODIS unique measurements of aerosols and clouds Application to study dust transport from Africa Can satellites measure the anthropogenic component? Smoke dust and pollution enhance cloud formation over the Atlantic Ocean

3 Satellites into polar - global orbit The launch of Terra - GSFC mission MODIS instrument

4 MODIS: Saharan dust, Jan MODIS wide spectral range: Distinguish dust from smoke / pollution aerosol Visible Fires in Australia, Dec 2001 Distinguish aerosol from land reflectance Kaufman et al., Nature 2002 Visible Mid IR Mid IR

5 Ocean algorithm: Use rough ocean reflectance model derive the optical thickness from the radiance at 0.87 µm Derive the aerosol size from the spectral dependence of the radiance Aerosol reflectance (πl/f o µ o ) dry smoke r =0.10 µm eff urban r =0.20 µm eff wet r =0.25 µm eff salt r =1 µm eff dust r =1 µm eff dust r =2.5 µm eff Tanre et al 1996,1997, Remer et al 2005 wavelength (µm)

6 Can we derive anthropogenic aerosol?

7 How do we use it? fine fraction POLLUTION f anth =0.9 MARITIME AEROSOL f f <0.05 ~0.1 ~0.2 ~0.3 ~0.4 f mar =0.2 f dust =0.5 τ m =0.06 DUST ~0.5 ~0.6 ~0.75 ~ Aerosol optical thickness

8 f pollution f dust f marine fine fraction POLLUTION f anth =0.9 MARITIME AEROSOL f f <0.05 ~0.1 ~0.2 ~0.3 ~0.4 f mar =0.2 f dust =0.5 τ m =0.06 DUST ~0.5 ~0.6 ~0.75 ~ τ mar Aerosol optical thickness τ anth = [(f tot - f dust )τ tot - (f mar - f dust )τ mar ]/(f anth -f dust ) ; =τ anth /τ total

9 Dust transport and deposition observed from Terra-MODIS Back to African dust: Publication rate on Saharan dust - ISI citation index. Background -MODIS aerosol optical thickness for July Kaufman et al., JGR Feb 2005

10 Monthly evolution of dust (green) and smoke (red) from Africa

11 total aerosol dust only W W W 10 8 average optical thickness wind westward (m/s) month

12 Dust deposition rates (tg/month) in 2001: MODIS measurements and chemical transport models for the region (0-40 N). 230±80 tg of dust left Africa at 20 S-30 N ±40 tg are deposited in the Atlantic Ocean, - 40±15 tg reach the Amazon Basin - explain the Amazon fertilization paradox - 70±25 tg arrive to the Caribbean. - 30±10 tg return to Africa and Europe

13 Application to 2 years of MODIS data? 0.2 MODIS AOT MODIS AOT-anth Aerosol optical thickness aerosol optical thickness anthropogenic optical thickness month since 2001

15 Comparison of MODIS AOT to MODELS 0.2 MODIS AOT GOCART AOT LMDZ AOT SPRINTAS-AOT Aerosol optical thickness aerosol optical thickness anthropogenic optical thickness month since 2001

16 0.2 MODIS AOT MODIS AOT-anth GOCART AOT LMDZ AOT SPRINTAS-AOT Aerosol optical thickness aerosol optical thickness anthropogenic optical thickness month since 2001

17 0.2 MODIS AOT MODIS AOT-anth GOCART AOT GOCART AOT-anth LMDZ AOT LMDZ AOT-anth SPRINTAS-AOT SPRINTAS-AOT-anth Aerosol optical thickness aerosol optical thickness anthropogenic optical thickness MODIS GOCART LMDZ SPRINTAS month since 2001

18 aot anth MODIS aot MODIS latitude ( ) Aerosol optical thickness

19 aot anth MODIS aot anth GOCART aot anth LMDZ aot MODIS aot-gocart aot LMDZ latitude ( ) Aerosol optical thickness

20 aot anth MODIS aot anth GOCART aot anth LMDZ aot MODIS aot-gocart aot LMDZ latitude ( ) Aerosol optical thickness

21 The Atlantic Ocean - 4 laboratories for simultaneous study of aerosol-cloud interaction June-Aug Pollution - interaction with clouds plays at >30N Dust - interaction with clouds performs at 5N to 30N Smoke - interaction with clouds is staged at 20S-5N Maritime aerosol - interaction with clouds, 20S-30S

22 Aerosol indirect effects: The Atlantic Laboratory: Aerosols: Red - pollution and smoke Green - dust and sea salt pollution dust smoke Sea salt Clouds: Red - low level clouds including stratiform cloudd Green - convective clouds convective convective stratiform

23 Dust Stratiform Cloud Fraction N June-Aug <AOT< <AOT< <AOT< <AOT<0.4 Stratiform Cloud Efffective radius N June-Aug <AOT< <AOT< <AOT< <AOT<0.4 Stratus and trade cumulus Clouds Smoke Stratiform Cloud Fraction <AOT< <AOT< <AOT< <AOT<0.4 Longitude Longitude Stratiform Cloud Effective Radius (µm) Longitude Longitude

24 0.8 Meteor. cond. for lowest 1/3 Meteor. cond. for highest 1/ cloud fraction N Cl-Temp=292.5, VGRD:1000 mb =0,-4m/s VGRD7500 mb =0,-2m/s longitude=51w,31w Effective radius aerosol optical thickness aerosol optical thickness 1 22 Meteor. cond. for lowest 1/3 Meteor. cond. for highest 1/3 20 S-5 N cloud fraction Effective radius Cl-Temp=291.2, VGRD:1000 mb =3.8, 4.8m/s UGRD500 mb =-4.1,-0.3m/s longitude=25w,52w aerosol optical thickness aerosol optical thickness

25 Aerosol radiative effect at TOA (-W/m 2 ) - instantaneous

26 Conclusions: MODIS observations oine and coarse aerosol allows us to distinguish dust from anthropogenic pollution and smoke We can measure the rate of transport and emission of major aerosol types Measurements of clouds and near by aerosol indicates large impact of aerosols on the cloud cover It is possible to build satellite instrument that will have much better ability to derive aerosol properties We anticipate the launch of lidars to give us the third dimension Combination of regional cloud resolved models and aerosol chemical transport models, based on in situe measurements, together with the satellite data may help resolve the effect of aerosol on climate

Saharan Dust Aerosols Detection Over the Region of Puerto Rico

1 Saharan Dust Aerosols Detection Over the Region of Puerto Rico ARLENYS RAMÍREZ University of Puerto Rico at Mayagüez, P.R., 00683. Email:arlenys.ramirez@upr.edu ABSTRACT. Every year during the months