ÓPTICA PURA Y APLICADA Vol. 37, núm. 3-2004 Aerosol Optical Properties in Southeast Asia From AERONET Observations T.F. Eck (1), B.N. Holben (1), J. Boonjawat (2), A. Snidvongs (2), H.V. Le (3), J.S. Schafer (1), T. Kaewkonga (2), R. Mongkolnavin (2), J.S. Reid (4), L.A. Remer (1), O. Dubovik (1), and A. Smirnov (1). (1) NASA / GSFC, Greenbelt, MD, USA. (2) Chulalongkorn University, Bangkok, Thailand. (3) Vietnam National Center for Natural Science and Technology, Hanoi, Vietnam. (4) NRL, Monterey, CA, USA. ABSTRACT: Characterization of aerosol optical properties. Validation of Satellite Aerosol Retrievals. Near real-time acquisition; long term measurements. Homepage access http://aeronet.gsfc.nasa.gov First Year of AERONET Monitoring in Thailand and Vietnam, with Plans for Continuing Monitoring. Mid-February to Early May, 2003 : 2nd Half of the Dry Season at 6 Sites; Entire Dry Season monitoring at 1 site Nov 2003 Present. Preliminary Analysis Based on Level 1.5 Data: Awaiting Final Calibration for More Complete Analysis (4 sites have final level 2.0 data). Preliminary data suggest that during the 2nd half of the dry season the aerosol is quite strongly absorbing in both urban and rural sites in SE Asia (w0550 ~ 0.895-0.915). Key words: AERONET, Aerosol PRESENTATION - 3491 - Recibido: 30 - september - 2004
Aerosol Optical Properties in Southeast Asia From AERONET Observations T.F. Eck 1, B.N. Holben 1, J. Boonjawat 2, A. Snidvongs 2, H.V. Le 3, J.S. Schafer 1, T. Kaewkonga 2, R. Mongkolnavin 2, J.S. Reid 4, L.A. Remer 1, O. Dubovik 1, and A. Smirnov 1 1 NASA / GSFC, Greenbelt, MD, USA 2 Chulalongkorn University, Bangkok, Thailand 3 Vietnam National Center for Natural Science and Technology, Hanoi, Vietnam 4 NRL, Monterey, CA, USA Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3492
AERONET-An Internationally Federated Network Characterization of aerosol optical properties Validation of Satellite Aerosol Retrievals Near real-time acquisition; long term measurements Homepage access http://aeronet.gsfc.nasa.gov Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3493
AERONET Monitoring of Aerosol Optical Properties in SE Asia First Year of AERONET Monitoring in Thailand and Vietnam, with Plans for Continuing Monitoring Mid-February to Early May, 2003 : 2nd Half of the Dry Season at 6 Sites; Entire Dry Season monitoring at 1 site Nov 2003 - Present Preliminary Analysis Based on Level 1.5 Data: Awaiting Final Calibration for More Complete Analysis (4 sites have final level 2.0 data) Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3494
Chulalongkorn University, Bangkok Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3495
Phimai, Thailand site: Left to right- Mr. Khun Kamol (Site Manager); Tom Eck (AERONET); Dr. Jariya Boonjawat (Thailand coordinator of AERONET) Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3496
Project Atmospheric Brown Cloud ABC Observatories Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3497
SE Asia AERONET Sites: February-May 2003 Except Mukdahan - started in Nov 03 Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3498
AERONET Web-Site Composite TERRA-MODIS Image on MAR 11 of 2004 TERRA-MODIS Granule Overpass Times: 0350, 0345 UTC AOD (500 nm) Bangkok - 0.88 Phimai -0.60 Mukdahan - 0.95 Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3499
Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3500
April 7, 2003; SeaWiFS image - Smoke and pollution covers a large portion of the SE Asia region and advecting out over the South China Sea Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3501
4 Sites in Thailand Daily Ave. AOT Feb 16 - May 7, 2003 Level 1.5 Preliminary Cloud Screened Aerosol Optical Depth (500 nm) 1.6 1.4 1.2 1.0 0.8 0.6 0.4 Om Koi Phimai Hua Hin Chula Om Koi - webs data filtered Phimai - 2 cloudy days removed The first half of the monitoring period Feb 16 - Mar 21 (until Day 80) showed relatively low AOD in NW Thailand at the Om Koi site (1120 m elev) on mountain ridge top, and the highest AOD at the Phimai site. After Mar 21, the AOD was relatively high at all sites as large amounts of biomass burning smoke affected parts of the region. 0.2 0.0 40 60 80 100 120 Day of Year - 2003 Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3502
Aerosol Optical Depth (500 nm) 0.80 0.60 0.40 0.20 Monthly Average AOD (500 nm) Dry Season (2nd half: Feb-May) Cloud Screened PhiMai, TH Bangkok, TH Om Koi, TH Hua Hin, TH Bac Giang, VN Bac Lieu, VN Angstrom Exponent (440-870 nm) Monthly Average Angstrom Exponent Dry Season (2nd half: Feb-May) Cloud Screened 1.80 1.60 1.40 1.20 1.00 0.80 PhiMai, TH Bangkok, TH Om Koi, TH Hua Hin, TH Bac Giang, VN Bac Lieu, VN 0.00 2 3 4 5 0.60 2 3 4 5 Month Month Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3503
AERONET-MODIS Comparison of AOD retrievals Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3504
MODIS Retrievals - SE Asia April and May 2003 Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3505
0.20 Phimai, Thailand Feb - May, 2003 14 Almucantars/ AOD bin; AOD(440)>0.4 Level 2.0 Final Cal. & Cloud Screening 0.96 Phimai, Thailand Feb - May, 2003 14 Almucantars/ AOD bin; AOD(440)>0.4 Level 2.0 Final Cal. & Cloud Screening dv/ d (ln r) [ µm 3 /µm 2 ] 0.15 0.10 0.05 0.00 0.45 0.52 0.66 0.83 0.97 1.22 0.1 1 10 Radius (µm) Single Scattering Albedo 0.94 0.92 0.90 AOD 440 nm 0.45 0.88 0.52 0.66 0.83 0.97 1.22 0.86 400 500 600 700 800 900 1000 1100 Wavelength (nm) Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3506
dv/ d (ln r) [ µm 3 /µm 2 ] Comparison of SE Asian Aerosol Size Distributions for AOD (440 nm) ~ 0.70 0.14 0.12 0.10 0.08 0.06 0.04 0.02 0.00 Om Koi - 0.68 Bangkok - 0.70 PhiMai - 0.66 Hua Hin - 0.72 Bac Giang - 0.67 0.1 1 10 Radius (µm) Single Scattering Albedo Southeast Asia AERONET Sites - 2003 Dry Season Single Scattering Albedo Comparison - AOD(440)>0.4 All Cloud Screened Observations 0.93 0.92 0.91 0.90 0.89 0.88 0.87 0.86 Om Koi Bangkok PhiMai Hua Hin Bac Giang 0.85 400 500 600 700 800 900 1000 1100 Wavelength (nm) Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3507
Imaginary Refactive Index Southeast Asia AERONET Sites - 2003 Dry Season Imaginary Refractive Index Comparison - AOD(440)>0.4 All Cloud Screened Observations 0.016 0.014 0.012 0.010 0.008 0.006 Om Koi Bangkok Phimai Hua Hin Bac Giang 0.004 400 500 600 700 800 900 1000 1100 Wavelength (nm) Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3508
Entire Dry Season Monitoring at Mukdahan, Thailand Aerosol Optical Depth 2.50 2.00 1.50 1.00 0.50 Mukdahan, Thailand Dry Season Nov 2003 - April 2004 Daily Average AOD 380 nm Ave.=0.76 501 nm Ave.=0.56 870 nm Ave.=0.24 Angstrom Exponent (440/870 nm) 2.00 1.50 1.00 Mukdahan, Thailand Dry Season Nov 2003 - April 2004 Daily Average Angstrom Exponent WEXP 440/870 : Ave. = 1.45 0.00 Nov/1/03 Dec/1/03 Dec/31/03 Jan/31/04 Mar/1/04 Mar/31/04 May/1/04 0.50 Nov/1/03 Dec/1/03 Dec/31/03 Jan/31/04 Mar/1/04 Mar/31/04 May/1/04 Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3509
2.50 2.00 380 nm Ave.=0.76 501 nm Ave.=0.56 870 nm Ave.=0.24 Mukdahan, Thailand Dry Season Nov 2003 - April 2004 Daily Average AOD Aerosol Optical Depth 1.50 1.00 0.50 0.00 Nov/1/03 Dec/1/03 Dec/31/03 Jan/31/04 Mar/1/04 Mar/31/04 May/1/04 Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3510
Dry Season Trends in Single Scattering Albedo - Mukdahan Preliminary - Level 1.5 Data Single Scattering Albedo 1.00 0.95 0.90 0.85 0.80 Nov/16/03 Mukdahan, Thailand Dry Season Nov 2003 - April 2004 AOD(440 nm)>0.4; SZA > 45 deg. 440 nm 670 nm 870 nm Dec/21/03 Jan/25/04 Feb/29/04 Level 1.5 data Apr/4/04 May/9/04 Fine Mode Radius (µm) 0.24 0.22 0.20 0.18 0.16 0.14 0.12 0.10 Nov/16/03 Mukdahan, Thailand Dry Season Nov 2003 - April 2004 AOD(440 nm)>0.4; SZA > 45 deg. Dec/21/03 Rv(fine) Jan/25/04 Feb/29/04 Apr/4/04 May/9/04 Refractive Index (Imaginary) 0.025 0.020 0.015 0.010 0.005 0.000 Nov/16/03 Mukdahan, Thailand Dry Season Nov 2003 - April 2004 AOD(440 nm)>0.4; SZA > 45 deg. 440 nm 670 nm 870 nm Dec/21/03 Jan/25/04 Feb/29/04 Apr/4/04 May/9/04 Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3511
Comparison of Biomass Burning Regions - Size Distributions for AOD (440 nm) ~ 0.70 0.12 0.95 Comparison of Thailand Biomass Burning SSA versus Other Biomass Burning Regions dv/ d (ln r) [ µm 3 /µm 2 ] 0.10 0.08 0.06 0.04 0.02 0.00 Om Koi -1.81 Alpha Amazonian Forest Boreal Forest South American Cerrado African Savanna 0.1 1 10 Radius (µm) Single Scattering Albedo 0.90 0.85 0.80 Om Koi, Thailand Amazonia Boreal Forest S. American Cerrado African Savanna 0.75 400 500 600 700 800 900 1000 1100 Wavelength(nm) Amazon, Boreal, Cerrado, and Savanna data from Dubovik et al. [2002] Table 1. Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3512
Urban AERONET sites - Comparison dv/ d (ln r) [ µm 3 /µm 2 ] 0.14 0.12 0.10 0.08 0.06 0.04 0.02 0.00 Comparison of Urban Areas - Size Distributions for AOD (440 nm) ~ 0.70 Bangkok Beijing Washington DC (GSFC) Paris (Creteil) Mexico City 0.1 1 10 Radius (um) Single Scattering Albedo 1.00 0.95 0.90 0.85 Comparison of 'Urban' Single Scattering Albedo Average of all retrievals with AOD(440)>0.4 Bangkok Beijing Washington DC (GSFC) Paris (Creteil) Mexico City 0.80 400 500 600 700 800 900 1000 1100 Wavelength(nm) Washington, Paris, and Mexico City data from Dubovik et al. [2002] Table 1. Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3513
February 25, 2003 - High AOD (1.12 at 500 nm) at Phimai ; 8-Day Back Trajectory suggests transport of both pollution from industrial area SE of Bangkok and possibly also smoke and pollution from SW Cambodia and Viet Nam Average Angstrom Exp (440-870 nm) = 1.56 on Feb 25 at Phimai, Thailand SSA = ~0.94-0.92; Rv fine = ~0.17 µm Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3514
April 15, 2003 - High AOD (1.25 at 500 nm) at Om Koi ; 8-Day Back Trajectory suggests transport of both smoke and pollution from Burma, the Bay of Bengal, India and Pakistan Average Angstrom Exp (440-870 nm) = 1.55 on Apr 15 at Om Koi SSA = ~0.89 spectrally flat; Rv fine = ~0.15 µm Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3515
Kanpur, India Monthly Ave. Aerosol Optical Depth (500 nm) Years 2001 & 2002 1.00 1.40 Kanpur, India Monthly Ave. Angstrom Exponent Years 2001 & 2002 0.80 0.60 0.40 0.20 1.20 1.00 0.80 0.60 0.40 0.20 0.00 0.00 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Year JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Year Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3516 Aerosol Optical Depth (500 nm) Angstrom Exponent (440-870 nm)
May 5, 2003 - AOD ~0.2 at 500 nm at Om Koi; 8-Day Back Trajectory suggests transport of mixed fine and coarse mode aerosol from India Average Angstrom Exp (440-870 nm) = 1.15 on May 5, 2003 at Om Koi Rv fine = ~0.15 µm Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3517
June 1, 2003 - High AOD (~1.50 at 500 nm) at Bac Giang; 5-Day Back Trajectory suggests transport of fine mode aerosol from China SSA = ~0.96 spectrally flat; Rv fine = ~0.25-0.30 µm Average Angstrom Exp (440-870 nm) = 1.25 on Apr 15 at Bac Giang, Viet Nam Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3518
SUMMARY AND CONCLUSIONS Preliminary data suggest that during the 2nd half of the dry season the aerosol is quite strongly absorbing in both urban and rural sites in SE Asia (ω 0550 ~ 0.895-0.915) Aerosol size distributions are dominated by fine mode particles (radius < 0.6 micron) with very consistent size of fine particles at all sites (r v ~ 0.15-0.16 µm at τ a440 = 0.7) Data from Phimai suggest a dynamic aerosol model with particle size increasing as optical depth increases, and ω 0 also increasing as optical depth increases Mukdahan data (level 1.5) suggest a dry season decrease in Single scattering albedo from Nov - Apr with coincident decrease in fine mode particle size and increase in REF imag Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3519
Biomass-burning Aerosols in South East-Asia: Smoke Impact Assessment (BASE-ASIA, US Participation) Si-Chee Tsay, N. C. Hsu, Q. Ji, M. D. King, G. Molnar NASA Goddard Space Flight Center, Greenbelt, Maryland B. Huebert University of Hawaii, Honolulu, Hawaii L. Marufu, R. R. Dickerson and J. Stehr University of Maryland, College Park, Maryland D. Savoie University of Miami, Miami, Florida W.-Y. Sun and K. J. Yang Purdue University, West Lafayette, Indiana NASA/GSFC Collaborators: K.-M. W. Lau, B. Holben, M. Jhabvala, Y. Kaufman, P. K. Shu, A. Thompson, C. J. Tucker Opt. Pur. y Apl., Vol. 37, núm. 3, 2004 Autor: T.F. Eck et alt. 3520