aerosol optical properties in southeast asia from aeronet observations t.f. eck 1, b.n. holben 1, j....
TRANSCRIPT
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
1NASA / GSFC, Greenbelt, MD, USA2Chulalongkorn University, Bangkok, Thailand
3Vietnam National Center for Natural Science and Technology, Hanoi, Vietnam4NRL, Monterey, CA, USA
AERONET-An Internationally Federated Network
Characterization of aerosol optical propertiesValidation of Satellite Aerosol RetrievalsNear real-time acquisition; long term measurementsHomepage access http://aeronet.gsfc.nasa.gov
AERONET Monitoring of Aerosol Optical Properties in SE Asia
• 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
•First Year of AERONET Monitoring in Thailand and Vietnam, with Plans for Continuing Monitoring
• Preliminary Analysis Based on Level 1.5 Data: Awaiting Final Calibration for More Complete Analysis (4 sites have final level 2.0 data)
Chulalongkorn University, Bangkok
Phimai, Thailand site: Left to right- Mr. Khun Kamol (Site Manager); Tom Eck (AERONET); Dr. Jariya Boonjawat (Thailand coordinator of AERONET)
Project Atmospheric Brown Cloud
ABC Observatories
SE Asia AERONET Sites: February-May 2003
Except Mukdahan - started in Nov 03
Composite TERRA-MODIS Image on MAR 11 of 2004TERRA-MODIS Granule Overpass Times:
0350, 0345 UTC AERONET Web-Site
AOD (500 nm)
Bangkok - 0.88
Phimai -0.60
Mukdahan - 0.95
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
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
40 60 80 100 120
4 Sites in Thailand Daily Ave. AOT Feb 16 - May 7, 2003Level 1.5 Preliminary Cloud Screened
Om KoiPhimai Hua HinChula
Aer
osol
Op
tica
l D
epth
(50
0 n
m)
Day of Year - 2003
Om Koi - webs data filteredPhimai - 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.
0.00
0.20
0.40
0.60
0.80
2 3 4 5
Monthly Average AOD (500 nm) Dry Season (2nd half: Feb-May) Cloud Screened
PhiMai, THBangkok, THOm Koi, THHua Hin, THBac Giang, VNBac Lieu, VN
Aer
osol
Opt
ical
Dep
th (
500
nm
)
Month
0.60
0.80
1.00
1.20
1.40
1.60
1.80
2 3 4 5
Monthly Average Angstrom Exponent Dry Season (2nd half: Feb-May) Cloud Screened
PhiMai, THBangkok, THOm Koi, THHua Hin, THBac Giang, VNBac Lieu, VN
An
gstr
om E
xpon
ent
(440
- 8
70 n
m)
Month
AERONET-MODIS Comparison of AOD retrievals
MODIS Retrievals - SE Asia April and May 2003
0.00
0.05
0.10
0.15
0.20
0.1 1 10
Phimai, Thailand Feb - May, 200314 Almucantars/ AOD bin; AOD(440)>0.4
Level 2.0 Final Cal. & Cloud Screening
0.450.520.660.830.971.22
dV
/ d
(ln
r)
[ m
3/
m2]
Radius (m)
0.86
0.88
0.90
0.92
0.94
0.96
400 500 600 700 800 900 1000 1100
Phimai, Thailand Feb - May, 200314 Almucantars/ AOD bin; AOD(440)>0.4
Level 2.0 Final Cal. & Cloud Screening
0.450.520.660.830.971.22
Sin
gle
Sca
tter
ing
Alb
edo
Wavelength (nm)
AOD 440 nm
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.1 1 10
Comparison of SE Asian Aerosol Size Distributionsfor AOD (440 nm) ~ 0.70
Om Koi - 0.68Bangkok - 0.70PhiMai - 0.66Hua Hin - 0.72Bac Giang - 0.67
dV
/ d (
ln r
) [ m
3/
m2]
Radius (m)
0.85
0.86
0.87
0.88
0.89
0.90
0.91
0.92
0.93
400 500 600 700 800 900 1000 1100
Southeast Asia AERONET Sites - 2003 Dry SeasonSingle Scattering Albedo Comparison - AOD(440)>0.4
All Cloud Screened Observations
Om KoiBangkokPhiMaiHua HinBac Giang
Sin
gle
Scat
teri
ng
Alb
edo
Wavelength (nm)
0.004
0.006
0.008
0.010
0.012
0.014
0.016
400 500 600 700 800 900 1000 1100
Southeast Asia AERONET Sites - 2003 Dry SeasonImaginary Refractive Index Comparison - AOD(440)>0.4
All Cloud Screened Observations
Om KoiBangkokPhimaiHua HinBac Giang
Imag
inar
y R
efac
tive
In
dex
Wavelength (nm)
0.00
0.50
1.00
1.50
2.00
2.50
Nov
/1/0
3
Dec
/1/0
3
Dec
/31/
03
Jan
/31/
04
Mar
/1/0
4
Mar
/31/
04
May
/1/0
4
Mukdahan, Thailand Dry Season Nov 2003 - April 2004
Daily Average AOD
380 nm Ave.=0.76501 nm Ave.=0.56870 nm Ave.=0.24
Aer
osol
Op
tica
l D
epth
0.50
1.00
1.50
2.00
Nov
/1/0
3
Dec
/1/0
3
Dec
/31/
03
Jan
/31/
04
Mar
/1/0
4
Mar
/31/
04
May
/1/0
4
Mukdahan, Thailand Dry Season Nov 2003 - April 2004
Daily Average Angstrom Exponent
WEXP 440/870 : Ave. = 1.45
An
gstr
om E
xpon
ent
(440
/870
nm
)
Entire Dry Season Monitoring at Mukdahan, Thailand
0.00
0.50
1.00
1.50
2.00
2.50
Nov
/1/0
3
Dec
/1/0
3
Dec
/31/
03
Jan
/31/
04
Mar
/1/0
4
Mar
/31/
04
May
/1/0
4
Mukdahan, Thailand Dry Season Nov 2003 - April 2004
Daily Average AOD
380 nm Ave.=0.76501 nm Ave.=0.56870 nm Ave.=0.24
Aer
osol
Op
tica
l D
epth
0.80
0.85
0.90
0.95
1.00
Nov
/16/
03
Dec
/21/
03
Jan
/25/
04
Feb
/29/
04
Ap
r/4/
04
May
/9/0
4
Mukdahan, Thailand Dry Season Nov 2003 - April 2004AOD(440 nm)>0.4; SZA > 45 deg.
440 nm670 nm870 nm
Sin
gle
Scat
teri
ng
Alb
edo
Level 1.5 data
0.10
0.12
0.14
0.16
0.18
0.20
0.22
0.24
Nov
/16/
03
Dec
/21/
03
Jan
/25/
04
Feb
/29/
04
Ap
r/4/
04
May
/9/0
4
Mukdahan, Thailand Dry Season Nov 2003 - April 2004AOD(440 nm)>0.4; SZA > 45 deg.
Rv(fine)
Fin
e M
ode
Rad
ius
(m
)
0.000
0.005
0.010
0.015
0.020
0.025
Nov
/16/
03
Dec
/21/
03
Jan
/25/
04
Feb
/29/
04
Ap
r/4/
04
May
/9/0
4
Mukdahan, Thailand Dry Season Nov 2003 - April 2004AOD(440 nm)>0.4; SZA > 45 deg.
440 nm670 nm870 nm
Ref
ract
ive
Ind
ex (
Imag
inar
y)
Dry Season Trends in Single Scattering Albedo - Mukdahan
Preliminary - Level 1.5 Data
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.1 1 10
Comparison of Biomass Burning Regions - Size Distributionsfor AOD (440 nm) ~ 0.70
Om Koi -1.81 AlphaAmazonian ForestBoreal ForestSouth American CerradoAfrican Savanna
dV
/ d
(ln
r)
[ m
3/
m2]
Radius (m)
0.75
0.80
0.85
0.90
0.95
400 500 600 700 800 900 1000 1100
Comparison of Thailand Biomass Burning SSAversus Other Biomass Burning Regions
Om Koi, ThailandAmazoniaBoreal ForestS. American CerradoAfrican Savanna
Sin
gle
Sca
tter
ing
Alb
edo
Wavelength(nm)
Amazon, Boreal, Cerrado, and Savanna data from Dubovik et al. [2002] Table 1.
Washington, Paris, and Mexico City data from Dubovik et al. [2002] Table 1.
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.1 1 10
Comparison of Urban Areas - Size Distributionsfor AOD (440 nm) ~ 0.70
BangkokBeijingWashington DC (GSFC)Paris (Creteil)Mexico City
dV
/ d
(ln
r)
[ m
3/
m2]
Radius (um)
0.80
0.85
0.90
0.95
1.00
400 500 600 700 800 900 1000 1100
Comparison of 'Urban' Single Scattering AlbedoAverage of all retrievals with AOD(440)>0.4
BangkokBeijingWashington DC (GSFC)Paris (Creteil)Mexico City
Sin
gle
Sca
tter
ing
Alb
edo
Wavelength(nm)
Urban AERONET sites - Comparison
Average Angstrom Exp (440-870 nm) = 1.56 on Feb 25 at Phimai, Thailand
SSA = ~0.94 - 0.92; Rvfine = ~0.17 m
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
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; Rvfine = ~0.15 m
0.00
0.20
0.40
0.60
0.80
1.00
JA
N
FE
B
MA
R
AP
R
MA
Y
JU
N
JU
L
AU
G
SE
P
OC
T
NO
V
DE
C
Ye
ar
Kanpur, India Monthly Ave. Aerosol Optical Depth (500 nm)Years 2001 & 2002
Aer
osol
Opt
ical
Dep
th (
500
nm
)
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
JAN
FE
B
MA
R
AP
R
MA
Y
JUN
JUL
AU
G
SE
P
OC
T
NO
V
DE
C
Yea
r
Kanpur, India Monthly Ave. Angstrom ExponentYears 2001 & 2002
An
gstr
om E
xpon
ent
(440
-870
nm
)
Average Angstrom Exp (440-870 nm) = 1.15 on May 5, 2003 at Om Koi
Rvfine = ~0.15 m
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
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; Rvfine = ~0.25 - 0.30 m
Average Angstrom Exp (440-870 nm) = 1.25 on Apr 15 at Bac Giang, Viet Nam
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 (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 (rv ~ 0.15 - 0.16 m at a440 = 0.7)
•Data from Phimai suggest a dynamic aerosol model with particle size increasing as optical depth increases, and 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 REFimag
Biomass-burning Aerosols in South East-Asia: Smoke Impact Assessment (BASE-ASIA, US
Participation)
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, HawaiiL. Marufu, R. R. Dickerson and J. Stehr
University of Maryland, College Park, MarylandD. Savoie
University of Miami, Miami, FloridaW.-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
3 April 2001Terra/MODIS True ColorRayleigh scattering removed
BASE-ASIA
• Research Goals: aerosol-cloud interactions, impacts on cloud lifetime and precipitation.
• Approach: synergy of measurements from satellites, remote-sensing & in-situ aircraft, and ground-based network, and regional modeling.
smoke
cloud
interaction
Pre-monsoon season in Southeast Asia: A Terra MODIS view showing distinct large-scale smoke, cloud & interaction regions.24 March 2004
SeaWiFS True Color
Pochanart et al., JGR, 2003
0.0
0.5
1.0
1.5
2.0
40 60 80 100 120
Phimai, Thailand Elevation 220 mDaily Ave. AOT Feb 17 - May 7, 2003Level 1.5 Preliminary Cloud Screened
AOT 380 : 0.79AOT 500 : 0.56AOT 868 : 0.23
Aer
osol
Op
tica
l D
epth
Day of Year - 2003
0.6
0.8
1.0
1.2
1.4
1.6
1.8
40 60 80 100 120
Phimai, Thailand Elevation 220 mDaily Ave. Alpha Feb 17 - May 7, 2003Level 1.5 Preliminary Cloud Screened
An
gstr
om E
xpon
ent
(440
-870
)
Day of Year - 2003
Angstrom Exponent was typically >1.4 : Therefore Fine mode particles (radius <0.6 micron) dominated
SE Asia AERONET Sites: February-May 2003
April 8, 2003 - Numerous fires in India, Burma, and Laos and NW Thailand -
Om Koi: AOD(500nm)=0.45 at Aqua (MODIS) Satellite Overpass time