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Outlines:Outlines:
Improving operational retrieval softwareImproving operational retrieval software
Aerosol particle non-sphericityAerosol particle non-sphericity
Inversion of combined AERONET/satellite Inversion of combined AERONET/satellite observationsobservations
Oleg Dubovik (Code 614.4)
New Developments in AERONET aerosol retrievals
Particle Size Distribution:0.05 m ≤ R (22 bins) ≤ 15 m
Complex Refractive Index at = 0.44; 0.67; 0.87; 1.02 m
0.01
0.02
0.04
0.05
0.07
0.1 1 10
dV
/dln
R(
m3 /
m2)
Radius (m)0.00
0.01
0.10
Wavelength (m)0.44 0.67 0.87 1.02
Imarinary PartImaginary Part
1.35
1.40
1.45
1.50
1.55
1.60
Wavelength (m)0.44 0.67 0.87 1.02
Real Part
Smoke Desert Dust Maritime
Aerosol characterization form AERONET retrievals
AERONET Inversion 2
Flexibility and refinements of the algorithm: - any number of spectral channel (from 0.34 to 1.64 m) - any measurements geometry (almucantar, principle plane, etc.) - dynamic error estimates for all retrieval products - improved assumptions about surface reflectance (Moody et al. 2005) - utilizing measurements of polarization (not operational yet)
New products from retrievals: - particle non-sphericity - direct aerosol radiative forcing computations - degree of polarization, phase function, etc. New concepts in the retrieval:New concepts in the retrieval: - non-spherical aerosols - using co-incident satellite observations in the retrievals
AERONETAERONET model of aerosol model of aerosolspherical:spherical:
Randomly orientedRandomly orientedspheroids :spheroids :
(Mishchenko et al., 1997)(Mishchenko et al., 1997)
spheroidspheroid kernels data basekernels data basefor for operational modeling !!!operational modeling !!!
Basic Model by Mishchenko et al. Basic Model by Mishchenko et al. 1997:1997:randomly oriented homogeneous spheroids () - size independent shape distribution
,F11,...,F44 K ip ...;n;k i;p p V ri
K - pre-computed kernel matrices:Input: n and k
Input: p (Np =11), V(ri) (Ni =22 -26)
Output: (), 0(),
F11(), F12(),F22(),
F33(),F34(),F44()
Time:Time: < < one sec.one sec.Accuracy:Accuracy: < < 1-3 %1-3 %
Range of applicability:Range of applicability:0.15 ≤ 20.15 ≤ 2r/r/≤ ≤ 280 280 (26 bins)(26 bins)
0.4 ≤ 0.4 ≤ ≤ 2.4 ≤ 2.4 (11 bins)(11 bins)1.33 ≤ n ≤ 1.6 1.33 ≤ n ≤ 1.6
0.0005 ≤ k ≤ 0.50.0005 ≤ k ≤ 0.50.1
1
10
100
0 40 80 120 160
Phase Functions (0.67 m)
Spheres
Spheroids - 1()
Spheroids - 1()
Scattring Angle (degree)
NEW CONCEPT - retrieving degree of non-sphericity as an additional parameter
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
1 2
Desert Dust (Saudi Arabia)
Maritime (Lanaii/Hawai)
Biomas Burning (Zambia)
dn
(')
/dln
Aspect Ratiospheres
Non-spheres
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0.1 1 10
Desert Dust (Saudi Arabia)
Maritime (Lanaii/Hawai)
Biomas Burning (Zambia)
dV
(r)/
dln
r (n
om
ali
zed
to m
axim
um
)
Radius (m)
Retrieved aspect ratio
The retrieval is possible for aerosols with pronounced coarse fraction, i. e. desert dust and maritime ( < ~ 1.2)
AERONET-MSP(multispectral polarization)
Spectral Percent linear Polarization hourly
Standard Products L(nm): 340, 380, 440,
500, 675, 870, 940, 1020, 1640
AERONET testing (Feb. to May 2006)
Operational products: June 2006 Dual filter wheel, top for polarizers
bottom for IAD filtersB.N. Holben
Sensitivity of polarization to particle shape
Coarse aerosol
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0 45 90 135 180
Spheres (rv = 2.0 m)
n = 1.33n = 1.4n = 1.45n = 1.5n = 1.55n = 1.6
Scattering Angle (degree)
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0 45 90 135 180
Spheroids (rv = 2.0 m)
n = 1.33n = 1.4n = 1.45n = 1.5n = 1.55n = 1.6
Scattering Angle (degree)
-P12
()/
P11
()
-P12
()/
P11
()
0.1
1
10
100
1000
104
0 20 40 60 80 100 120 140
Atm
osp
her
ic R
adia
ince
s in
Pri
nci
ple
Pla
ne
A
I()
0.44m
0.50m
0.67m
0.87m
1.02m
I()*10
I()*102
I()*103
I()*104
- measurements- spheroids- spheres
Scattering Angle (degree)
(spheroids)~ 5%; (spheres)~ 10% (spheroids) < 0.01; (spheres)~ 0.05
0
0.5
1
1.5
2
2.5
0 40 80 120 160
Der
gee
of
Lin
ear
Po
lari
zati
on
in
Pri
nci
ple
Pla
ne
A
P()
P() + 0.5
P() + 1.0
P() + 2.0
P() + 1.5
0.44m
0.50m
0.67m
0.87m
1.02m
Scattering Angle (degree)
spheroids) < 0.01; spheres)~ 0.05
0
0.05
0.1
0.15
0.2
0.1 1 10
dV
/dln
R (m
3/
m2)
Particle Radius (m)
(870/440)
= 0.26
(440) = 0.57
Simultaneous Inversion of intensity and Polarization measured in principle plane at
5 channels (0.44; 0.5; 067; 0.87; 1.02)
Maarco, August 8, 2004
Combining of observations:satellite, ground-based and aircraft
Retrieved:
AEROSOL:
- Size Distribution- Real Refractive Index- Absorption
- Vertical variability
CALIPSO
LIDAR
size
concentration
co
nc
en
tra
tio
na
ltit
ud
e
SURFACE :
- Albedo - Bi-directional reflectance
CALIPSO
LIDAR
Simultaneous fitting August 9, 2003(0.44) ~ 0.3
0.01
0.1
1
10
100
1000
104
0 20 40 60 80 100 120 140
Mongu, August 9 2003residual=1.75%
440 fit440 measurements670 fit670 measurements870 fit870 measurements1020 fit1020 measurements
An
gu
lar
Dis
trib
uti
on
of
Ra
dia
tio
n (
AE
RO
NE
T)
View Angle, degree
x101
x102
x103
x104
0
0.05
0.1
0.15
0.2
0.25
0.3
0.4 0.5 0.6 0.7 0.8 0.9 1 1.1
Mongu, August 9 2003residual=0.03%
fitmeasurements
An
gu
lar
Dis
trib
uti
on
of
Ra
dia
tio
n (
MO
DIS
)
Wavelength, m
AERONET
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
-80 -60 -40 -20 0 20 40 60 80
Mongu August 9 2003
MISR 440 fitMISR 440 measurementsMISR 670 fitMISR 670 measurementsMISR 870 fitMISR 870 measurementsMODIS 440 fitMODIS 440 measurementsMODIS 670 fitMODIS 670 measurementsMODIS 870 fitMODIS 870 measurements
An
gu
lar
Dis
trib
uti
on
of
Ra
dia
tio
n
View Angle, degree
MISR-MODIS
MODIS
Surface Albedo: Surface BRDF:
Comparisons of Surface Retrievals (with improved vertical profile)
0
0.1
0.2
0.3
0.4
-80 -60 -40 -20 0 20 40 60 80
MISR, August 9 2003POLDER, August 7 2003POLDER, August 10 2003
BR
F
View Angle, degree
MONGU
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.4 0.5 0.6 0.7 0.8 0.9
MISR, August 9 2003POLDER, August 7 2003POLDER, August 10 2003Assumed by AERONET
Su
rfac
e A
lbed
o
Wavelength, m
MONGU
Surface Effect on Retrievals of the fine mode aerosols (low aerosol loading)
POLDER: June 24, 2003(0.44) ~ 0.26 , SZA=470
1.35
1.4
1.45
1.5
1.55
1.6
0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2
Mongu, June 24, 2003
almucantor + POLDERalmucantor,surface albedo retrievedalmucantor,surface albedo assumed
Re
al P
art
of
Re
fra
cti
ve
Ind
ex
Wavelength (m)
0
0.01
0.02
0.03
0.04
0.05
0.06
0.1 1 10
Mongu, June 24, 2003
almucantor + POLDER,res=1.5%almucantor,surface albedo retrieved,res=1.56%almucantor,surface albedo assumed,res=1.47%
dV
/dln
R (
m3 /
m2 )
Particle Radius (m)
Version 2 operational retrievalVersion 2 operational retrieval
More More robustrobust, more , more accurateaccurate and and better characterizedbetter characterized results results
Utilize new types of measurements (Utilize new types of measurements (polarizationpolarization, , principle planeprinciple plane, etc), etc)
Provide new retrieval products: Provide new retrieval products: particle shape, particle shape,
forcingforcing, etc., etc.
Plans:Plans:
Using co-incident observations of MODIS, MISR and Using co-incident observations of MODIS, MISR and POLDER POLDER
Including Including Lidar information Lidar information into retrievals into retrievals