New Developments in AERONET aerosol retrievals

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Outlines: Outlines: Improving operational retrieval software Improving operational retrieval software Aerosol particle non-sphericity Aerosol particle non-sphericity Inversion of combined AERONET/satellite Inversion of combined AERONET/satellite observations observations Oleg Dubovik (Code 614.4) New Developments in AERONET aerosol retrievals

description

Oleg Dubovik (Code 614.4 ). New Developments in AERONET aerosol retrievals. Outlines: Improving operational retrieval software Aerosol particle non-sphericity Inversion of combined AERONET/satellite observations. INPUT of Forward Model. Aerosol characterization form AERONET retrievals. - PowerPoint PPT Presentation

Transcript of New Developments in AERONET aerosol retrievals

Page 1: New Developments in  AERONET aerosol retrievals

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

Page 2: 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

Page 3: New Developments in  AERONET aerosol 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

Page 4: New Developments in  AERONET aerosol retrievals

AERONETAERONET model of aerosol model of aerosolspherical:spherical:

Randomly orientedRandomly orientedspheroids :spheroids :

(Mishchenko et al., 1997)(Mishchenko et al., 1997)

Page 5: New Developments in  AERONET aerosol retrievals

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)

Page 6: New Developments in  AERONET aerosol retrievals

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)

Page 7: New Developments in  AERONET aerosol retrievals

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

Page 8: New Developments in  AERONET aerosol retrievals

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

()

Page 9: New Developments in  AERONET aerosol retrievals

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

Page 10: New Developments in  AERONET aerosol retrievals

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

Page 11: New Developments in  AERONET aerosol retrievals

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

Page 12: New Developments in  AERONET aerosol retrievals

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

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Surface Albedo: Surface BRDF:

Comparisons of Surface Retrievals (with improved vertical profile)

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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

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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

Page 14: New Developments in  AERONET aerosol retrievals

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)

Page 15: New Developments in  AERONET aerosol retrievals

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