Remote sensing from POLDER/PARASOL Earth polar- orbiting satellite: enhanced Surface/Aerosol...

Remote sensing from POLDER/PARASOL Earth polar-

orbiting satellite: enhanced Surface/Aerosol properties retrieval

P. Litvinov, O. Dubovik, T. Lapyonok, F. Ducos, D. Tanre

Laboratoire d'Optique Atmosphérique, CNRS, Universite Lille-1, FRANCE

Helsinki, August 19-21, 2013

Advanced retrieval algorithm

Multi-spectral, multi-angle I, Q, U

measurements

Aerosol model Surface reflection model

Enhanced retrieval of Aerosol/Surface properties

AOD, Re(m), Im(m), Size distribution, fraction of spherical particles, surface parameters etc.

Enhanced space-borne Aerosol/Surface retrieval

Reflection matrix for coupled atmosphere-surface system


I 0v

v 0

0

exp , expcos cosaer mol aer mol

v

t t

Aerosol and surface properties should be retrieved simultaneously!

0 0cos

““independentindependent”” POLDER/PARASOL POLDER/PARASOL

measurements :measurements :

VIEWS: N 16: (800 ≤ ≤ 1800)

INTENSITY (I): Nt6 (for aerosol): (0.44, 0.49, 0.56, 0.67, 0.865, 1.02 m)

Nt (for gas absorption): (0.763, 0.765, 0.910 m)

POLARIZATION (Q, U): NP3: (0.49, 0.67, 0.865 m)

SINGLE OBSERVATION:

NtNP

×N= (6+3)×16= 144

a lot !!! – as much as AERONET


PARASOL daily coverage image, March 3, 2013


Swath: about 1600 km cross-track Global coverage: every 2 days 1 pixel spatial resolution: 5.3km × 6.2km

New POLDER/PARASOL algorithm (GRASP) ((Dubovik et al, AMT, 2011))

• The new algorithm uses complete set of PARASOL angular measurements in all spectral bands including both radiance and linear polarization measurements.

• Continuous space of aerosol and surface properties is used.

• The algorithm is based on statistically optimized fitting.

The core of the new PARASOL algorithm is based on the same concept as AERONET aerosol retrieval (O. Dubovik and M. King, 2000; O. Dubovik, 2004; O. Dubovik et al, 2006).


The concept of the GRASP algorithm

Two scenarios of retrieval (Dubovik et al., AMT, 2011):

-Conventional: single-pixel retrieval (each single pixel is inverted independently)

-New concept: multiple-pixel retrieval (group of pixels are inverted simultaneously)

Bern, July 15-19, 2013

Aerosol model


retrieved

C + (1-C)

Aerosol model is the same as in AERONET retrieval (Mixing of particle shapes (Dubovik et al., 2006))

Surface reflection model


• Semi-empirical models for surface total reflectance description:- RPV model (Rahman et al., (1993))- Ross-Li (Ross, (1981); Li, X., Strahler (1992))- Ross-Roujean model (Roujean et al., (1992))

• Semi-empirical models for surface polarized reflectance description:- Nadal-Breon model (Nadal and Bréon, (1999))- Maignan model (Maignan et al., (2009))- Fresnel facet model for Gaussian surfaces (Litvinov et al., 2011)

• Physically based models for reflection matrix for surfaces:- Cox-Munk model (for aerosol retrieval over ocean)- Physical models for land surface reflection matrix

(Litvinov et al., 2012)

Bern, July 15-19, 2013 10

Perfect retrieval of synthetic measurements!!!

Comparison with AERONET

Bern, July 15-19, 2013 11

Banizoumbou

Mongu

Kanpur

Banizoumbou: January, February, 2008 Surface: Grassland. Aerosol: Coarse mode is dominated.

Mongu: August, September, 2008 Surface: Savanna. Aerosol: Fine mode is dominated.

Beijing: April, December, 2008 Surface: Urban. Aerosol: Fine and Coarse modes.

Kanpur: October-December, 2008 Surface: Urban. Aerosol: Fine and Coarse modes.

The IGBP (International Geosphere Biosphere Programme) land type specification was used

Beiging

Bern, July 15-19, 2013

POLDER/AERONET. AOD.

St.Dev.=0.160St.Dev.=0.128

POLDER/AERONET.Angstrom Exponent.

Bern, July 15-19, 2013

St.Dev.=0.262

POLDER/AERONET. SSA.

Bern, July 15-19, 2013

St.Dev.=0.045

St.Dev.=0.051

Bern, July 15-19, 2013 15

DHR retrieval, Banizoumbou, 2007, 2008.

Black curves and markers: DHR in 2007.

Color curves and markers: DHR in 2008

There are possibilities for surface climatology and surface changes monitoring!!!

Surface modeling effect on aerosol retrieval.AOD retrieval over Banizoumbou, Mongu.

Bern, July 15-19, 2013 16

Surface modeling effect on aerosol retrieval.SSA retrieval over Banizoumbou, Mongu

Bern, July 15-19, 2013 17Physical models are required to increase accuracy of aerosol retrieval.

I,Q,U retrieval vs I-retrieval: total reflectance fits


I,Q,U retrieval vs I-retrieval: polarized reflectance fits


I,Q,U retrieval vs I-retrieval retrieval: AOD (Banizoumbou)


I,Q,UI-retrieval

I,Q,U retrieval vs I-retrieval retrieval: SSA (Banizoumbou)


I,Q,UI-retrieval

Multi-pixel vs Single pixel retrieval: AOD (Banizoumbou)


Multi-pixel Single pixel

Multi-pixel vs Single pixel retrieval: SSA (Banizoumbou)


Multi-pixel Single pixel

Regional maps (1800 x 1800 km).Banizoumbou, AOD 670 nm


Strong spatial and temporal variation of AOD

Regional maps (1800 x 1800 km).Banizoumbou, SSA 670 nm


Essential temporal variation of SSA

Daily variation of AOD and SSA at 670 nm. Banizoumbou (Jan., Febr. 2008).


21.02.2008

23.02.2008

Regional maps (1800 x 1800 km).Banizoumbou, SALB 670 nm

Bern, July 15-19, 2013 Surface is very stable for Jan. and Febr.!

Regional maps (1800 x 1800 km).Mongu, SSA 670 nm


Small SSA correspond to biomass burning

NASA Global Fire Maps28.08.2008 – 06.09.2008

(detected by MODIS)


Advanced retrieval Algorithm

- LOA (Lille, France) GRASP algorithm (O.Dubovik et al, AMT, 2011).- SRON (Utrecht, The Netherlands) algorithm (O.Hasekamp et al, JGR, 2012)

Multi-spectral, multi-angle I, Q, U

measurementsPARASOL will end up in September 2013. There may be 7 years gap in polarimetric space-borne measurements!!!

Aerosol modelAt present time the mixture of spherical and spheroidal particles is the most comprehensive existent aerosol model (Dubovik et al., 2006).

Surface reflection model- Physical models are required to increase accuracy of aerosol retrieval over land. - Physical models provide possibilities for surface characterization (Litvinov et al., 2012).

Enhanced retrieval of Aerosol/Surface

properties

Resume (space-borne Aerosol/Surface retrieval)


• Multi-spectral, multi-angle I, Q, U space-borne measurements:- PARASOL will end up in September 2013! - 3MI will be launched in 2020 (?).- Ukrainian version of GISS NASA APS (Aerosol Polarimetry Sensor) instrument may be launched in 3 years (the possibility to set up Dutch SPEX instrument on the same satellite is being discussed now).There may be 7 years gap in polarimetric space-borne measurements!!!

• Advanced retrieval algorithm:- LOA (Lille, France) GRASP algorithm (O.Dubovik et al, AMT, 2011)- SRON (Utrecht, The Netherlands) algorithm (O.Hasekamp et al, JGR, 2012)


• Aerosol model:At present time the mixture of spherical and spheroidal particles is the most comprehensive existent aerosol model (Dubovik et al., 2006).

• Surface reflection model- Physical models are required to increase accuracy of aerosol retrieval over land (Litvinov et al., 2011; Litvinov et al., 2012). - Physical models provide possibilities for surface characterization (Litvinov et al., 2012).

Remote sensing from POLDER/PARASOL Earth polar- orbiting satellite: enhanced Surface/Aerosol...

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