ceamanos_igarss.pdf

Xavier
Ceamanos,
S.
Douté1,
A.
Lyapus9n2,
J.
Fernando3
and
P.
Pinet3

1
Ins%tut
de
Planétologie
et
d’Astrophysique
de
Grenoble,
France

2
NASA
Goddard
Space
Flight
Center,
USA

3
IRAP,
Toulouse,
France

Aerosols
and
Atmospheric
Chemistry
III
–
July
29,
2011

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
xavier.ceamanos@obs.ujf-‐grenoble.fr
2

¡  Hyperspectral
remote
sensing
of
Mars

¡  Retrieval
of
atmospheric
opacity

¡  Retrieval
of
surface
reﬂectance

¡  Valida9on
on
the
Gusev
crater

¡  Conclusions
and
perspec9ves

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
3

remote
sensing
of
Mars

¡  Retrieval
of
atmospheric
opacity

¡  Retrieval
of
surface
reﬂectance

¡  Valida9on
on
the
Gusev
crater

and
perspec9ves

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
4

The
atmosphere
of
Mars

¡  Mars:

§  Polar
caps,
dust
storms,
H20

and
CO2
seasonal
cycles,
…

¡  Mariner
4
(1965)
-‐>
MRO
(2006)

¡  VNIR
imaging
spectroscopy

§  Goal:

▪  Monitoring
the
chemical

composi%on
and
the
physical

state
of
the
atmosphere
and
the

surface

§  OMEGA@MEX,
ESA,
2003

§  CRISM@MRO,
NASA,
2006

The
northern
ice
cap
of
Mars

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
5

¡  CRISM
(Compact
Reconnaissance
Imaging
Spectrometer
for
Mars)

§  18
m/pix,
0.4-‐3.9
μm,
6.5
nm/channel

§  Mul9-‐angle
observa9ons

▪  1
x
quasi-‐nadir
scan
at
18
m/pix

▪  10
x
oﬀ-‐nadir
scans
at
180
m/pix

1st
7th
11th

…
…

Atmosphere

Superposi9on
of
the
eleven

Surface
target
hyperspectral
images
corresponding

to
a
single
CRISM
observa9on

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
6

¡  CRISM
(Compact
Reconnaissance
Imaging
Spectrometer
for
Mars)

§  18
m/pix,
0.4-‐3.9
μm,
6.5
nm/channel

observa9ons

▪  1
x
quasi-‐nadir
scan
at
18
m/pix

▪  10
x
oﬀ-‐nadir
scans
at
180
m/pix

1st
7th
11th

…
…
11
km

Atmosphere

Superposi9on
of
the
eleven

Surface
target
hyperspectral
images
corresponding

to
a
single
CRISM
observa9on

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
7

¡  CRISM
(Compact
Reconnaissance
Imaging
Spectrometer
for
Mars)

§  18
m/pix,
0.4-‐3.9
μm,
6.5
nm/channel

observa9ons

▪  1
x
quasi-‐nadir
scan
at
18
m/pix

▪  10
x
oﬀ-‐nadir
scans
at
180
m/pix

1st
7th
11th

…
…
11
km

Atmosphere
-‐70º<VZA<70º

Superposi9on
of
the
eleven

Surface
target
hyperspectral
images
corresponding

to
a
single
CRISM
observa9on

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
8

¡  CRISM
(Compact
Reconnaissance
Imaging
Spectrometer
for
Mars)

§  18
m/pix,
0.4-‐3.9
μm,
6.5
nm/channel

observa9ons

▪  1
x
quasi-‐nadir
scan
at
18
m/pix

▪  10
x
oﬀ-‐nadir
scans
at
180
m/pix

Spectro-‐photometric
curve

Superposi9on
of
the
eleven

hyperspectral
images
corresponding

to
a
single
CRISM
observa9on

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
9

¡  CRISM
(Compact
Reconnaissance
Imaging
Spectrometer
for
Mars)

§  18
m/pix,
0.4-‐3.9
μm,
6.5
nm/channel

observa9ons

▪  1
x
quasi-‐nadir
scan
at
18
m/pix

▪  10
x
oﬀ-‐nadir
scans
at
180
m/pix

Photometric
curve

curve

Forward
scai.
Superposi9on
of
the
eleven

hyperspectral
images
corresponding

to
a
single
CRISM
observa9on

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
10

¡  CRISM
(Compact
Reconnaissance
Imaging
Spectrometer
for
Mars)

§  18
m/pix,
0.4-‐3.9
μm,
6.5
nm/channel

observa9ons

▪  1
x
quasi-‐nadir
scan
at
18
m/pix

▪  10
x
oﬀ-‐nadir
scans
at
180
m/pix

BRDF(θ0,θ,ϕ,λ)

Photometric
curve

curve

Forward
scai.
Superposi9on
of
the
eleven

hyperspectral
images
corresponding

to
a
single
CRISM
observa9on

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
11

¡  The
atmosphere
of
Mars

§  Very
faint
(6
mbar
at
ground)
but
signiﬁcant
opaci9es!

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
12

¡  The
atmosphere
of
Mars

§  Very
faint
(6
mbar
at
ground)
but
signiﬁcant
opaci9es!

ATMOSPHERIC
GASES

¡  95%
CO2
gas

¡ 

is
computed
by
RT
codes

NIR
atmospheric
CO2
absorp9on
bands

1
CO2 gas frt5089
0.8 frt50d0
Reference spectrum
Transmission

0.6

0.4

0.2

0
1000 1500 2000 2500 3000 3500 4000
Wavelength 100 200 300 400

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
13

¡  The
atmosphere
of
Mars

§  Very
faint
(6
mbar
at
ground)
but
signiﬁcant
opaci9es!

ATMOSPHERIC
GASES
DUST
AEROSOLS1

¡  95%
CO2
gas
¡  Op%cal
proper%es

¡ 

is
computed
by
RT
codes
¡  Cylindrical
par%cles
(rad.=1.4
μm,
ω0
=
0.94)

¡  Phase
func%on:

NIR
atmospheric
CO2
absorp9on
bands

1
CO2 gas frt5089
0.8 Strong
forward
frt50d0
scaiering
Reference spectrum
Transmission

0.6 proper9es

0.4

0.2
Mar9an
aerosol

0 phase
func9on

1000 1500 2000 2500 3000 3500 4000
100 Wolﬀ
e200 l.
2009]

Wavelength 1:
[ t
a 300 400

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
14

¡  The
atmosphere
of
Mars

§  Very
faint
(6
mbar
at
ground)
but
signiﬁcant
opaci9es!

ATMOSPHERIC
GASES
DUST
AEROSOLS1

¡  95%
CO2
gas
¡  Op%cal
proper%es

¡ 

is
computed
by
RT
codes
¡  Cylindrical
par%cles
(rad.=1.4
μm,
ω0
=
0.94)

¡  Phase
func%on:

1
NIR
atmospheric
CO2
absorp9on
bands
¡  Content
varies
with
9me!

CO2 gas frt5089
0.8 Strong
forward
frt50d0
scaiering
Reference spectrum
Transmission

0.6 proper9es

0.4

0.2
Mar9an
aerosol

0 phase
func9on

1000 1500 2000 2500 3000 3500 4000
100 Wolﬀ
e200 l.
2009]

Wavelength 1:
[ t
a 300 400

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
15

remote
sensing
of
Mars

¡  Retrieval
of
atmospheric
opacity

¡  Retrieval
of
surface
reﬂectance

¡  Valida9on
on
the
Gusev
crater

and
perspec9ves

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
16

¡  Retrieval
of
aerosol
op9cal
thickness
(AOT)

Mar%an
mineral
spectrum

¡  “β-‐method”1

§  β:
correla%on
between
the
AOT
and
the

intensity
of
the
CO2
absorp%on
band
at
2
μm

1:
[Douté
and
Ceamanos,
IEEE
WHISPERS
2010]

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
17

¡  Retrieval
of
aerosol
op9cal
thickness
(AOT)

Mar%an
mineral
spectrum

¡  “β-‐method”1

§  β:
correla%on
between
the
AOT
and
the

intensity
of
the
CO2
absorp%on
band
at
2
μm

§  Top-‐of-‐atmosphere
reﬂectance:

Aerosol-‐free
transmission
Aerosol
eﬀect
on

along
the
op9cal
path
length
gaseous
absorp9on

Airmass
(op9cal
path
length):

1:
[Douté
and
Ceamanos,
IEEE
WHISPERS
2010]

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
18

BETA
RETRIEVAL
FROM
DATA

Gaseous
ver9cal

¡  Iobs:
CRISM
observa9on
transmission
is
known

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
19

BETA
RETRIEVAL
FROM
DATA
BETA
LOOK-‐UP-‐TABLE
(LUT)

¡  Iobs:
CRISM
observa9on
¡  DISORT-‐based
LUT

Surface
altered

by
a
given
AOT

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
20

BETA
RETRIEVAL
FROM
DATA
BETA
LOOK-‐UP-‐TABLE
(LUT)

¡  Iobs:
CRISM
observa9on
LUT

AOT
is
retrieved
by

ﬁyng
the
observed

Reﬂectance

β
to
the
LUT

Beta

Airmass
Airmass

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
21

BETA
RETRIEVAL
FROM
DATA
BETA
LOOK-‐UP-‐TABLE
(LUT)

¡  Iobs:
CRISM
observa9on
LUT

AOT
is
retrieved
by

ﬁyng
the
observed

Reﬂectance

β
to
the
LUT

Beta

Airmass
Airmass

¡  Retrieved
AOT
is
robust
compared
to
on-‐ground
measurements!

CRISM
obs.
334D
7D6C
812F
929F
95B8
B6B5
3192
553B
8CE1
CDA5

AOT
β-‐method
0.46
1.41
1
0.42
0.36
0.46
0.38
1.0
0.4
0.33

AOT
PanCam
MER
0.55
1.29
0.9
0.64
0.44
0.47
0.31
0.81
0.59
0.41

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
22

remote
sensing
of
Mars

¡  Retrieval
of
atmospheric
opacity

¡  Retrieval
of
surface
reﬂectance

¡  Valida9on
on
the
Gusev
crater

and
perspec9ves

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
23

¡  Inverse
problem

Surface
BRDF
CRISM
data

x=(x1,…,xn)
y=(y1,…,yn)

F(·∙):
physical
model

x=F-‐1(y)

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
24

AOT
retrieved
by
the

¡  Inverse
problem
β-‐method

Op9cal
proper9es
of

aerosols
[Wolﬀ
et
al.
2009]

Surface
BRDF
CRISM
data
Correc9on
for
atmospheric

x=(x1,…,xn)
y=(y1,…,yn)
gases
[Douté
2009]

Geometric
ancillary

x=F-‐1(y)
data
(θ0,θ,ϕ)

F(·∙):
physical
model

Lamber9an
assump9on

BRDF(θ0,θ,ϕ,λ)=BRDF(λ)

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
25

AOT
retrieved
by
the

¡  Inverse
problem
β-‐method

Op9cal
proper9es
of

aerosols
[Wolﬀ
et
al.
2009]

Surface
BRDF
CRISM
data
Correc9on
for
atmospheric

x=(x1,…,xn)
y=(y1,…,yn)
gases
[Douté
2009]

Geometric
ancillary

x=F-‐1(y)
data
(θ0,θ,ϕ)

F(·∙):
physical
model

Lamber9an
assump9on

BRDF(θ0,θ,ϕ,λ)=BRDF(λ)

The
surface
of
Mars
is

not
Lamber9an!
(e.g.

regoliths,
CO2
ice)

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
26

AOT
retrieved
by
the

¡  Inverse
problem
β-‐method

Op9cal
proper9es
of

aerosols
[Wolff
et
al.
2009]

Surface
BRDF
CRISM
data
Correc9on
for
atmospheric

x=(x1,…,xn)
y=(y1,…,yn)
gases
[Douté
2009]

Geometric
ancillary

x=F-‐1(y)
data
(θ0,θ,ϕ)

F(·∙):
physical
model

¡  MARS-‐ReCO:
Mul%-‐angle
Approach
for
Retrieval
of

Surface
Reflectance
for
CRISM
Observa%ons1

Goal…
Solu9on!

Non-‐Lamber%an
surface
Semi-‐empirical
Ross-‐Thick
Li-‐Sparse
(RTLS)
model

Efficient
look-‐up
table
(LUT)
RT
formula%on
based
on
the
Green’s
func%on
of
the
atmosphere

Fast
&
robust
inversion

Least-‐square
strategy
based
on
a
matrix
inversion

1:
This
work
is
based
on
the
MAIAC
algorithm
for
MODIS
[Lyapus%n
et
al.
2011]

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
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-‐
27

¡  Ross-‐Thick
Li-‐Sparse
BRDF
model
[Lucht
et
al
2000]

Lamber9an

coeﬃcient

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
28

Li-‐Sparse
BRDF
model
[Lucht
et
al
2000]

Geometrical

Lamber9an
op9cal

coeﬃcient
coeﬃcient

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
29

Li-‐Sparse
BRDF
model
[Lucht
et
al
2000]

Geometrical

op9cal
Volumetric

Lamber9an
coefficient

coefficient
coefficient

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
30

Li-‐Sparse
BRDF
model
[Lucht
et
al
2000]

Geometrical

op9cal
Volumetric

Lamber9an
coefficient

coefficient
coefficient

¡  Top-‐of-‐atmosphere
reflectance
[Lyapus9n
et
al
2011]

RTLS
mul9plying
factors

§  Quasi-‐linear
expression!

IEEE
IGARSS.
July
29
2011
Xavier
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-‐
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-‐
31

Li-‐Sparse
BRDF
model
[Lucht
et
al
2000]

Geometrical

op9cal
Volumetric

Lamber9an
coefficient

coefficient
coefficient

reflectance
[Lyapus9n
et
al
2011]

Atmospheric
path
reflectance

RTLS
mul9plying
factors

expression!

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
32

Li-‐Sparse
BRDF
model
[Lucht
et
al
2000]

Geometrical

op9cal
Volumetric

Lamber9an
coefficient

coefficient
coefficient

reflectance
[Lyapus9n
et
al
2011]

Atmospheric
path
reflectance

RTLS
mul9plying
factors

Non-‐linear
term

expression!

IEEE
IGARSS.
July
29
2011
Xavier
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33

¡  Inversion
for
RTLS
coeﬃcients
Fiyng
the
LUT

to
each
CRISM

§  Itera9ve
least-‐squares
minimiza9on
photometric

curve
R

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
34

¡  Inversion
for
RTLS
coefficients
Fiyng
the
LUT

to
each
CRISM

§  Itera9ve
least-‐squares
minimiza9on
photometric

curve
R

§  Matrix
inversionetrieval
validity

Sufficient
angular
sampling:
μmax−μmin
≥
0.2

Retrieval
of

Exclusion
of
outliers:
|Rmeas-‐RLSRT|<0.05
BRDF
RTLS

Posi9vity
of
retrieved
direct-‐beam
albedo:
q>0
coefficients
K

IEEE
IGARSS.
July
29
2011
Xavier
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35

¡  Inversion
for
RTLS
coefficients
Fiyng
the
LUT

to
each
CRISM

§  Itera9ve
least-‐squares
minimiza9on
photometric

curve
R

§  Matrix
inversion

Retrieval
of

BRDF
RTLS

coefficients
K

§  Checking
the
retrieval
validity

1.  Sufficient
angular
sampling:
μmax−μmin
≥
0.2
Checking
the

robustness
of

2.  Exclusion
of
outliers:
|Rmeas-‐RLSRT|<0.05
retrieved
BRDF

3.  Posi%vity
of
retrieved
direct-‐beam
albedo:
q>0

IEEE
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29
2011
Xavier
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36

¡  Sensi9vity
study

§  Tes9ng
MARS-‐ReCO
under
extreme
atmospheric
and

geometric
condi9ons

4
mineral
components

observed
by
the
Mars

Explora9on
Rovers

Reference
Hapke
BRDF

DISORT

model
[Johnson
2006]

Depending
on
AOT,
θ0,
CRISM-‐like

φ,
and
#
of
available
simulated

measurements
data
sets

IEEE
IGARSS.
July
29
2011
Xavier
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-‐
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-‐
37

¡  Sensi9vity
study

§  Tes9ng
MARS-‐ReCO
under
extreme
atmospheric
and

geometric
condi9ons

4
mineral
components

observed
by
the
Mars

Explora9on
Rovers

Reference
Hapke
BRDF

DISORT

model
[Johnson
2006]

Depending
on
AOT,
θ0,
CRISM-‐like

φ,
and
#
of
available
simulated

measurements
data
sets

MARS-‐
Retrieved
RTLS

ReCO

BRDF
model

inversion

IEEE
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29
2011
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38

¡  Sensi9vity
study

§  Tes9ng
MARS-‐ReCO
under
extreme
atmospheric
and

geometric
condi9ons

4
mineral
components

observed
by
the
Mars

Explora9on
Rovers

Reference
Hapke
BRDF

Reference
BRF
DISORT

model
[Johnson
2006]

Depending
on
AOT,
θ0,
CRISM-‐like

?
φ,
and
#
of
available

measurements

simulated

data
sets

MARS-‐
Retrieved
RTLS

Retrieved
BRF
ReCO

BRDF
model

inversion

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
39

¡  Sensi9vity
study
according
to…

Aerosol
op9cal
thickness
Sun
zenith
angle
Azimuthal
sampling

¡  Unsa9sfactory
retrievals
for…

§  High
AOT,
for
dark
surfaces
especially

§  High
SZA

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
40

¡  Sensi9vity
study
according
to…

Aerosol
op9cal
thickness
Sun
zenith
angle
Azimuthal
sampling

retrievals
for…

§  High
AOT,
for
dark
surfaces
especially

ϕ0=0º

§  High
SZA

§  Poor
azimuthal
sampling
Azimuthal
plane

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
41

¡  Sensi9vity
study
according
to…

Aerosol
op9cal
thickness
Sun
zenith
angle
Azimuthal
sampling

retrievals
for…
180º
0º

§  High
AOT,
for
dark
surfaces
especially

§  High
SZA

§  Poor
azimuthal
sampling

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
42

¡  Sensi9vity
study
according
to…

Aerosol
op9cal
thickness
Sun
zenith
angle
Azimuthal
sampling

retrievals
for…
150º

§  High
AOT,
for
dark
surfaces
especially

§  High
SZA

30º

§  Poor
azimuthal
sampling

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
43

¡  Sensi9vity
study
according
to…

Aerosol
op9cal
thickness
Sun
zenith
angle
Azimuthal
sampling

120º

retrievals
for…

§  High
AOT,
for
dark
surfaces
especially

§  High
SZA

60º

§  Poor
azimuthal
sampling

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
44

¡  Sensi9vity
study
according
to…

Aerosol
op9cal
thickness
Sun
zenith
angle
Azimuthal
sampling

90º

retrievals
for…

§  High
AOT,
for
dark
surfaces
especially

§  High
SZA

90º

§  Poor
azimuthal
sampling

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
45

Retrieval
conﬁgura9on

SZA=70º

AOT=1.0

¡  Sensi9vity
study
according
to…
SZA=70º

ϕ={0º,180º}

Reference:

Retrieved:

retrievals
for…

§  High
AOT,
for
dark
surfaces
especially

§  High
SZA

§  Poor
azimuthal
sampling
Error:

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
46

Retrieval
conﬁgura9on

SZA=70º

AOT=1.0

¡  Sensi9vity
study
according
to…
SZA=70º

ϕ={0º,180º}

Reference:

Retrieved:

retrievals
for…

§  High
AOT,
for
dark
surfaces
especially

§  High
SZA

§  Poor
azimuthal
sampling
Error:

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
47

Retrieval
conﬁgura9on

SZA=70º

AOT=1.0

¡  Sensi9vity
study
according
to…
SZA=70º

ϕ={0º,180º}

Reference:

Retrieved:

retrievals
for…

§  High
AOT,
for
dark
surfaces
especially

§  High
SZA

§  Poor
azimuthal
sampling
Solu9on:
combina9on
Error:

of
mul9ple
CRISM

observa9ons

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
48

remote
sensing
of
Mars

¡  Retrieval
of
atmospheric
opacity

¡  Retrieval
of
surface
reﬂectance

¡  Valida9on
on
the
Gusev
crater

and
perspec9ves

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
49

¡  Valida9on
of
retrieved
surface
BRF1

§  Gusev
crater:
landing
site
of
MER-‐A
“Spirit”

▪  Surface
photometry
measured
at-‐ground
by
PanCam2

Proposed
atmospheric

correc9on
PanCam
Hapke

CRISM

BRDF
model

observa%ons

AOT
retrieval

β-‐method

?

BRF
retrieval

MARS-‐ReCO
CRISM
Hapke

BRDF
model

1:
[Fernando
et
al.
EPSC
2011],
2:
[Johnson
et
al.
JGR
2006]

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
50

¡  Selec9on
of
4
CRISM
observa9ons

FRT3192! FRT553B! FRT8CE1! FRTCDA5!

3!
4! 2!
1!

¡  Inversion:

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
51

¡  Fusion
of
three
observa9ons

§  Higher
angular
sampling!

¡  Photometric
regression
over
4
terrain
units
at
750
nm

Hapke
parameters
retrieved
from
CRISM
data
compared
with
PanCam

Meas.Param.
w
θ
b
c

CRISM

0.69-‐0.72
18-‐19
0.22-‐0.25
0.46-‐0.57

MARS-‐ReCO

Spirit
“Soil”

0.69
11
0.24
0.48

[Johnson
2006]

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
52

¡  Fusion
of
three
observa9ons

§  Higher
angular
sampling!

regression
over
4
terrain
units
at
750
nm

Hapke
parameters
retrieved
from
CRISM
data
compared
with
PanCam
Parameters
‘b’
and
‘c’
compared
to
synthe9c
surfaces1

Meas.Param.
w
θ
b
c

CRISM

0.69-‐0.72
18-‐19
0.22-‐0.25
0.46-‐0.57

MARS-‐ReCO

Spirit
“Soil”

0.69
11
0.24
0.48

[Johnson
2006]

CRISM
data

1:
[McGuire
et
al.
1995]

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
53

¡  Fusion
of
three
observa9ons

§  Higher
angular
sampling!

regression
over
4
terrain
units
at
750
nm

Hapke
parameters
retrieved
from
CRISM
data
compared
with
PanCam
Parameters
‘b’
and
‘c’
compared
to
synthe9c
surfaces1

Meas.Param.
w
θ
b
c

CRISM

0.69-‐0.72
18-‐19
0.22-‐0.25
0.46-‐0.57

MARS-‐ReCO

Spirit
“Soil”

0.69
11
0.24
0.48

[Johnson
2006]

CRISM
data

Soil?

1:
[McGuire
et
al.
1995]

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
54

Soil!

Spirit
Rover
on
Husband
Hill

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
55

remote
sensing
of
Mars

¡  Retrieval
of
atmospheric
opacity

¡  Retrieval
of
surface
reﬂectance

¡  Valida9on
on
the
Gusev
crater

and
perspec9ves

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
56

¡  Robust
strategy
for
retrieval
of
AOT
and
BRDF!

§  Non-‐Lamber9an
surface

§  Fast
and
accurate
because
of
atm.
Green’s
func9on

§  Retrieved
proper9es
agree
with
previous
studies

▪  PanCam
data
[Johnson
et
al.
2006]
-‐>
only
2
sites
on
Mars!

▪  Larger
coverage
of
CRISM!

¡  Remaining
issues:

§  Test
MARS-‐ReCO
on
icy
surfaces

▪  Challenging
scenario:
high
SZA,
CO2
ice
is
very
anisotropic,
…

Xavier
Ceamanos,
S.
Douté1,
A.
Lyapus9n2,
J.
Fernando3
and
P.
Pinet3

1
Ins%tut
de
Planétologie
et
d’Astrophysique
de
Grenoble,
France

2
NASA
Goddard
Space
Flight
Center,
USA

3
IRAP,
Toulouse,
France

IEEE
IGARSS
2011
–
July
29,
2011

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
58

¡  LUT
genera9on

§  Basic
principles
as
MISR/MODIS
retrieval
algorithms

▪  Eﬃcient:
realis%c
variability
vs.
reasonable
size

§  Dense
geometric
and
AOT
grid

▪  φ=[0º
:
3º
:
180º]

▪  μ0=[0.15
:
0.02
:
0.97];
θ0=[14º
-‐
81º]

▪  μ=[0.34
:
0.02
:
1];
θ=[0º
-‐
70º]

▪  AOT=[0,
0.05,
0.1,
0.2,
0.33,
0.5,
0.75,
1.0,
1.4,
2,
2.8,
4]

▪  Independent
on
the
surface!

§  ~50
MB
per
CRISM
spectral
band

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
59

¡  Example
according
to
AOT

SZA=20º
SZA=45º
SZA=70º

Hapke

reference

BRF

AOT=3.0

SZA=30º

ϕ={0º,180º}

RTLS

retrieved

BRF

180º
0º

Error

between

Hapke
and
AOT=1.0

SZA=30º

RTLS

ϕ={0º,180º}

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
60

¡  Sensi9vity
study
according
to…

Number
of
available
geometries

retrievals
for…

§  High
AOT,
for
dark
surfaces
especially
<
11
available
angular
measurements
!

§  High
SZA

§  Poor
azimuthal
sampling

§  3
or
less
available
samples

IEEE
IGARSS.
July
29
2011
Xavier
CEAMANOS
-‐
IPAG
-‐
61

¡  Hapke
photometric
model
[Hapke
1993]

w:
single
scaiering
albedo
B:
opposi9on
eﬀect
θ:
macroscopic
roughness

p:
phase
func9on

c:
backscaiering
frac9on
b:
asymmetry
parameter

ceamanos_igarss.pdf

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ceamanos_igarss.pdf