Kahn, Ralph A.

Limbacher, James A.

NASA Technical Reports Server

MISR Eyjafjallajökull & Grimsvötn Retrievals 
Ralph Kahn & James Limbacher
NASA Goddard Space Flight Center
Eyjafjallajökull Volcano Ash Plume – MISR Aerosol Retrieval – April 19, 2010
MISR Team, JPL and GSFC
https://ntrs.nasa.gov/search.jsp?R=20150021057 2019-08-31T05:51:28+00:00Z
Multi-angle Imaging 
SpectroRadiometer
• Nine CCD push-broom cameras
• Nine view angles at Earth surface:
70.5º forward to 70.5º aft
• Four spectral bands at each angle:
446, 558, 672, 866 nm
• Studies Aerosols, Clouds, & Surface
http://www-misr.jpl.nasa.gov
http://eosweb.larc.nasa.gov
MISR flight direction
plume
height
Forward-viewing
camera
apparent position
Changes in geometric
perspective with angle
Diner & Kahn, 2003
MISR flight direction
plume
height
Backward-viewing
camera
parallax
Changes in geometric
perspective with angle
Diner & Kahn, 2003
D. Nelson and the MISR Team, JPL and GSFC
km
0
2
4
6
Eyjafjallajökull Volcano
MISR Stereo-Derived Plume Heights
07 May 2010 Orbit 55238 Path 216 Blks 40-43 UT 12:39
D. Nelson and the MISR Team
Eyjafjallajökull Volcano
MISR Stereo-Derived Plume Heights
07 May 2010 Orbit 55238 Path 216 Blks 40-43 UT 12:39
Height: Blue = Wind-corrected
Plume 1
Plume 2
Ht ~ 0.25 - 2 km
Mode < 1 km
Ht ~ 2.25 – 6 km
Mode ~ 4.8 km
Plume 2
Plume 1
Etna Volcano
MISR Stereo-Derived Plume Heights
Scollo et al., JGR 2012
12
3
4
5
1
2
3
4
5
0.0 0.6 1.2 0.0 1.2 2.4 0 5000 10,000
Oregon Fire  Sept 04 2003 
Orbit 19753 Blks 53-55 MISR Aerosols V17, Heights V13 (no winds)
Kahn, et al., JGR 2007
19753 
0
2
4
6
8
10
0 2 4 6 8 10
Atmospheric Stability
H
e
ig
h
t 
(k
m
)
P 1-2
P 4-5
fire.19753.b55Sub1_hist
0 50 100
0.5
1.5
2.5
3.5
4.5
5.5
6.5
7.5
8.5
9.5
H
e
ig
h
t 
(k
m
)
Number of Pixels
P1
fire.19753.b55 Sub2_hist
0 100 200
0.5
1.5
2.5
3.5
4.5
5.5
6.5
7.5
8.5
9.5
H
e
ig
h
t 
(k
m
)
Number of Pixels
P2
fire.19753.b55 Sub3_hist
0 50 100
0.5
1.5
2.5
3.5
4.5
5.5
6.5
7.5
8.5
9.5
H
e
ig
h
t 
(k
m
)
Number of Pixels
P3
fire.19753.b55 Sub4_hist
0 50 100
0.5
1.5
2.5
3.5
4.5
5.5
6.5
7.5
8.5
9.5
H
e
ig
h
t 
(k
m
)
Number of Pixels
P4
fire.19753.b55 Sub5_hist
0 20 40 60
0.5
1.5
2.5
3.5
4.5
5.5
6.5
7.5
8.5
9.5
H
e
ig
h
t 
(k
m
)
Number of Pixels
P5
The Cloud-Aerosol Lidar and Infrared Pathfinder 
Satellite Observations (CALIPSO)
Omar et al., JAOT 2009
MISR Aerosol Type Discrimination
Kahn & Gaitley JGR 2015
July 2007January 2007
1-10 31-4011-20 41-50 51-6221-
30
63-70 71-74
Mixture Group
Spherical, non-absorbing
Spherical, absorbing
Non-spherical
0.5 < AOD < 1.0
SEAC4RS – MISR Overview  19 August 2013
*
Site 2 
Smoke Plume 1
AOD 0.35-0.9
ANG 1.5-1.9 (small)
SSA 0.94-0.98 (absorbing)
FrNon-Sph 0-0.2  (mostly sph.)
Smoke Plume 2
AOD 0.35-0.6
ANG 1.6-2.0 (smaller)
SSA 0.96-0.98 (less abs.)
FrNon-Sph 0-0.1 (more 
sph.)
Continental Background
AOD 0.15-0.2
ANG 1.0-1.5 (medium)
SSA 0.99-1.0 (non-abs.)
FrNon-Sph 0.0 (spherical)
Effectively larger, less 
absorbing particles in 
Plume 2 than Plume 1. 
Larger yet in Plume 3. 
Largest in background.
Smoke
Plumes
Site 3
Site 2
Continental-
Smoke Mix
1
2
3
Five Aerosol Air Masses:
• Three Smoke Plumes
• Continental Bkgnd.
• Continental-Smoke Mix
Passive-remote-sensing Aerosol Type is a Total-Column-Effective, Categorical variable!!
Kalashnikova & Kahn, JGR 2006
Single-scattering Phase Functions for Different Particle Shapes
Single-scattering Phase Functions for Different Particle Types
Kahn et al., JGR 2001
Mount Etna Plume Height and Eruption Style from MISR
Scollo, S. R.A. Kahn, D.L. Nelson, M. Coltelli, D.J. Diner, M.J. Garay, and V.J. Realmuto
MISR observations of Etna volcanic plumes. J. Geophys. Res. 2012
MISR nadir-viewing, true-color image showing Etna, 
with stereo-derived plume height superposed
29 Sept. 2006 – MISR retrieved mostly small spherical
particles, indicating a sulfate/water-dominated plume
Mount Etna
MISR stereo heights for the ash-dominated 
plume on 30 December 2002
Indications of Eruption Strength:
• Plume Height from MISR stereo imaging
• Ash to Sulfate/Water particle AOD ratio from MISR-retrieved particle shape and size
Mount Etna Plume Height and Eruption Style from MISR
Scollo et al., JGR 2012
MISR Research Aerosol Retrieval 
MISR components & Mixtures
32 Components, 1200 mixing groups, 343200 mixtures 
MISR Research Aerosol Retrievals
07 May 2010 Orbit 55238 Path 216 Blks 40-43 UT 12:39
Kahn & Limbacher, ACP 2012
Fr. Non-Sph.
0.00
0.6
0
0.80
0.40
1.00
0.20
P1
P2
P3
P4
C
S
SSA
0.80
0.92
0.96
0.88
0.84
1.00
ANG
0.75
0.35
0.55
0.15
-0.05
-0.25
AOD
3.50
2.30
1.70
1.10
0.50
2.90
100 km
Plume Particles
• Distinct from background
-- larger, darker
-- much higher AOD
• Non-spherical dominated
• Brighten downwind
• Tend to decrease in size
downwind
3.3 km retrievals
MISR Research Aerosol Retrievals 
(AOD, particle properties)
07 May 2010 Orbit 55238 Path 216 Blks 40-42 UT 12:39
4.4 km retrievals
MISR Research Aerosol Retrievals 
(AOD, particle properties)
07 May 2010 Orbit 55238 Path 216 Blks 40-42 UT 12:39
4.4 km retrievals
ANG
0.75
-
0.25
0.25
SSA
1.0
0.8
0.9
Fr. 
Spherical 
Absorbing
0.50
0.10
0.30P
Fr. 
Cirrus
0.50
0.10
0.30P
MISR Research Aerosol Retrievals
16 April 2010 Orbit 54931 Path 197 Blk 49 UT 10:45
Kahn & Limbacher, ACP 2012
• 1-2 days downwind of 
Iceland volcano source
• Distinctly high AOD 
(peak >1.25)
• Retrieved ~50% AOD 
non-spherical dust grains
• Medium particles ~ no “cirrus”
• Model back-trajectory needed
to identify plume confidently
50 km
0.50
0.10
0.30
Fr. Spherical 
Non-
absorbing
P
Fr. Non-
Sph.
1.0
0.0
0.5P
AOD
1.25
0.75
1.0
Fr. Dust 
Grains
0.50
0.10
0.30P
3.3 km retrievals
Grimsvötn Volcano
19 April 2010 Orbit 54976 Path 218 Blks 39-42 UT 12:51
MISR 70˚ forward browse image
MINX Stereo Height Map
MISR Research Aerosol Retrievals 
(AOD, particle properties)
19 April 2010 Orbit 54976 Path 218 Blks 39-42 UT 12:51
MISR Summary
• ~ Weekly global coverage – good primarily for retrospective analysis, 
but not for real-time analysis in most cases
• AOD, Plume Height, Ash/Sulfate (aerosol type) are all available 
from MISR where coverage of volcanic plumes exists
• Free troposphere aerosols tend to be transported long distances
in relatively thin layers of relative atmospheric stability
• Good optical analogs for volcanic ash at visible wavelengths 
are needed as input to the satellite retrievals
Satellites
Model Validation
• Parameterizations
• Climate Sensitivity
• Underlying mechanisms
CURRENT STATE
• Initial Conditions
• Assimilation
Remote-sensing Analysis
• Retrieval Validation
• Assumption Refinement
frequent, global 
snapshots;
aerosol amount & 
aerosol type maps, 
plume & layer heights
space-time interpolation, 
Aerosol Direct & 
Indirect Effects
calculation and prediction
Suborbital
targeted chemical & 
microphysical detail
point-location
time series
Regional Context 
Adapted from: Kahn, Survy. Geophys. 
2012
Aerosol-type
Predictions;
Meteorology;
Data integration
Must stratify the global satellite 
data to treat appropriately 
situations where different 
physical mechanisms apply 
Backup Slides
Grimsvötn Volcano
MINX Stereo Heights & Winds
19 April 2010 Orbit 54976 Path 218 Blks 39-42 UT 12:51
MISR Standard Stereo Height Map
~ 2.5 km
Orbit 54976: No Volcanic Ash MaskingMISR Research Aerosol Retrievals 
(AOD, particle properties)
19 April 2010 Orbit 54976 Path 218 Blks 39-42 UT 12:51


MISR Eyjafjallajokull and Grimsvotn Retrievals

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