Arctic National Wildlife Refuge

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Roger Marchand Thomas Ackerman JISAO
Arctic National Wildlife Refuge and the Beaufort
Sea August 16, 2000
Multi-angle Imaging Spectro- Radiometer
Welcome to the MISR Data Users Workshop MISR A
Multiangle View of Earth
http//www-misr.jpl.nasa.gov/
Thanks David J. Diner and the entire MISR
science Team
nadir image, 1 December 2000
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Observational attributes
Polar Orbit with 400-km swath Contiguous zonal
coverage 9 days at equator 2 days at poles 275
m sampling 7 minutes to observe each scene at
all 9 angles
9 CCD pushbroom cameras 9 view angles at Earth
surface 70.5º. 60.0º, 45.6º, 26.1º forward of
nadir nadir 26.1º, 45.6º, 60.0º, 70.5º backward
of nadir 4 spectral bands at each angle 446,
558, 672, 866 nm 14-bit digitization On-board
calibration system
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Why multi-angle?
1. Change in reflectance with angle distinguishes
different types of aerosols, and surface structure
2. Oblique slant paths through the atmosphere
enhance sensitivity to aerosols and thin cirrus
3. Stereo imaging provides geometric heights of
clouds and aerosol plumes
4. Time lapse from forward to backward views
makes it possible to use clouds as tracers of
winds aloft
5. Different angles of view enable sunglint
avoidance or accentuation
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Stereo-imaging

• A significant advantage of the MISR CTH retrieval
  is that the technique is purely geometric and has
  little sensitivity to the sensor calibration.
• The retrieval has been the focus of several
  studies including Marchand et al. (2007), Naud et
  al. (2002, 2004, and 2005a,b), Seiz et al.
  (2005), Marchand et al. (2001).

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Clouds over Florida and Cuba 6 March 2000
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Clouds over Florida and Cuba 6 March
2000 cloud-top heights
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Wind retrievals
von Karman vortex street, Guadalupe Isl. 11 June
2000
Hurricane Debby 21 August 2000
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Monthly Gridded Height-Resolved Winds
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Radiometric angular signatures
Forward-viewing MISR camera
MISR flight direction
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Radiometric angular signatures
Backward-viewing MISR camera
MISR flight direction
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Visualizing surface texture
nadir blue band
nadir green band
nadir red band
multi-spectral compositing
Hudson and James Bays 24 February 2000
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Visualizing surface texture
stratocumulus cloud
70º forward red band
nadir red band
70º backward red band
pack ice (rough)
fast ice (smooth)
multi-angular compositing
Cloud-ice discrimination L. Di Girolamo and M.
Wilson (2003) IEEE TGARS 41 T. Shi, B. Yu, E.
Clothiaux, A. Braverman
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Distinguishing sea ice types
A. Nolin et al. (2002), TGARS
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Antarctica, 27 January 2001
Darwin Glacier
Mulloch Glacier
Byrd Glacier
N
50 km
nadir true color
A. Nolin et al. (2002) IEEE TGARS 40
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Antarctica, 27 January 2001
blue ice
firn
crevasses
clouds
red 70.5o green 0o blue -70.5o
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Spectral vs. angular signatures of ice
Spectral Little difference between blue ice and
crevasse region
Reflectance
Angular Strong difference between blue ice and
crevasse region
Reflectance
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Changes in ice sheet surface roughness
correlation with airborne lidar
multiangle image
Surface morphology is influenced by ice
accumulation, ablation, and melt. Spatial and
temporal changes in ice sheet roughness are
revealed in MISR data.
roughness index 28 Apr 2002 (pre-melt)
roughness index 3 Sep 2002 (post-melt)
Jakobshavn glacier, Greenland
A. Nolin et al. (2002), TGARS
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Mapping of woody shrub encroachment in arid
grasslands with MISR

• The abundance of woody shrubs in arid grasslands
  of the southwest US has been changing rapidly,
  altering carbon and energy fluxes
• Strengths of multiangle remote sensing include
• Sensitivity to vegetation structure, owing to
  effects of shadowing
• Ability to distinguish canopy and understory
  reflectance due to contrast differences between
  nadir and oblique views
• Accuracy improvements in vegetation community and
  land cover classifications

Looking in the Forward-scattering direction
shadows are VISIBLE
Looking in the Backscattering direction shadows
are HIDDEN
M. Chopping
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Community type classification in arid grasslands
Overall classification accuracy increased from
45 (nadir only) to 77 (with MISR). For 5 of 19
classes, the improvement was 50 percentage points.
Sevilleta National Wildlife Refuge
M. Chopping
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Dependence of bidirectional reflectance
on surface vegetation subpixel structure
parametric approach
Structurally homogeneous canopy representation
composed of finite-sized scatterers
bowl shape k lt 1

• Parametric models
• (e.g., Rahman-Pinty-Verstraete function)
• BRF BRF0 Shape term Asymmetry term
• Shape term mm0(mm0)k-1

Structurally heterogeneous canopy representation
composed of clumped ensembles of finite-sized
scatterers
Exponent k establishes whether BRF angular
signature gets darker off-nadir (bell-shaped, k
gt 1) or brighter off-nadir (bowl-shaped, k lt 1)
bell shape k gt 1
B. Pinty, N. Gobron, J-L. Widlowski, M. Verstraete
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Relationship between surface vegetation
bidirectional reflectance and canopy structure
bowl shape k lt 1
Manitoba and Saskatchewan, 17 April 2001
Bell-shaped BRF Tree crowns of medium-high
density against bright background Bowl-shaped
BRF Sparse vegetation and dense, closed canopies
bell shape k gt 1
k-parameter
B. Pinty, N. Gobron, J-L. Widlowski, M. Verstraete
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Sunglint as a source of information on surface
wind speed
AirMISR data over the Chesapeake Lighthouse
8/2/2001
2000-2002 MISR-retrieved surface wind speed
compared to NOAA National Data Buoy Center (NDBC)
measurements (13 sites near California and
Hawaii) RMS error 3 m/s (all points) 1 m/s
(without outliers)
D. Fox, E. Gonzales, R. Kahn, J.
Martonchik, submitted to Rem. Sens. Environ.
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Angular signature of clouds
South Pacific 11 June 2000
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Retrieval of Cloud Phase and Ice Crystal Habit
using a Combination of MISR and MODIS Radiances

• Sally McFarlane Pacific Northwest National
  Laboratory
• Roger Marchand University of Washington

Above Scattering phase function for several
crystal habits. Left Examples of retrieved
cloud phase and crystal habit. McFarlane and
Marchand, JGR 2005, 2008.
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San Joaquin Valley 3 January 2001 nadir
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Lava Butte wildfire
San Joaquin Valley 3 January 2001 70º forward
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MISR sensitivity to aerosol particle properties
Phase function
Scattering angle (deg)
O. Kalashnikova et al. (2005), JGR
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Canary Islands in a dust storm 29 February 2000
Maritime models
Dusty
nadir
70º
best-fitting model
Industrial
Clean
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Mapping particulate air pollution
MISR column optical depths are scaled to PM2.5
using a chemical transport model (GEOS-CHEM)
Y. Liu et al. (2005), JGR
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ATMOSPHERIC SCIENCE
DATA CENTERs
Later today we will have a detailed talk about
where and how to get MISR data http//eosweb.la
rc.nasa.gov But now lets talk a bit about what
is available
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Primary Level 1 Standard Products
Level 1 standard products Level 1B2 browse
(JPEG) Level 1B2 geometric parameters Level
1B2 radiometric camera-by-camera cloud mask
Level 1B2 georectified radiance product,
global and local modes ??ellipsoid
projected ??terrain (blocks containing land
only) projected Level 1 processing operates on
each camera individually
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MISR geolocation and angle-to-angle
coregistration
Space Oblique Mercator projection minimizes
resampling distortions 233 unique paths
in 16-day repeat-cycle of Terra orbit
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Objects along a camera line-of-sight have
multiple locations on the Space Oblique
Mercator grid
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Primary Level 2 Standard Products
Level 2 standard products Level 2AS
aerosol Level 2AS land surface Level 2TC
stereo Level 2TC top-of-atmosphere albedo Level
2TC classifiers Level 3 Global Summaries
http//eosweb.larc.nasa.gov/PRODOCS/misr/level3/
overview.html
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Where to get help and information LaRC DAAC
User Services larc_at_eos.nasa.gov Langley
Atmospheric Sciences Data Center DAAC
http//eosweb.larc.nasa.gov MISR home
page http//www-misr.jpl.nasa.gov We welcome
your feedback and questions! Ask MISR feature
on the MISR web site
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Data quality and maturity levels
PLEASE be sure to read the quality statements
!!! http//eosweb.larc.nasa.gov/PRODOCS/misr/Qual
ity_Summaries/misr_qual_stmts.html
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Depiction of Multi-scale Modeling Framework (MMF)
Analysis of Multiscale Modeling Framework (MMF)
Global Climate Model Using Histograms of Cloud
Top Height and Optical Depth
2.5
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64 CRM columns x 4 km 256 km
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Tropical Western Pacific (2001)
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Thin Cirrus over BL Cloud
MISR View 866 um
MISR CTP (approx).
ISCCP CTP (DX)
MODIS CTP (MOD06, collection 5)
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Combining ISCCP and MISR High Mid Level Cloud
to estimate Multilayer Cloud
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Courtesy C. Jakob
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GCSS Pacific Cross Section Transect(August 2001)
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GCSS Pacific Cross Section Transect(August 2001)
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Summary Remarks

• There are notable differences in the CTH-OD
  histograms being produced by the ISCCP, MISR and
  MODIS projects.
• These differences have their roots in the
  different algorithms used both to detect clouds
  and to retrieve the cloud height and optical
  depth.
• Rather than be disturbed by these differences, we
  can and should take advantage of what they tell
  us about the observed cloud fields.
• Provides measure of uncertainty
• Combined ISCCP and MISR to examine Multilayer
  Clouds
• We have constructed a MISR simulator to
  facilitate comparison of model data with MISR
  retrievals. I am currently adding this
  simulator to the suite of instrument simulators
  in the CFMIP Observation Simulator Package (COSP).