Download Application of Hyperspectral Data Bio-science

Application of Hyperspectral
Data
Bio-sciences
Lammert Kooistra and Michael Schaepman
Wageningen University
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Introduction
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Introduction
• Bio-science applications originating from imaging
spectrometer data products are in most cases indirectly
derived and require the use of ‘models’ (e.g., radiances –
PRI – LUE – DVM – Biodiversity).
• Directly derived bio-science applications from imaging
spectrometer data are sparse (e.g., LUCC) or often site
specific.
• Wageningen UR (CGI) is currently focusing on the
integration of imaging spectrometer data derived
products into dynamic vegetation models.
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Applications I
• Variables
– Mostly being used as input for a model that needs to
produce a spatially explicit output
• Parameters
– Mostly being used to constrain a model or other
parameters (not too much relevance for the biodomain)
• Applications
– Higher level product the involves the use of
{statistical, physical} models
• Products
– Can be any of the above
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Applications II
• Relevant Bio-Science Variables
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At-sensor radiance
Surface reflectance
(Spectral) Albedo
fAPAR
fCover / gap fraction
LAI
Leaf/canopy pigments (Chlorophyll, Xantophyll, Cellulose, etc.)
Leaf/canopy water
Leaf/canopy dry matter
Foliage temperature
Soil temperature
fLiving/fDead biomass (litter) / SOC
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Applications III
•
Relevant Bio-Science Products
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Albedo
Efficiency (Light Use, Water Use, Rain Use)
LUCC, VCC
GPP, aNPP, NPP
Biodiversity
Ecosystem, habitat, species distribution
Crop growth and yield estimation
Plant stress (nitrogen; water)
Forest inventories (e.g., forest area, forest type, fragmentation, biomass, stem
volume, crown diameter)
Carbon sequestration (reforestation, afforestation, deforestation)
Ecosystem resilience
Ecosystem services
Fire (health, water stress, fuel type, activation energy)
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Application IV
• Imaging spectroscopy measures radiance (with
spatial (2D), spectral, temporal, directional (2D),
and polarization dependencies)
• However the reflectance of a canopy is a
function of its geometry, structure, biochemistry,
and geochemistry.
• We employ mainly quantitative statistical or
physical models (or a combination of both) to
bridge the gap that imaging spectroscopy cannot
measure any of the canopy parameters directly
(sometimes this is (erroneously) referred to as
being the ill-posed problem)
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Example I
fAPAR
PRI
ANPP (LUE approach)
MJm-2day-1
Regional estimates of aboveground Net Primary Productivity (aNPP)
for a river floodplain
Issues:
- Regional scale ecosystem modeling
- DVM initialisation, calibration and validation
- Scenario development including human impact
Aduaka, U. et al., 2006
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Example II
Species abundance maps
fAPAR
PFT1: Grazed Grassland
PRI
PFT2: mixed herb
Issues:
- Level of detail increases with increasing spatial
resolution
- Many RTM’s are sensitive to the shadow fraction
- Parameterizations of models need to account
horizontal competition
Spatial abundance map for
Rubus caesius based on
combined approach of SMA and
radiative transfer modelling
Liras, E. et al., 2005
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Example III
Field / Laboratory Observations
Radiative Transfer Modelling (DART)
v = 48°
v = 225°
RGB =
NIR,G,B
OFF-NADIR simulated
forest stand
Laboratory measurement of the needle optical properties
RGB = NIR,G,B
Spatial (3D) measurement of the tree structural parameters
DART 3D spruce „mock-up“
NADIR simulated forest
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
Malenovsky, Z. et al.,
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Example IV
Three Gorges Region,China
EO-1 Hyperion data
Issues:
-Bridging scaling gaps from local to regional
-Combined physical and statistical model calibration
-Assessing ecosystem services
Zheng, Y. et al., 2006
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Example V
l
h
Seasonal Patterns - Fused images
0.9
0.8
NDVI values
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0.5
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cerrado
eucalyptus
0.1
pasture
"new" cerrado
0
Jan
M arch
April
M ay
June
July
Aug
Tim e of the year
Sept
Nov
Dec
Acerbi, F. et al., 2006
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
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Example VI
Sub-pixel Land Cover mapping with MERIS
Identification of
endmembers
Reference
dataset (LGN)
Sub-pixel accuracy
Issues:
-Requirement to map LUCC at high spatial resolution
-Vegetation Cover Conversion (state vectors)
-Phenology
Zurita-Milla, R. et al., 2006
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
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Developments I
• Bridging scaling gaps will be come more
relevant (genetics – molecules – leaves –
plants – canopies – ecosystems)
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Developments II
• In-situ networks (SensorWeb), data
assimilation and applied optimal
estimation methods will further constrain
degrees of freedom
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Developments III
• In coupled human-environment systems
monitoring of transitional zones (ecotones
– habitat, ecosystem boundaries) deserve
more attention
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Developments IV
• Holistic views striving to describe the Earth
System better in all relevant aspects will
result in more detailed spectroscopic
analysis
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Developments V
• 3-D radiative transfer approaches in partly
cloudy atmospheres
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Developments VI
• Biochemical applications concentrate on
the retrieval of moisture content, C, N, and
(potentially) P cycles
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Developments VII
• Coupled systems (soil-vegetationatmosphere transfer (SVAT)) must
emphasize on the soil component
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Discussion Points
• Imaging spectroscopy of vegetation is one of the most
challenging applications in remote sensing due to the
multitude of simultaneously influencing factors and that
none of the measurements is a direct measurement
• Semantic interoperability is the (unexplored) link
between remote sensing and vegetation research (PFT,
Albedo, reflectance, etc.)
• In characterizing the SVAT (soil-vegetation-atmospheretransfer) scheme, the S remains the least explored so far
(no parametric soil model avaiable)
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions
Discussion Points
• Spectral band redundancy discussions should be
replaced with full spectral coverage discussions, making
use of the contiguity criterion of spectral measurements
• Spectroscopy has most significantly advanced the
understanding of interactions of photons with vegetation.
We are looking forward for photon-matter interactions.
• Spectroscopy alone will not be able to solve current
issues to the full extend: we need phenology (time
series), ground measurements (data assimilation), and
other technologies (fluorescence, SAR, LIDAR, etc.) to
complement spectroscopy
SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006
HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions