ESM 266: Vegetationproperties

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ESM 266 Vegetationproperties

• Jeff Dozier

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Spectral characteristics related to leaf pigments
and water
Water vapor absorption bands 0.97 mm 1.19
mm 1.45 mm 1.94 mm 2.70 mm
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Cross-section through a leaf
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Absorption spectra of compounds
Chlorophyll a peak absorption is at 0.43 and 0.66
mm. Chlorophyll b peak absorption is at 0.45 and
0.65 mm. Optimum chlorophyll absorption windows
are 0.45 - 0.52 mm and 0.63 - 0.69 mm
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Litton Emerge Spatial, Inc., CIR image (RGB
NIR,R,G) of Dunkirk, NY, at 1 x 1 m obtained on
December 12,1998.
Natural color image (RGB RGB) of a N.Y. Power
Authority lake at 1 x 1 ft obtained on October
13, 1997.
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Seasonal variability in spectral
reflectance(Sweetgum Liquidambar styraciflua
L.)
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Spatial variability on the leaves (Blackjack oak)
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Reflectance, absorption, and transmittance
through canopy Big bluestem grass
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Tassled cap red NIR reflectance
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Reflectance increases as leaf dries
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AVIRIS image, Sullivans Island, Oct 1998
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AVIRIS image of crops, San Luis Valley CO Sept
1993
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Species and stress mapped from AVIRIS, San Luis
Valley CO Sept 1993
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Temporal variability phenological cycle of
winter wheat in Great Plains
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Phenological cycle of some San Joaquin Valley
crops
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Landsat TM imagery of Imperial Valley
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Landsat TM color composites, Imperial Valley
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Vegetation characteristics leaf-area index
LAI may be computed using a Decagon Accupar
Ceptometer that consists of a linear array of 80
adjacent 1 cm2 photosynthetically active
radiation (PAR) sensors along a bar.
Incident sunlight above the canopy, Qa, and the
amount of direct solar energy incident to the
ceptometer, Qb, when it is laid at the bottom of
the canopy is used to compute LAI.
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Field measurement of LAI
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Temporal variability of live and dead biomass
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Biomass estimated from spectral reflectance
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NDVI (normalized difference vegetation index)

• Characteristics of leaf reflectance (phenological
  stage, leafy biomass, greening, drying, etc.)

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NDVI time series for wet (1988) and dry years
(1984) in Sahel
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Other vegetation indices (condensed from p. 363
in Jensen)
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The MODIS EVI, produced every 16 days
MODIS vegetation index page, then click on VI
gallery
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Gross primary productivity, South America, Jan
2001
NTSG (Numerical Terradynamic Simulation Group)
University of Montana
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What remote sensing of vegetation has accomplished

• Terrestrial biosphere now a dynamic component of
  Earth System
• Global Ecology has emerged as a discipline

Land Classification
AVHRR-NDVI