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CHAPTER 11CHAPTER 11CHAPTER 11:CHAPTER 11:Remote Sensing ofRemote Sensing of

VegetationVegetationREFERENCE: Remote Sensing REFERENCE: Remote Sensing of the Environment of the Environment John R. Jensen (2007)John R. Jensen (2007)Second EditionSecond EditionPearson Prentice HallPearson Prentice Hall

gg

THE EARTH'S SURFACETHE EARTH'S SURFACE

The earth's surface. This is a composite of numerous satellite images, each selected to becloud-free. It is unrealistic because, at any moment, half of the Earth is in nighttimedarkness and much of it is cloud-covered. But this beautiful image lets us view the entiresurface at once. It shows densely vegetated regions in green, dry deserts in yellow orbrown, and ice-covered regions in white.

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VEGETATION INDEXVEGETATION INDEX

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Remote Sensing of Vegetation Remote Sensing of Vegetation

Spectral Spectral CharacteristicsCharacteristicsCharacteristicsCharacteristics

Dominant Factors Controlling Leaf Reflectance

Water Water absorption

bands:0.97 m1.19 m1.45 m1.94 m2.70 m

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Cross-section Through A

Hypothetical and fReal Leaf

Revealing the Major Structural Components that

Determine the Spectral

Reflectance of Vegetation

Interaction of leaf structurewith visible and NIR radiation

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Absorption Spectra of Chlorophyll a and b,

-carotene, Pycoerythrin, and Phycocyanin Pigments

orpt

ion

Effi

cien

cy

Chlorophyll a

Chlorophyll bAbsorption Spectra

of Chlorophyll a and b

lack of absorption

0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7violet blue green yellow red

Abs

o

PhycoerythrinPhycocyanin

ncy

a. Wavelength, m

Chlorophyll apeak absorption is at 0.43 and 0.66 m.

Chlorophyll bpeak absorption is at 0 45 and 0 65 m

-carotene

0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7violet blue green yellow red

Wavelength, m

Abs

orpt

ion

Effic

ien

b.

0.45 and 0.65 m.

Optimum chlorophyll absorption windows are:

0.45 - 0.52 m and 0.63 - 0.69 m

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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.

Spectral Reflectance

Characteristics of

SweetgumLeaves

(Liquidambar styraciflua L.)

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1 2

a

3

Spectral Reflectance

Characteristics of Selected

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Green leaf

Yellow

145

40

a.

b.

c.

Areas ofBlackjack Oak

Leaves

0

5

10

15

20

25

30

35

Blue (0.45 - 0.52 m)

Perc

ent R

efle

ctan

ce

Yellow

Red/orange

Brown 4

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Green (0.52 - 0.60 m)

Red (0.63 - 0.69 m)

Near-Infrared (0.70 - 0.92 m)

d.

Hemispherical Reflectance, transmittance, and Absorption Characteristics of Big Bluestem Grass

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Hypothetical Example of

Additive Reflectance

from A Canopy with

Two Leaf Layers

Distribution of Pixels in a Scene in Red and Near-infrared Multispectral

Feature Space

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Reflectance Response of a Single Magnolia Leaf

(Magnolia grandiflora) to Decreased Relative Water Content

Airborne Visible

Infrared Imaging

Spectrometer Spectrometer (AVIRIS)

Datacube of Sullivans

Island Obtained on October 26,

1998

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Imaging Spectrometer Data of Healthy Green Vegetation in the San Luis Valley of Colorado Obtained on

September 3, 1993 Using AVIRIS

224 channels each 10 nm wide with 20 x 20 m pixels

Hyperspectral Analysis of

AVIRIS Data Obtained on

September 3, 1993 of San Luis Valley,

Colorado

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Goniometer in Operation at North Inlet, SC

Remote Sensing of Vegetation Remote Sensing of Vegetation

Temporal Temporal ((PhenologicalPhenological) ) CharacteristicsCharacteristicsCharacteristicsCharacteristics

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Predicted Percent Cloud Cover in Four Areas in the United States

Phenological Cycle of Hard Red Winter Wheat in the Great Plains

Winter Wheat Phenology

snow cover

JULJUNMAY AUGAPRMARFEBJANDECNOVOCTSEP

crop establishment

10 14

greening up heading mature

14 14 21 13 425 7 9 5 21 29 34 28 108 days 50

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Sow TilleringEmergence

Dormancy Growth resumes

Heading Boot

Dead ripe

Hard doughSoft dough

Harvest

Jointing

Maximum Coverage

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Phenological Cycles of San Joaquin and

Imperial Valle Valley,

California Crops and Landsat

Multispectral Scanner Scanner

Images of One Field During A

Growing Season

LandsatThematic MapperImagery

of the Band 1 (blue; 0 45 0 52m) Band 2 (green; 0 52 0 60m) Band 3 (red; 0 63 0 69m) of the Imperial Valley,

California Obtained

on

Band 1 (blue; 0.45 0.52 m) Band 2 (green; 0.52 0.60 m) Band 3 (red; 0.63 0.69 m)

Band 4 (near-infrared; 0.76 0.90 m) Band 5 (mid-infrared; 1.55 1.75 m) Band 7 (mid-infrared; 2.08 2.35 m)

December 10, 1982

Band 6 (thermal infrared; 10.4 12.5 m)

Sugarbeets

Alfalfa

Cotton

Fallow

feed lot

fl

Ground Reference

Landsat Thematic Mapper Imagery of

Imperial Valley, California, December 10, 1982

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Landsat Thematic

Mapper Color Composites

and and Classification

Map of a Portion of the

Imperial Valley, Valley,

California

Phenological Cycles of Soybeans

and Corn in S th

JUN MAY APR MAR FEB JAN DEC NOV OCT SEP

Initial growth Harvest Maturity

snow cover 25 cm height

50

75

100

125

Dormant or multicropped

Soybeans

100% ground cover

JUL AUG

Development

50%

a.

SoybeansSoybeans

South Carolina

125

150

200

250

300

Corn

100%

b.

CornCorn

JUN MAY APR MAR FEB JAN DEC NOV OCT SEP

Dent/Harvest Tassle 8-leaf

snow cover 25 cm height

50

75

Dormant or multicropped

JUL AUG

Dormant or multicropped

100

10 - 12 leaf

12-14 leaf

Blister

50%

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Phenological Cycles of Winter Wheat,

JULJUNMAY AUGAPRMARFEBJAN DECNOVOCTSEP

SeedTillering Booting HarvestJointing

snow cover 25 cm

50

75

100

100% ground cover 50%

Head Dormant or multicropped

Winter Wheat

Winter Wheat 150

a.

b. Wheat, Cotton, and Tobacco in

South CarolinaJUN MAY APR MAR FEB JAN DEC NOV OCT SEP

Seeding Maturity/harvest Boll

Winter Wheat Phenology

snow cover 25 cm height

50

75

100

125

Dormant or multicropped

Cotton

100% ground cover

JUL AUG

Fruiting

Pre-bloom

50%

125

b.

JUN MAY APR MAR FEB JAN DEC NOV OCT SEP

Development Maturity/harvest Transplanting

snow cover 25 cm height

50

75

100

125

Dormant or multicropped

Tobacco 100%

JUL AUG

Topping

50%

Dormant or multicropped

c.

Phenological Cycle of Cattails and Waterlilies in Par Pond, S.C.

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Phenological Cycle of Smooth Cordgrass (Spartina alterniflora) Biomass in South Carolina

1500Live Biomass

Smooth Cordgrass ( Spartina alterniflora )

500

750

1000

1250

eigh

t Bio

mas

s, g/

m2 Dead Biomass

J A S O N0

250

500

Dry

W

F M A M J J D

Nine Bands of 3 x 3 m

Calibrated Airborne

M ltispect al Multispectral Scanner

(CAMS) Data of Murrells Inlet, SC

Obtained on

Band 1 (blue; 0.45 0.52 m) Band 2 (green; 0.52 0.60 m) Band 3 (red; 0.60 0.63m)

Band 4 (red; 0.63 0.69 m) Band 5 (near-infrared; 0.69 0.76 m) Band 6 (near-infrared; 0.76 0.90 m) Obtained on August 2,

1997

Band 7 (mid-infrared; 1.55 1.75 m) Band 9 (thermal-infrared; 10.4 12.5 m)Band 8 (mid-infrared; 2.08 2.35 m)

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Calibrated Airborne Multispectral Scanner Data of Murrells Inlet, S.C. Obtained on August 2, 1997

Natural Color Composite

(Bands 3,2,1 = RGB)

Masked and Contrast Stretched Color Composite

Calibrated Airborne Multispectral Scanner Data of Murrells Inlet, S.C. Obtained on August 2, 1997

Color Infrared Composite (Bands

3,2,1 = RGB)

Masked and Contrast Stretched Color Composite

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Remote Sensing of Vegetation Remote Sensing of Vegetation

Instruments to Instruments to study the study the V iV iVegetationVegetation

Spectral Reflectance Measurement using a Spectroradiometer

radiometer in backpack

detector

personal computer

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In Situ CeptometerLeaf-Area-Index Measurement

LAI may be computed using a Decagon AccuparCeptometer that consists of a linear array of 80 Cepto ete t at co s sts o a ea a ay o 80adjacent 1 cm2 photosynthetically active radiation (PAR) sensors along a bar.

I id t li ht b th Q d th Incident sunlight above the canopy, Qa, and the amount of direct solar energy incident to the cept