Remote Sensing of Kelp Dynamics

NASA IDS Meeting

6/4/2007

SPOT Imagery and Kelp

• Two types of images: 10 m multispectral (4 bands); 5 m panchromatic (b&w)

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Wavelength (nm)

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Mature Kelp R

Immature Kelp R

Senescent Kelp R

Seawater

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400 450 500 550 600 650 700 750 800 850 900 950 1000

Wavelength (nm)

Ref

lect

ance

(re

l)

Mature Kelp R

Immature Kelp R

Senescent Kelp R

Seawater

SP

OT

ban

d 3

(NIR

)

SP

OT

ban

d 2

(red

)

SP

OT

ban

d 1

(gre

en)

Multispectral

Panchromatic

SPOT Imagery Collection

Jan 2006-present All of SBC (multispectral

and b&w: 18 scenes) every 6-8 weeks

Near futureAdding Monterrey Bay, Palos Verdes, San Onofre, Pt. Loma

Oct 2004-Jan 2006 ~16 multispectral scenes on 4 different dates: 10/04; 11/04; 12/04; 04/05Majority are of SB coast; no islands

Satellite derived datasets

1. Canopy Cover

2. Biomass

Kelp Canopy Delineation• After atmospheric and geometric corrections…• Use NIR/green ratio

– Pixels of kelp show higher ratios

• Validated against CDFG 2m aerial NIR survey

SPOT 3,2,1 imageSPOT 3,2,1

stretched image3(NIR)/1(green)

band ratio Kelp delineation

Satellite Biomass Estimation• Normalized Difference Vegetation Index (NDVI)

(NIR-RED)(NIR+RED)

• Calculated for areas of kelp cover

NDVITransform

NDVI Comparison with LTER SCUBA Measurements

• Attempting to account for tides/currents on canopy exposure

• Look at relationship with LAI

r2 = 0.63p < 1*10-7

r2 = 0.51p < 1*10-5

Classification Progress

• Canopy cover for most SB scenes from Oct 2004-Nov 2006 (no islands yet)

• Need to redo biomass estimations (atmospheric correction problem)

• Hiring 2 undergraduate imagery classifiers to help clear the imagery backlog…

Next Steps

• Methods paper for Remote Sensing of the Environment in progress

• Follow up paper on seasonal and spatial variations in kelp abundance on various scales

Data Management and Distribution to SBC-LTER

• Currently I have all the raster layers and shapefiles of canopy cover for classified scenes

• What format to give to SBC-LTER?– Area/biomass per administrative bed