Transcript Coral Reef Remote Sensing Spectral, Spatial, Temporal Scaling Phillip Dustan

Coral Reef Remote Sensing
Spectral, Spatial, Temporal Scaling
Phillip Dustan
Sensor
Spatial
Resolutio
n
80m
Number
of Bands
2
Useful
Bands
2
coverage
cycle
18
Operation
Thematic
Mapper
SPOT pan
30m
7
3
16
1982-97
10
1
1
26
1986-97
SPOT XS
20m
3
2
26
1986-97
IRS
6m
CZCS
1km
6
5
7 approx.
1978-86
SeaWiffs
1km
8
6
Daily
1997
AVHRR
1km
4
2
Daily
1972
Landsat
1972-97
IKONOS
Launch Date September 24, 1999
Athena II Vandenberg AFB, Ca
Ground resolution of each band:
1-meter panchromatic < 26deg off nadir
4-meter multispectral < 26deg off nadir
The ground processing software has the capability to rapidly
process and mosaic imagery so as to create seamless image
products with a consistent pixel ground sample distance (GSD)
IKONOS Relative Spectral Response and
Radiometric
Imagery Spectral Response
Panchromatic: 0.45 - 0.90 microns
Multispectral:
#1: Blue
0.45 - 0.52
#2: Green 0.52 – 0.60
#3: Red
0.63 - 0.69
#4: Near IR 0.76 - 0.90
Spectral Bands same as Landsat TM 4&5 Bands #1-4
Swath Widths & Scene Sizes
Nominal swath width: 11 km at nadir
Areas of interest a nominal single image 13 km x 13 km
Strips of 11km x 100 km up to 11km x 1000 km
Image mosaics of up to 12,000 sq.km.
Up to two 10,000 square kilometer contiguous
in a single pass within a region
Metric Accuracy
12-meter horizontal and 10-meter vertical
accuracy with no ground control
2-meter horizontal and 3-meter vertical accuracy
with ground control
(Specified as 90% CE (circular error) for the horizontal and 90% LE
(linear error) for the vertical.
Orbital Information
98 Minute Sun synchronous Agile spacecraft
in-track and cross-track pointing
Altitude 423 miles / 681 kilometers
Inclination 98.1 degrees
Speed 4 miles per second / 7 kilometers per second
Descending nodal crossing time 10:30 a.m.
Revisit frequency for targets at 40 degrees latitude
2.9 days at 1-meter resolution;
1.5 days at 1.5-meter resolution
Revisit times will be more frequent for higher latitudes
and less frequent for latitudes closer to the equator.
Mapping
How do we detect and differentiate between
major groups of reef communities:
Coral
Seagrasses
Sand
Rubble
Hard algal pavements
Wavelngth
(nm)
410
443
SeaWiFS
Animal
Fluorescence
Algal
Type
Photosynthetic
Pigment
Interest
All
Chlorophyll a
Absorption max
Brown
Fucoxanthin, Peridinin
Absorption max
412
443
450
480
485
490
500
510
510
515
540
550
550
570
Blue-green
Type 1 peak **
Green
Type 2 peak **
Blue-green
Type 1 shoulder**
Green
Type 3 peak **
Red,
Bluegreen,
Phycobilins
Red
Phycobilins
Absorption max
Brown
Chlorophyll c
Absorption max
All
Chlorophyll a
Absorption max
All
Chlorophyll a
Natural Fluorescence
All
Chlorophyll minimum
Chlorophyll reflectance
CZCS hinge point
600
630
675
670
683
690
700
765
Atmosphere
865
Atmosphere
Radiometric vs GIS Approach
Classification of different habitat using cluster
analysis - cluster busting approach
Detection of habitats using analytical
radiometric techniques
Combine radiometric and GIS spatial/textural
target identification
Identification of threats and water “qualities”
Merge with other types of sensors
How do we detect differences in coral
reef condition?
Colony level - scale too small
Community/ ecological zone:
Bleaching - albedo
change algal abundance- albedo
spectral
textural
Video Transects
3 video transects per station
3-5 minutes of tape per transect
120 images per transect
180 non-overlapping images
sampled per station
Wavelength
Landsat1
TM / Ikonos
Panchromatic
Spot pan1
SPOT xs1
510-730
Blue
JERS
IRS 1
IRS-2S
500-700
500-700
AVHRR2
450-520*
Green
500-600
*520-600
*500-590
Red
600-700
*630-690
*610-680
580-680
Infrared
700-800
760-900
790-890
725-1100
Infrared
8001100
1500-1750
3550-3930
Infrared
10400-12500
10500-11300
Infrared
20800-23500
11500-12500
Pixel at nadir
80m
1 Sabin, 1996, 2. Kidwell, 1983,
30m
10m
20m*
5.8m
5.8m?
1km
Florida Keys
Put reef map here
For keys as a whole system
Reef Variability: Temporal Texture
Coral Reef Degradation
1985
1995
Carysfort Reef,
Florida Keys, USA
KEY: “algae”
“substrate”
“coral-dominated” “sand”
Live coral cover per year
60
Percent Coral
50
40
30
20
10
0
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
Year
1984 Landsat-Classified Image
satellite
in situ
1999 Landsat-Classified Image
•Satellites can provide an accurate synoptic time series of coral reef
degradation from space corroborating in situ data.
David Palandro, Serge Andréfouët, Phillip Dustan, and Frank E. Muller-Karger
Reefs at Risk
African Dust
Spectral
Signatures
Wavelength (nm)
CZCS
SeaWifs
Blue400-500)
412
443
443
490
Green (500-600)
520
510
550
550
670
670
750
765
Red (600-700)
Infrared
865
OCTS
Mesoamerican
Barrier Reef
Modis
MODIS:
Mesoamerican Atolls
urbanization
predation
M
a
n
Sediments
Carnivores
predation
predation
eutrophication
Inorganic
Nutrients
attenuation &
smothering
photosynthesis
Disease Phytoplankton
infection
attenuation
Herbivores
herbivory
Benthic Algae
competition
Reef corals
Meteorological Perturbations:temperature, turbulence, UV, etc
Thanks for listening