Comparisons of Satellite Derived Optical

1
Comparisons of Satellite Derived Optical
Properties to In Situ Coastal Measurements at
LEO 2001
L. Alex Kahl, Michael Crowley, Oscar
Schofield, Robert Arnone, John Kerfoot,Trish
Bergmann,
Inst. Of Marine and Coastal Sciences Rutgers
University New Brunswick, NJ Naval Research Lab
Stennis, MS California Polytechnic State
University San Luis Obispo, CA
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What are We Working Towards?
We want to calibrate Inherent Optical Properties
(IOP) estimates from space in turbid CASE 2
waters. We want to incorporate satellite IOP
derived Bio-optical models.
EcoSim
0.14 0.13 0.12 0.11 0.10 0.09 0.08 0.07 0.06 0.05
0.04 0.03 0.02 0.01
0.10 0.085 0.07 0.055 0.04 0.025 0.01
Depth (m)
Phytoplankton Pigment (mg/m3)
Phytoplankton Pigment (mg/m3)
Range (km)
Range (km)
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The Goals of My Talk

• Discuss Adaptive sampling of the coastal waters
  at LEO 2001
• Assess the correlations between In Situ and
  satellite derived AOPs and IOPs

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Calibration of the LEO Remote Sensing Platforms

• 5 Aircraft - PHILLS, PHILLS-2, AVIRIS, Proteus
  SPECTIR
• 4 Ships RV Endeavor, RV Walford, RV Arabella, RV
  Caleta
• HydroRad
• TSRB
• ac-9
• HydroScat 6
• An Optical Robotic Node 400 profiles

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1000s km2
100s km2
10s km
1 point
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FY1-C vs. SeaWiFS
SeaWiFS
FY-1C
Afternoon
Morning

Chlor-a
Chlor-a
Research
Research
Area
Area
A cloud-free FY1-C pass over LEO area.
Typical afternoon cumulus obstruct SeaWiFS view
of LEO.
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Satellite Geometry to Validate SeaWiFS Data
Omitted from regression l
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Processing, and not the sensor has limited
SeaWiFS products in CASE 2 waters. 1
SeaWiFS
SeaWiFS
Channel 5
Channel 5
August 1, 2001
Enhanced
August 1, 2001
Haze/ Humidity f f
0.1 Pixel Values 45
0.1 Pixel Values 4.0
1Arnone, R.A., P. Martinolich, R.W. Gould, R.
Stumpf, S. Ladner, Coastal Optical Properties
Using SeaWiFS, Ocean Optics XIV Conference
Papers Vol. 1, 1998
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Cross-calibrating Products USA China
FY1-C Chlor-a
August 2, 2001
1231 GMT
Chlor-a
3
mg/m
0.2
1
2
40N
3
Field
Station
4

6
38N
In Situ measured chlorophyll-a SeaWiFS derived
chlorophyll-a
76W
74W
72W
70W
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Cross-calibrating Products USA India
SeaWiFS Chlor-a
Oceansat Chlor-a


August 2, 2001
August 2, 2001
1746 GMT
1710 GMT
Chlor-a
Chlor-a
mg/m3
mg/m3
0.5 1 3 5 7
0.5 1 3 5 7
40N

• f f
• j j
• f f

Oceansat has a ground resolution ? 360 m.
SeaWiFS has a ground resolution ? 1100 m.
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Corrections using CODAR HF - RADAR

• Frontal Boundary
• f
• f
• f
• f
• f

Field Station

• Corrected Image
• r2 improved from
• 0.69 to 0.75
• Slope moved closer to 1
• Intercept moved closer to 0

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July 23, 2001 Arnones SeaWiFS derived Rrs r2
AOP Correlations
Wavelength
August 2, 2001 Arnones SeaWiFS derived Rrs r2
In Situ vs. Satellite Remote Sensing
Reflectance Generally 0.60lt r2 lt0.90
Wavelength
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IOPs derived from Rrs
1
For coastal waters
a(?) 0.051 bb(?) / Rrs Using the Petzold
volume scattering function 2 bb(?) ? 0.02 b(?)
1Arnone, R.A., P. Martinolich, R.W. Gould, R.
Stumpf, S. Ladner, Coastal Optical Properties
Using SeaWiFS, Ocean Optics XIV Conference
Papers Vol. 1, 1998.
2 Gould, R.W., R.A. Arnone and P. Martinolich
Spectral Dependence of the Scattering Coefficient
in CASE 1 and Case 2 Waters,, Applied Optics
Volume 38, Issue 12, 2377-2383, April 1999.
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Inherent Optical Properties from Space
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IOP Maps
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IOP Transects
bb 532
a 488
0 5 10 15 20 25
0 5 10 15 20 25
0.02 0.016 0.012 0.008 0.004 0
0.9783 0.7826 0.587 0.3913
0.1957 0
Depth (m)
mg/m3
Depth (m)
mg/m3
0 2 4 6 8 10 12 14 16
0 2 4 6 8 10 12 14 16
Range (km)
Range (km)
RV Walford transects during LEO 2001
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Future Goals

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Conclusions
Human quality assurance of imagery is still
necessary in coastal oceans.
Access to wide array of space based data allows
for multiple satellite passes in one day and
subsequent adaptive sampling .
Satellite derived IOPs that we verified using
ship based data show promise, even in CASE 2
turbid waters.
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Acknowledgements
Shelly Blackwell, Christina Orrico, Paul
Bissett, Sherwin Ladner, Rick Gould, Liz Creed,
Bob Chant, Josh Kohut, Sage Lichtenwalner, Paul
Marlinovich, Dave Kohler, the crew of the RV
Endeavor, Fred Grassle
Want to download this talk? http//marine.rutgers
.edu/cool/agu2002
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g g g g
fLEO
fLEO

• i
• m l

FY-1C Relative Azimuth peak is 180 at LEO
SeaWiFS Relative Azimuth peak is 60 at LEO
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Apparent Optical Properties
Wavelength
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Old Point
l R2 increased gt 0.06
Slope closer to
1Intercept closer to 0 Corrected
Point i
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j h Good Days
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Slope lt1 For all wavelengths