Stanford B. Hooker,
Giuseppe Zibordi,
Jean-François Berthon,
and James W. Brown
S. B. Hooker (stan@ardbeg.gsfc.nasa.gov) is with the Laboratory for Hydrospheric Processes, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771. USA
G. Zibordi and J.-F. Berthon are with the Joint Research Centre, Institute for Environment and Sustainability, Ispra I-21020, Italy.
J. W. Brown is with the Department of Meteorology and Physical Oceanography, Rosenthal School of Marine and Atmospheric Science, University of Miami, Miami, Florida 33149. USA
Stanford B. Hooker, Giuseppe Zibordi, Jean-François Berthon, and James W. Brown, "Above-water radiometry in shallow coastal waters," Appl. Opt. 43, 4254-4268 (2004)
Above- and in-water radiometric data were collected from two coastal platforms: a small boat and an oceanographic tower. The above-water data were processed with and without a correction for bidirectional effects (Q02 and S95, respectively). An intercomparison of water-leaving radiances over a wide range of environmental conditions showed (a) total uncertainties across the blue-green domain were to within 4%, (b) a convergence of the Q02 method with the in-water method (average Q02 intercomparisons were to within 4%), and (c) chlorophyll a concentrations derived from Q02 reflectances and the OC4V4 (Ocean Color 4 Version 4) algorithm agreed with independent high-performance liquid-chromatography determinations to within approximately 32%.
Tristan Harmel, Alexander Gilerson, Soe Hlaing, Alberto Tonizzo, Tom Legbandt, Alan Weidemann, Robert Arnone, and Samir Ahmed Appl. Opt. 50(30) 5842-5860 (2011)
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Summary of the Major Quantities Defining the Environmental Conditions for the ADRIA-2000 and CoASTS Stations Providing Simultaneous Above- and In-Water Match-Ups (43 for ADRIA-2000 and 27 for CoASTS)a
The minimum-to-maximum range of the variables are shown followed by the average.
Computed as the diffuse-to-direct-downward-irradiance ratio and excluding stations with overcast sky conditions.
Coded according to the World Meteorological Organization27 scale, where a sea state of 0, 1, and 2 is related to wave heights within 0–0.1, 0.1–0.5, and 0.5–1.25 m, respectively.
Determined by high-performance liquid-chromotography analysis.
Table 2
Summary of the Major Sources of Uncertainties in the Computation of Water-Leaving Radiances for Representative Blue (443-nm), Green (555-nm), and Red (665-nm) Wavelengthsa
The red wavelength is not part of the above-water instrumentation used in this study, so it is omitted and is presented for the in-water instrumentation to completely document the level of effort applied to the uncertainty analysis. Note that the uncertainty from bidirectional effects is arbitrarily apportioned to the above-water instruments because the correction is associated with the Q02 method, but it would be equally appropriate to correct the in-water viewing to match the above-water viewing rather than the reverse. The last two rows give the net uncertainties assuming the indicated sources combine in quadrature (square root of the sum of the squares); the former is for all the controllable uncertainties (items 1–6), and the latter is for all the uncertainties (items 1–7).
Representative of the uncertainty in as a result of typical uncertainties in the input parameters used to calculate these quantities and not the intrinsic uncertainties in the tables themselves.
Only the in-water observations are actually corrected for platform perturbations (in this case, primarily tower shading); the above-water measurements were made under circumstances that significantly minimized this source of uncertainty.
Table 3
Summary of the Above- and In-Water Intercomparisons for the ADRIA-2000 Data Based on the Average RPD Values for the Individual Wavelengths, Spectral Averages, and Band Ratiosa
Water Type
Above-Water
Wavelength (nm)
Spectral Average
Band Ratio
Method
Calibration
412
443
490
510
555
443/555
490/555
510/555
Case 1
Q02
Satlantic
6.3
5.4
-2.3
0.3
1.5
2.3
4.5
-2.9
-0.3
S95
Satlantic
8.6
9.4
4.0
7.2
9.3
7.7
0.6
-4.3
-1.4
Q02
JRC
5.1
4.9
-1.8
0.4
0.0
1.7
5.5
-1.1
1.2
Case 2
Q02
Satlantic
4.0
3.9
-4.1
-3.2
-1.0
-0.1
5.3
-2.8
-2.0
S95
Satlantic
6.1
7.7
2.0
3.1
5.9
5.0
2.0
-3.5
-2.5
Q02
JRC
3.3
3.5
-3.8
-3.5
-2.8
-0.7
6.7
-0.8
-0.6
The results are separated according to the water type, the above-water method, and the calibration facilities used for the above-water sensors. The in-water sensors were all calibrated at the JRC, so a complete intercalibration of all the sensors occurs only when the above-water sensors were also calibrated at the JRC.
Table 4
Summary of the CoASTS (AAOT) Statistical Intercomparisons Based on the Average RPD Values and the Partitioning Established with Table
3
Water Type
Above-Water
Wavelength (nm)
Spectral Average
Band Ratio
Method
Calibration
412
443
490
510
555
443/555
490/555
510/555
Case 1
Q02
Satlantic
3.9
3.1
0.6
-5.9
0.6
0.5
2.6
0.1
-6.4
S95
Satlantic
4.7
5.5
5.6
-1.1
6.0
4.2
-0.3
-0.3
-6.7
Q02
JRC
3.2
3.8
2.9
-3.1
5.0
2.3
-1.0
-1.9
-7.7
Case 2
Q02
Satlantic
5.2
5.9
-0.8
-3.2
6.9
2.8
-0.9
-7.2
-9.5
S95
Satlantic
8.2
10.2
4.9
2.3
13.4
7.8
-2.8
-7.5
-9.7
Q02
JRC
4.6
5.1
-0.2
-2.1
6.3
2.7
-1.3
-5.8
-8.2
Tables (4)
Table 1
Summary of the Major Quantities Defining the Environmental Conditions for the ADRIA-2000 and CoASTS Stations Providing Simultaneous Above- and In-Water Match-Ups (43 for ADRIA-2000 and 27 for CoASTS)a
The minimum-to-maximum range of the variables are shown followed by the average.
Computed as the diffuse-to-direct-downward-irradiance ratio and excluding stations with overcast sky conditions.
Coded according to the World Meteorological Organization27 scale, where a sea state of 0, 1, and 2 is related to wave heights within 0–0.1, 0.1–0.5, and 0.5–1.25 m, respectively.
Determined by high-performance liquid-chromotography analysis.
Table 2
Summary of the Major Sources of Uncertainties in the Computation of Water-Leaving Radiances for Representative Blue (443-nm), Green (555-nm), and Red (665-nm) Wavelengthsa
The red wavelength is not part of the above-water instrumentation used in this study, so it is omitted and is presented for the in-water instrumentation to completely document the level of effort applied to the uncertainty analysis. Note that the uncertainty from bidirectional effects is arbitrarily apportioned to the above-water instruments because the correction is associated with the Q02 method, but it would be equally appropriate to correct the in-water viewing to match the above-water viewing rather than the reverse. The last two rows give the net uncertainties assuming the indicated sources combine in quadrature (square root of the sum of the squares); the former is for all the controllable uncertainties (items 1–6), and the latter is for all the uncertainties (items 1–7).
Representative of the uncertainty in as a result of typical uncertainties in the input parameters used to calculate these quantities and not the intrinsic uncertainties in the tables themselves.
Only the in-water observations are actually corrected for platform perturbations (in this case, primarily tower shading); the above-water measurements were made under circumstances that significantly minimized this source of uncertainty.
Table 3
Summary of the Above- and In-Water Intercomparisons for the ADRIA-2000 Data Based on the Average RPD Values for the Individual Wavelengths, Spectral Averages, and Band Ratiosa
Water Type
Above-Water
Wavelength (nm)
Spectral Average
Band Ratio
Method
Calibration
412
443
490
510
555
443/555
490/555
510/555
Case 1
Q02
Satlantic
6.3
5.4
-2.3
0.3
1.5
2.3
4.5
-2.9
-0.3
S95
Satlantic
8.6
9.4
4.0
7.2
9.3
7.7
0.6
-4.3
-1.4
Q02
JRC
5.1
4.9
-1.8
0.4
0.0
1.7
5.5
-1.1
1.2
Case 2
Q02
Satlantic
4.0
3.9
-4.1
-3.2
-1.0
-0.1
5.3
-2.8
-2.0
S95
Satlantic
6.1
7.7
2.0
3.1
5.9
5.0
2.0
-3.5
-2.5
Q02
JRC
3.3
3.5
-3.8
-3.5
-2.8
-0.7
6.7
-0.8
-0.6
The results are separated according to the water type, the above-water method, and the calibration facilities used for the above-water sensors. The in-water sensors were all calibrated at the JRC, so a complete intercalibration of all the sensors occurs only when the above-water sensors were also calibrated at the JRC.
Table 4
Summary of the CoASTS (AAOT) Statistical Intercomparisons Based on the Average RPD Values and the Partitioning Established with Table
3