Figure 1.
Example of quasi-true color satellite images of the Gironde Estuary on 19 April 2018. Sentinel-3-OLCI sampled at 10:37 UTC (A), Landsat-8-OLI sampled at 10:47 UTC (B) and Sentinel-2-MSI sampled at 11:01 UTC (C). Locations of the automated turbidity stations of Le Verdon (green circle) and Pauillac (blue circle) (B).
Figure 1.
Example of quasi-true color satellite images of the Gironde Estuary on 19 April 2018. Sentinel-3-OLCI sampled at 10:37 UTC (A), Landsat-8-OLI sampled at 10:47 UTC (B) and Sentinel-2-MSI sampled at 11:01 UTC (C). Locations of the automated turbidity stations of Le Verdon (green circle) and Pauillac (blue circle) (B).
Figure 2.
In-situ water-leaving reflectance () of 50 stations in the Gironde Estuary measured from 17 September 2018 to 20 September 2018.
Figure 2.
In-situ water-leaving reflectance () of 50 stations in the Gironde Estuary measured from 17 September 2018 to 20 September 2018.
Figure 3.
The relative spectral response functions of S3-OLCI, S2-MSI and L8-OLI in green, red and NIR bands.
Figure 3.
The relative spectral response functions of S3-OLCI, S2-MSI and L8-OLI in green, red and NIR bands.
Figure 4.
Using the relative spectral response of each sensor, sensor equivalent values were derived from 50 in-situ for OLI, MSI and OLCI. of MSI/OLI versus OLCI in green band (A), of MSI/OLI versus OLCI in red band (B) and of MSI/OLI versus OLCI in NIR band (C).
Figure 4.
Using the relative spectral response of each sensor, sensor equivalent values were derived from 50 in-situ for OLI, MSI and OLCI. of MSI/OLI versus OLCI in green band (A), of MSI/OLI versus OLCI in red band (B) and of MSI/OLI versus OLCI in NIR band (C).
Figure 5.
Comparisons between derived by Acolite DSF and Acolite SWIR AC algorithms from L8-OLI data recorded on 19 April 2018 over the Gironde Estuary: green band (A), red band (B) and NIR band (C).
Figure 5.
Comparisons between derived by Acolite DSF and Acolite SWIR AC algorithms from L8-OLI data recorded on 19 April 2018 over the Gironde Estuary: green band (A), red band (B) and NIR band (C).
Figure 6.
Spatial distributions of values in green, red and NIR bands obtained applying DSF (first column), iCOR-NoSIMEC (second column), C2RCC (third column) and Polymer (last column) AC algorithms to S2-MSI data recorded on 2 August 2018.
Figure 6.
Spatial distributions of values in green, red and NIR bands obtained applying DSF (first column), iCOR-NoSIMEC (second column), C2RCC (third column) and Polymer (last column) AC algorithms to S2-MSI data recorded on 2 August 2018.
Figure 7.
values derived by iCOR-NoSIMEC versus values derived by Acolite DSF (left), values derived by Polymer versus values derived by Acolite DSF (middle) and values derived by C2RCC versus values derived by Acolite DSF (right) in the 3 bands (green, red and NIR) of S2-MSI.
Figure 7.
values derived by iCOR-NoSIMEC versus values derived by Acolite DSF (left), values derived by Polymer versus values derived by Acolite DSF (middle) and values derived by C2RCC versus values derived by Acolite DSF (right) in the 3 bands (green, red and NIR) of S2-MSI.
Figure 8.
MSI-derived versus OLI-derived values in green (A), red (B) and NIR (C) bands from satellite data recorded on 19 April 2018 and 1 September 2018 with a time difference of 14 and 6 min respectively.
Figure 8.
MSI-derived versus OLI-derived values in green (A), red (B) and NIR (C) bands from satellite data recorded on 19 April 2018 and 1 September 2018 with a time difference of 14 and 6 min respectively.
Figure 9.
Spatial distributions of values derived from S3-OLCI data recorded on 19 April 2018 applying different AC algorithms. From left to right BAC, iCOR-NoSIMEC, BLR, Polymer, C2RCC-V2 and C2RCC-V1.
Figure 9.
Spatial distributions of values derived from S3-OLCI data recorded on 19 April 2018 applying different AC algorithms. From left to right BAC, iCOR-NoSIMEC, BLR, Polymer, C2RCC-V2 and C2RCC-V1.
Figure 10.
Scatter-plots between values obtained applying different AC algorithms versus BAC derived values. Each row corresponds to one band and each column corresponds to particular AC algorithm for S3-OLCI recorded on 19 April 2018.
Figure 10.
Scatter-plots between values obtained applying different AC algorithms versus BAC derived values. Each row corresponds to one band and each column corresponds to particular AC algorithm for S3-OLCI recorded on 19 April 2018.
Figure 11.
OLCI versus MSI values (green band) from satellite data recorded on 1 September 2018 with a time difference of 22 min. OLCI-BAC versus MSI-DSF (A), OLCI-iCOR-NoSIMEC versus MSI-DSF (B), OLCI-Polymer versus MSI-DSF (C), OLCI-C2RCC-V2 versus MSI-DSF (D) and OLCI-C2RCC-V1 versus MSI-DSF (E).
Figure 11.
OLCI versus MSI values (green band) from satellite data recorded on 1 September 2018 with a time difference of 22 min. OLCI-BAC versus MSI-DSF (A), OLCI-iCOR-NoSIMEC versus MSI-DSF (B), OLCI-Polymer versus MSI-DSF (C), OLCI-C2RCC-V2 versus MSI-DSF (D) and OLCI-C2RCC-V1 versus MSI-DSF (E).
Figure 12.
OLCI versus MSI values (red band) from satellite data recorded on 1 September 2018 with a time difference of 22 min. OLCI-BAC versus MSI-DSF (A), OLCI-iCOR-NoSIMEC versus MSI-DSF (B), OLCI-Polymer versus MSI-DSF (C), OLCI-BLR versus MSI-DSF (D) OLCI-C2RCC-V2 versus MSI-DSF (E) and OLCI-C2RCC-V1 versus MSI-DSF (F).
Figure 12.
OLCI versus MSI values (red band) from satellite data recorded on 1 September 2018 with a time difference of 22 min. OLCI-BAC versus MSI-DSF (A), OLCI-iCOR-NoSIMEC versus MSI-DSF (B), OLCI-Polymer versus MSI-DSF (C), OLCI-BLR versus MSI-DSF (D) OLCI-C2RCC-V2 versus MSI-DSF (E) and OLCI-C2RCC-V1 versus MSI-DSF (F).
Figure 13.
OLCI versus MSI values (NIR band) from satellite data recorded on 1 September 2018 with a time difference of 22 min. OLCI-BAC versus MSI-DSF (A), OLCI-iCOR-NoSIMEC versus MSI-DSF (B), OLCI-BLR versus MSI-DSF (C), OLCI-Polymer versus MSI-DSF (D), OLCI-C2RCC-V2 versus MSI-DSF (E) and OLCI-C2RCC-V1 versus MSI-DSF (F).
Figure 13.
OLCI versus MSI values (NIR band) from satellite data recorded on 1 September 2018 with a time difference of 22 min. OLCI-BAC versus MSI-DSF (A), OLCI-iCOR-NoSIMEC versus MSI-DSF (B), OLCI-BLR versus MSI-DSF (C), OLCI-Polymer versus MSI-DSF (D), OLCI-C2RCC-V2 versus MSI-DSF (E) and OLCI-C2RCC-V1 versus MSI-DSF (F).
Figure 14.
Satellite-derived versus in-situ SPM concentrations considering MSI/OLI (processed with Acolite DSF) (A) and OLCI (processed with BAC) satellite data (B).
Figure 14.
Satellite-derived versus in-situ SPM concentrations considering MSI/OLI (processed with Acolite DSF) (A) and OLCI (processed with BAC) satellite data (B).
Table 1.
Date (dd/mm/yyyy) and time (UTC) of cloud-free satellite observations selected over the year 2018 and corresponding hydro-dynamical conditions prevailing in the estuary at the time of satellite overpass, LW, HW, TR, SZA, Pau-AOT865 and Ver-AOT865 respectively stand for low-water, high-water, tidal range, sun zenith angle, aerosol optical thickness at 865 nm from Pauillac station and aerosol optical thickness at 865 nm from Le Verdon station.
Table 1.
Date (dd/mm/yyyy) and time (UTC) of cloud-free satellite observations selected over the year 2018 and corresponding hydro-dynamical conditions prevailing in the estuary at the time of satellite overpass, LW, HW, TR, SZA, Pau-AOT865 and Ver-AOT865 respectively stand for low-water, high-water, tidal range, sun zenith angle, aerosol optical thickness at 865 nm from Pauillac station and aerosol optical thickness at 865 nm from Le Verdon station.
Date | Tide | Tide | TR (m) | SZA () | Pau-AOT865 | Ver-AOT865 | OLCI | MSI | OLI |
---|
25/02/2018 | 06:19 LW | 12:48 HW | 3.18 | 61.19 | 0.22 ± 0.19 | 0.23 ± 0.19 | 10:11 | | |
16/04/2018 | 04:55 HW | 11:34 LW | 5.02 | 42.09 | NaN | 0.30 ± 0.20 | 10:15 | | |
19/04/2018 | 06:47 HW | 13:29 LW | 4.78 | 38.65 | 0.61 ± 0.10 | 0.26 ± 0.10 | 10:37 | 11:01 | 10:47 |
20/04/2018 | 07:31 HW | 14:08 LW | 4.41 | 41.21 | 0.38 ± 0.15 | 0.26 ± 0.11 | 10:11 | | |
04/05/2018 | 07:14 HW | 13:41 LW | 3.90 | 32.96 | 0.43 ± 0.07 | 0.56 ± 0.13 | 10:48 | 11:02 | |
05/05/2018 | 07:49 HW | 14:13 LW | 3.40 | 35.50 | 0.65 ± 0.18 | 0.38 ± 0.11 | 10:22 | | 10:46 |
20/05/2018 | 08:24 HW | 14:49 LW | 3.99 | 30.95 | 0.39 ± 0.21 | 0.25 ± 0.14 | 10:33 | | |
20/06/2018 | 10:17 HW | 16:35 LW | 3.62 | 29.17 | 0.23 ± 0.17 | 0.21 ± 0.19 | 10:30 | | |
25/06/2018 | 09:15 LW | 15:22 HW | 3.97 | 33.61 | 0.31 ± 0.19 | 0.13 ± 0.12 | 10:00 | | |
28/06/2018 | 04:57 HW | 11:18 LW | 4.10 | 30.54 | 0.40 ± 0.22 | 0.17 ± 0.16 | 10:22 | 11:06 | |
09/07/2018 | 07:26 LW | 13:40 HW | 3.58 | 29.59 | 0.32 ± 0.14 | 0.21 ± 0.06 | 10:37 | | |
10/07/2018 | 08:30 LW | 14:35 HW | 4.08 | 33.26 | 0.38 ± 0.17 | 0.23 ± 0.06 | 10:11 | | |
25/07/2018 | 09:37 LW | 15:46 HW | 3.80 | 33.96 | 0.53 ± 0.21 | 0.34 ± 0.14 | 10:22 | | |
02/08/2018 | 07:55 HW | 14:23 LW | 3.84 | 36.48 | 0.26 ± 0.18 | 0.10 ± 0.04 | 10:15 | 10:59 | |
05/08/2018 | 04:25 LW | 10:37 HW | 3.08 | 34.32 | 0.18 ± 0.14 | 0.22 ± 0.13 | 10:37 | | |
06/08/2018 | 05:33 LW | 12:01 HW | 3.05 | 37.81 | 0.23 ± 0.15 | 0.25 ± 0.10 | 10:11 | | |
18/08/2018 | 09:54 HW | 16:22 LW | 3.23 | 42.03 | 0.29 ± 0.24 | 0.19 ± 0.19 | 10:00 | | |
22/08/2018 | 08:21 LW | 14:45 HW | 3.09 | 43.50 | 0.23 ± 0.17 | 0.26 ± 0.19 | 09:57 | 11:04 | |
01/09/2018 | 08:06 HW | 14:39 LW | 3.89 | 41.52 | 0.08 ± 0.14 | 0.09 ± 0.08 | 10:37 | 10:59 | 10:53 |
02/09/2018 | 08:52 HW | 15:24 LW | 3.50 | 44.56 | 0.16 ± 0.20 | 0.44 ± 0.26 | 10:11 | | |
12/09/2018 | 06:25 HW | 13:02 LW | 5.17 | 43.82 | 0.27 ± 0.19 | 0.21 ± 0.19 | 10:52 | | |
17/09/2018 | 10:09 HW | 16:42 LW | 2.46 | 47.96 | 0.16 ± 0.13 | 0.23 ± 0.14 | 10:22 | | 10:53 |
20/09/2018 | 07:49 LW | 14:17 HW | 2.74 | 47.08 | 0.23 ± 0.26 | 0.56 ± 0.29 | 10:45 | | |
24/09/2018 | 04:18 HW | 10:43 LW | 4.40 | 48.74 | 0.24 ± 0.19 | 0.27 ± 0.23 | 10:41 | | |
Table 2.
List of atmospheric correction algorithms tested for each sensor.
Table 2.
List of atmospheric correction algorithms tested for each sensor.
L8-OLI | S2-MSI | S3-OLCI |
---|
Acolite DSF/SWIR | Acolite DSF | BAC |
iCOR (NoSIMEC and SIMEC) | iCOR (NoSIMEC and SIMEC) | iCOR (NoSIMEC and SIMEC) |
| Polymer | Polymer |
| C2RCC | BLR |
| | C2RCC-V1 |
| | C2RCC-V2 |
Table 3.
Linear fits and differences between OLCI values derived using different AC algorithms and S2-MSI/L8-OLI DSF values in green band. A total of 10 match-ups between OLCI (eight images) and MSI (six images) or OLI (four images) recorded on same day were used to generate these statistics.
Table 3.
Linear fits and differences between OLCI values derived using different AC algorithms and S2-MSI/L8-OLI DSF values in green band. A total of 10 match-ups between OLCI (eight images) and MSI (six images) or OLI (four images) recorded on same day were used to generate these statistics.
AC Algorithm | Slope | | NRMSE % | BIAS % | MAPE % |
---|
iCOR-NoSIMEC | 1.0 ± 0.15 | 0.71 ± 0.1 | 9.64 ± 4.49 | 1.98 ± 4.54 | 11.78 ± 5.05 |
iCOR-SIMEC | 1.06 ± 0.14 | 0.74 ± 0.1 | 9.42 ± 4.31 | 0.79 ± 5.10 | 11.70 ± 5.18 |
BAC | 0.73 ± 0.20 | 0.41 ± 0.29 | 15.71 ± 6.05 | −12.97 ± 4.08 | 16.72 ± 4.38 |
Polymer | 0.68 ± 0.35 | 0.49 ± 0.31 | 15.41 ± 7.57 | −14.70 ± 10.76 | 18.60 ± 6.32 |
C2RCC-V2 | 0.82 ± 0.19 | 0.39 ± 0.14 | 18.46 ± 4.37 | −16.81 ± 5.95 | 19.66 ± 3.06 |
C2RCC-V1 | 0.19 ± 0.25 | 0.13 ± 0.19 | 31.53 ± 13.79 | −27.20 ± 34.37 | 39.26 ± 14.29 |
Table 4.
Linear fits and differences between OLCI values derived using different AC algorithms and S2-MSI/L8-OLI DSF values in red band. A total of 10 match-ups between OLCI (eight images) and MSI (six images) or OLI (four images) recorded on same day were used to generate these statistics.
Table 4.
Linear fits and differences between OLCI values derived using different AC algorithms and S2-MSI/L8-OLI DSF values in red band. A total of 10 match-ups between OLCI (eight images) and MSI (six images) or OLI (four images) recorded on same day were used to generate these statistics.
AC Algorithm | Slope | | NRMSE % | BIAS % | MAPE % |
---|
iCOR-NoSIMEC | 1.0 ± 0.17 | 0.75 ± 0.12 | 10.92 ± 3.10 | −9.78 ± 8.70 | 27.85 ± 20.15 |
iCOR-SIMEC | 1.02 ± 0.14 | 0.77 ± 0.11 | 10.69 ± 3.07 | −7.65 ± 9.63 | 27.50 ± 20.32 |
BAC | 0.82 ± 0.07 | 0.7 ± 0.14 | 11.95 ± 2.77 | −17.21 ± 9.78 | 27.03 ± 16.55 |
Polymer | 0.64 ± 0.20 | 0.68 ± 0.25 | 15.5 ± 6.80 | −25.52 ± 8.15 | 30.36 ± 8.41 |
C2RCC-V2 | 0.74 ± 0.18 | 0.61 ± 0.16 | 18.02 ± 3.79 | −29.40 ± 8.76 | 31.60 ± 7.84 |
BLR | 0.66 ± 0.22 | 0.34 ± 0.11 | 21.19 ± 4.65 | −26.61 ± 7.94 | 27.78 ± 7.10 |
C2RCC-V1 | 0.22 ± 0.2 | 0.36 ± 0.28 | 32.85 ± 15.56 | −56.61 ± 8.22 | 54.75 ± 8.66 |
Table 5.
Linear fits and differences between OLCI values derived using different AC algorithms and S2-MSI/L8-OLI DSF values in NIR band. A total of 10 match-ups between OLCI (eight images) and MSI (six images) or OLI (four images) recorded on same day were used to generate these statistics.
Table 5.
Linear fits and differences between OLCI values derived using different AC algorithms and S2-MSI/L8-OLI DSF values in NIR band. A total of 10 match-ups between OLCI (eight images) and MSI (six images) or OLI (four images) recorded on same day were used to generate these statistics.
AC Algorithm | Slope | | NRMSE % | BIAS % | MAPE % |
---|
BAC | 0.70 ± 0.13 | 0.43 ± 0.17 | 12.71 ± 4.36 | −32.56 ± 17.01 | 54.69 ± 19.92 |
iCOR-NoSIMEC | 0.83 ± 0.22 | 0.38 ± 0.29 | 18.68 ± 7.75 | 11.23 ± 72.44 | 112.48 ± 96.60 |
iCOR-SIMEC | 0.89 ± 0.20 | 0.38 ± 0.28 | 19.03 ± 6.68 | −5.24 ± 68.03 | 125.07 ± 91.00 |
BLR | 0.63 ± 0.13 | 0.43 ± 0.21 | 14.0 ± 4.56 | −43.92 ± 13.79 | 60.94 ± 19.68 |
C2RCC-V2 | 0.35 ± 0.12 | 0.46 ± 0.15 | 13.89 ± 6.82 | −51.07 ± 13.88 | 54.65 ± 15.38 |
Polymer | 0.40 ± 0.09 | 0.48 ± 0.06 | 13.95 ± 8.91 | −53.84 ± 9.81 | 58.35 ± 12.93 |
C2RCC-V1 | 0.04 ± 0.04 | 0.17 ± 0.11 | 22.69 ± 14.78 | −83.37 ± 5.70 | 78.91 ± 6.37 |