Ver.3 Ocean Products1

Validation Results of Ocean NWLR Products:
Normalized Water-Leaving Radiance - NWLR
Major Updates of Algorithm:•••••

Added water leaving reflectance estimation model in the red(VN07) and near-infrared(VN10)
bands using Linear combination index (LCI)
Applied the vicarious calibration
Improved sunglint correction method
Added negative NWLR correction
Revision of QA flags and Mask for statistics

Validation Method:
Validated the accuracies of predicted NWLR data from the SGLI algorithm comparing within-situ data: ship observation, buoy(MOBY and BOUSSOLE) and AERONET-OC

Quality Control:••In-situ data: time difference in ±3 hours to SGLI observation
SGLI data: average of the data passed the following conditions within a 5 by 5 pixel
centered the in-situ point (for details refer to Bailey et al, 2006)
1. 13 or more pixels which satisfies the following conditions: aerosol optical
thickness < 0.5, solar zenith angle < 70 degrees, NWLR of all channels > 0,CLDAFFCTD flag isn’t set.
2. Median CV (coefficient of variation) computed from NWLR_380-565nm
and Taua_865nm less than 0.15

Period of Validation:•January 1, 2018 - May 31, 2022
2

Validation Results of Ocean NWLR Products:
Normalized Water-Leaving Radiance - NWLR
380nm

412nm

443nm

490nm

530nm

Achv. Standard

Achv. Standard

Achv. Standard

Achv. Target

Achv. Target

N=1005
Accuracy
41.7%

N=154
Accuracy
39.1%
565nm

673.5nmAchv. Target

Not Achv. Stnd

N=1005
Accuracy
23.5%

N=1005
Accuracy
34.6%
673.5nm

Remove in-situ
data on lakes

N=1005
Accuracy:
0.62 W/m2/sr/um

Achv. Standard

N=1005
Accuracy
23.4%

N=1005
Accuracy
20.9%

•

N=945
Accuracy:
0.49 W/m2/sr/um

NWLR(673.5nm) didn’t
achieved the standard
accuracy on coastal regions.
→ Standard accuracy isachieved when in-situ data onlakes, which are not originallysubject to validation, areexcluded.

•NWLR(490nm, 530nm, 565nm) achieved the target accuracies, NWLR(380-443nm, 673.5nm)
achieved the standard accuracies.

•

Increased number of valid pixels [Version 2]: 110-596 points → [Version3]: 154-1005 points
Validation ResultRelease AccuracyStandard Accuracy

Target Accuracy[Ver. 2] 20-37%→[Ver. 3] 21-42%

60%(443-565 nm)

50% (≦600 nm)

30% (≦600 nm)[Ver. 2]0.542 →[Ver. 3] 0.497W/m2/sr/um

N/A

0.5W/m2/sr/um (>600 nm) 0.25W/m2/sr/um (>600 nm)
3Validation Results of Ocean NWLR Products:
Normalized Water-Leaving Radiance - ACP
Major Updates of Algorithm:
••
•
•
•

Added water leaving reflectance estimation model in the red(VN07) and near-infrared(VN10)
bands using Linear combination index (LCI)
Applied the vicarious calibration
Improved sunglint correction method
Added negative NWLR correction
Described correction formula for TAUA_670 and TAUA_865 in HDF attributes

Validation Method:
Validated the accuracies of predicted aerosol optical thickness at 865nm(Taua_865) from theSGLI algorithm comparing with in-situ data of AERONET-OC and AERONET Maritime
Aerosol Network (MAN)

Quality Control:••

In-situ data: time difference in ±3 hours to SGLI observation
SGLI data: average of the data passed the following conditions within a 5 by 5 pixel
centered the in-situ point (for details refer to Bailey et al, 2006)
1. 13 or more pixels which satisfies the following conditions: aerosol opticalthickness < 0.5, solar zenith angle < 70 degrees, NWLR of all channels > 0,
CLDAFFCTD, GAMMMA-OUT and OVERITER flags aren’t set.
2. Coefficient of variation for TAUA_865 less than 0.05

Period of Validation:•January 1, 2018 - March 31, 2021
4

Validation Results of Ocean NWLR Products:
Normalized Water-Leaving Radiance - ACPTAUA_865

TAUA_865_corrected

Achieved Release
AccuracyAcieved StandardAccuracy

N=530
Accuracy 62.3%

N=530
Accuracy 46.9%

There is a positive bias because the aerosol model used in the atmospheric correction is
optimized for NWLR not AOT estimation.
→ It is possible to obtain values closer to reality and achieve standard accuracy by applying
the correction formula.
Correction formula：TAUA_865_corrected = 0.822 * TAUA_865 + 0.0
Validation Result

Release AccuracyStandard Accuracy

Target Accuracy[Ver. 2] 65%(not corrected)[Ver. 3] 46%(corrected)

80% (AOT@865)

50% (AOT@865)

30% (AOT@865)

Achieved Standard Accuracy

5Photosynthetically available radiation
Daily RMS/AVG=19%

8-day RMS/AVG=14%Monthly RMS/AVG=8.9%

Yearly RMS/AVG=6.4%

Bias for each buoy：dependency seems small•••

Daily PAR is estimated by instantaneous transmittance from visible channels.
Reference PAR is made from daily SWR observed by buoy, PAR/SWR ration estimated by
Pstar-4 calculation and objective analysis water vapor data
Achieved the target accuracy（No change from ver.2）

Validation result

Release accuracyStandard accuracy

Target accuracy[Ver.2] 9.5%→[Ver.3] 8.9%

20% (10km/month)

15% (10km/month)

10% (10km/month)66

Validation Results of Ocean IWPR Products:
Chlorophyll-a Concentration - CHLAMajor Updates of Algorithm:•None of major updates

Validation Method:
Validated the accuracies of predicted CHLA data from the SGLI algorithm comparing within-situ data(High Performance Liquid Chromatography: HPLC or fluorescence method) ofship observation.

Quality Control:••

In-situ data: time difference in ±3 hours to SGLI observation
SGLI data: average of the data passed the following conditions within a 5 by 5 pixel
centered the in-situ point
1. 13 or more pixels which satisfies the following conditions: aerosol opticalthickness < 0.5, solar zenith angle < 70 degrees, NWLR of all channels > 0,
CLDAFFCTD flag isn’t set.

Period of Validation:•January 1, 2018 - May 31, 2022

7

Validation Results of Ocean IWPR Products:
Chlorophyll-a Concentration - CHLA
The coast of Japan (2021/05/10)
Ver.2

Ver.3

Valid pixel ratio
28%

Valid pixel ratio
38%

CHLA
Achv. Standard

N = 351
Accuracy：-59% ~ 141%
Valid pixel ratio= number of valid pixels/ number of total pixels••

Achieved Standard Accuracy
Increased the number of validation points on coastal and sunglint areas becauseof the improvement of NWLR estimation.

Validation Result

Release AccuracyStandard Accuracy

Target Accuracy[Ver. 2] -60~148%→[Ver. 3] -59~141%-60%~+150%(offshore)-60%~+150%-35%~+50%(offshore)-50%~+100%(coastal)8

Validation Results of Ocean IWPR Products:
Colored Dissolved Organic Matter - CDOM
Major Updates of Algorithm:•None of major updates

Validation Method:
Validated the accuracies of predicted CDOM data from the SGLI algorithm comparing within-situ data of ship observation.

Quality Control:••

In-situ data: time difference in ±3 hours to SGLI observation
SGLI data: average of the data passed the following conditions within a 5 by 5 pixel
centered the in-situ point
1. 13 or more pixels which satisfies the following conditions: aerosol optical
thickness < 0.5, solar zenith angle < 70 degrees, NWLR of all channels > 0,
CLDAFFCTD flag isn’t set.

Period of Validation:•January 1, 2018 - May 31, 2022

9Validation Results of Ocean IWPR Products:
Colored Dissolved Organic Matter - CDOM
CDOM [ver.3]

・Ariake・Hokkaido
・Ise-Mikawa
・ECS・Iwate・Sagami

N=52Accuracy:-69% ~ 223%

In-situ aCDOM(412nm) (/m)••

Achv. Standard

SGLI aCDOM(412nm) (/m)

SGLI aCDOM(412nm) (/m)

CDOM [ver.2](参考)・Ariake・Hokkaido
・Ise-Mikawa
・ECS・Iwate・Sagami

N=67
Accuracy:-60% ~ 149%
In-situ aCDOM(412nm) (/m)

Achieved Standard Accuracy
Increased the number of validation points on coastal and sunglint areas becauseof the improvement of NWLR estimation.

Validation Result

Release AccuracyStandard Accuracy

Target Accuracy[Ver. 2] -69~223%→[Ver. 3] -60~149%-60%~+150%(offshore)-60%~+150%-50%~+100%
10Validation Results of Ocean IWPR Products:
Total Suspended Matter - TSM
Major Updates of Algorithm:•None of major updates

Validation Method:
Validated the accuracies of predicted TSM data from the SGLI algorithm comparing with insitu data of ship observation.

Quality Control:••In-situ data: time difference in ±3 hours to SGLI observation
SGLI data: average of the data passed the following conditions within a 5 by 5 pixel
centered the in-situ point
1. 13 or more pixels which satisfies the following conditions: aerosol optical
thickness < 0.5, solar zenith angle < 70 degrees, NWLR of all channels > 0,
CLDAFFCTD flag isn’t set.

Period of Validation:•January 1, 2018 - May 31, 2022

11

Validation Results of Ocean IWPR Products:
Total Suspended Matter - TSM
Achieved Standard
Accuracy

Not Achieved
Standard Accuracy

・Ariake・English Channel
・Ise-Mikawa
・ECSin-situ data
quality control

SGLI TSM (g/m^3)

SGLI TSM (g/m^3)

・Ariake・English Channel
・Ise-Mikawa
・ECS

N = 71
Accuracy: -74% ~ 284%

N = 64
Accuracy: -59% ~ 145%

In-situ TSM (g/m^3)

In-situ TSM(g/m^3)

Standard accuracy is achieved except when there are errors in in-situ data or when theTSM concentration is particularly high, as on the English Channel.
(See appendix for details on quality control.)
Validation Result

Release AccuracyStandard Accuracy

Target Accuracy[Ver. 2] -71~242%→[Ver. 3] -59~145%-60%~+150%(offshore)-60%~+150%-50%~+100%
12Validation Results of Ocean SST Products:
Sea Surface Temperature - SST
Major Updates of Algorithm:•••

Introduction of atmospheric optical thickness climatology to improve atmospheric correction.
Cloud mask method:
1. Improvements by introduction of 1.6 micron data and so on (Daytime) and
2. Readjustment of thresholds for each quality level (Nighttime).
Introduction of a preprocessing to reduce stripes and random noise in L1B data.

Validation Method:
SGLI SST Version 3 was validated by comparing SGLI SSTs with in-situ SSTs.

Quality Control:•In-situ data: Moored and drifting buoys data provided by NOAA/iQuam (version 2.1).
The data were screened based on the QC result of the iQuam. High qualified
data (iquam flag = 0 and quality level = 5) were used for the validation.

• SGLI data: SGLI SST V3 of the 1-km spatial resolution with the quality assured as
good or acceptable: which are used to calculate L3 statistics. An SGLI SST
nearest to the center was chosen for each 1hr x 3km collocation window
centered on each buoy data and compared with the centered buoy data.

Period of Validation:•January 1, 2018 - December 31, 201913

Validation Results of Ocean SST Products:
Sea Surface Temperature - SST
SST (Daytime)

Improved cloud mask

SST (Nighttime)Ver. 2

Accuracy:
0.40℃

Accuracy:
0.43℃

Ver. 1••

Ver. 3The increased total number of valid pixels is due to theimproved cloud masking.
Cloud contaminations have been improved at night due toadjusted thresholds.

Ver. 2Modified cloud masking has also
improved cloud masks at and around SST
fronts during the daytime.

Validation Result

Release AccuracyStandard Accuracy

Target Accuracy

0.4(V2) → 0.4℃ (daytime)
0.7(V2) → 0.4℃ (nighttime)

0.8℃ (日中)

0.8℃

0.6℃

Achieved Target Accuracy
14Appendix

15

Validation Results of Ocean IWPR Products:
Total Suspended Matter - TSM
TSM validation results color-coded by sea area.

Distribution of in-situ TSM by sea area
（ All data, including non-matchup data ）MaxThe sea around Japan
Mean：8.68
Std div：9.15

thirdquartile

outlier

40 g/m3

Median40 g/m3

firstquartile
Min※The outlier is the value that is more than 1.5 times thequartile range away from the first and third quartiles.

 TSM on the English Channel in spring are extremely high and rarely exceed 40 g/m3
on the sea around Japan.
 In this validation, in-situ data of TSM > 40g/m3 is removed.

Validation Results of Ocean IWPR Products:
Total Suspended Matter - TSM(B) in-situ TSM vs. TSM
estimated from in-situ Rrs
TSM from in-situ Rrs (g/m3)

SGLI TSM (g/m3)(A) in-situ TSM vs. SGLI TSM

TargetIn-situ TSM (g/m3)(C) Rrs comparison of thetarget point

SGLI

565 nmTable 1:Comparison of estimated andin-situ values for TSM and Chl-a
TSM (g/m3)

Target•In-situ TSM (g/m3)(D) Water sampling points
on the same day•

Ise Bay
TSM [g/m3]

490 nmin-situTargetChl-a(mg/m3)

in-situ

0.28

36.55

SGLI

7.11

15.85

Estimation error of Rrs (NWLR) is unlikely
to be the cause of outlier of TSM estimate
at the target point :➢ TSM estimation from in-situ Rrs at
the TSM sampling point is far off(Figure B).
➢ Rrs at 490 nm and 565 nm, which arenecessary for TSM estimation, areclose to in-situ Rrs (Figure C).
High possibility of measurement error inin-situ TSM :➢ TSM at the near stations on thesame day (Figure D) varied from 2
to 5 g/m3 , but Chl-a was similar at
21 to 44 mg/m3.
➢ TSM value is too small for Chl-a(Table 1)

Removed as an outlier in this validation