3. GLI Ocean algorithms
Operation flow Full resolution

1-km Resolution

H. Fukushima
OTSK1aLevel1B
1BLevel

CLFLG
CLFLG
S. Ackerman
K. Stamnes

R. Frouin

OTSK2/5/6/7

B.G. Mitchell,
M. Kishino
OTSK13

H. Kawamura

NL_FR
FR
NL_

L2 Mapping

L2Map
L2Map
QF_OC
QF_OC
L2Map
L2Map
LA
LA
L2Map
L2Map
NW
NW

CS_FR
CS_FR

ST_FR
ST_FR

L2Map
L2Map
ST
ST
L2Map
L2Map
QF_ST
QF_ST

L2Map
L2Map
CHLA
CHLA
L2Map
L2Map
CDOM
L2Map
CDOM
L2Map
K490
L2Map
K490
L2Map
SS
SS4-km resampling

1600×1600 km scene

Near real time operation
1at direct receiving station

3. GLI Ocean algorithms (conti.)
Operation flow Low resolution
Almost same as full-resolution processing

4-km resampling

OTSK1a
L2A_OA
L2A_OAOTSK2/5/6/7
OTSK134-km pathL3binNW
NW
L3bin

NL_LR
NL_LR
CS_LR
CS_LR

ST_LR
ST_LR

L3 space bin

L3 time bin (Daily, 8-day, Monthly)
L3binLALA
L3bin

L3binCSCS
L3bin

L3 Statistical Mapping

L3binSTST
L3bin

9-km equal area

L3STAMap
L3STAMap
L3STAMap
L3STAMap
L3STAMap L3STAMapL3STAMap
L3STAMap
L3STAMap
CHLA
ST
L3STAMap
L3STAMap
CHLA
ST
NW
LA
L3STAMap
NW
LA
L3STAMapCDOM
SS L3STAMap
CDOM
SS
9-km global map
K490
24-km Resolution
K490

3. Algorithm (basic flow ofOTSK1awith band switch)
Lt at 380-710nm

GLI observed Lt at 749CH16, 865CH18, 678CH13, 865’CH19 nm.. Ratio1 and Ratio2 calculated by Lt749 and Lt865
Lt→ρt .. convert to reflectanceρa+ρma=ρt−ρm .. subtract molecular reflectanceLt→ρt :convert to reflectanceρa+ρma+ρw=ρt−ρm:subtract molecular reflectance.. look up table of ρa+ρma→ta at 749, 865, 678, 865’ of M
τa(865CH18), τa(865’CH19).. Convert by K-extension of model M

τa(749CH13)
Ratio1τa(749)τa(865CH19)
Ratio2
τa(865).. composed by Ratio1 and Ratio2.. aerosol model selection by ε749/865 at M1~9τa(865) at Mselect.. convert by K-extension of the selected model Mselectτa at in-water channels 380-710nm.. look up table of τa→ρρa+ρma of Mselectρa+ρma at in-water channels

for models M= 1 to 9

τa(749CH16), τa(678CH13)−(ρa+ρma)

ρw at 380-710nm
LwnLw at 380-710nm
33. Algorithm (characteristics ofOTSK1a)•Principal investigator is Prof. H. Fukushima same as OCTS.
•Atmospheric correction by 749nm and 865nm bands (except forband-saturated area)•Look Up Table (τa←(aerosol model)→ρa+ρma) is calculated by
RSTAR-5b (PSTAR) developed by Prof. Nakajima of CCSR
Tokyo Univ.
The next version will include functions of•Sunglint correction developed by Prof. H. Fukushima•Whitecap correction developed by Dr. R. Frouin of SIO•Iteration for non-zero Lw using in-water algorithm developed by
Tanaka-Toratani•Band switching to avoid NIR band saturation
4

3. Algorithm
Formulations of the GLI in-water empirical algorithms
VariableAlgorithm source

TypeCHLA

OC4-GLI by Mitchelland Kahru
Modified from
O’Reilly et al., 1998

Max Band Ratio,
Modified Cubic
Polynomial

GLI-K490
Modified from
Mitchell and Kahru,
1998

Cubic polynomial
in log-log

In preparation by
Mitchell and Kahru

Linear band ratio
in log-log

K490

CDOM

OTSK2/5/6/7

Equation, Coefficients (a*), Band Ratio (R)CHLA = 10 (a0 + a1×R + a2×R^2 + a3×R^3) +a4
R = log10(NWLR443 > NWLR460 > NWLR520) /NLWR545)
K490 = 10 (a0 + a1×R + a2×R^2+ a3×R^3)
R = log10(NWLR460/NLWR545)
CDOM440 = 10 (a0 + a1×R)
R = log10(NWLR443/NLWR520)

SS

Provided by Kishino,
May, 2002

Squarepolynomial inlog-log

SS=10(a0 +a1×R+a2×R^2)
R=log10(NWLR443/NWLR545)

RED TIDE
flag

Renewed
Kahru and Mitchell,
1998

Threshold ofband ratio

REDTIDE index on, if R < a0 and CHLA > a1
R = NWLR380/NLWR412
5

3. Algorithm
GLI SST algorithms

OTSK13

Atmospheric correction for SST

SST = a T35 + b (T35-T36) + c (T35-T34) + d (T35-T36)(1-1/cosθθs) + e (T35-T34)(1-1/cosθθs) + f

where T34, T35 and T36 are brightness
temperatures of bands-34, -35 and -36, θs isthe satellite zenith angle, a, b, c, d, e, and f
are constant coefficients; the coefficients indaytime may differ from those in nighttime.
After starting of GLI operation, the matchup data set will be used to adjust thecoefficients (a, b, c, d, e, f) of the equation.

GLI SST algorithm(OTSK13) is based on thesplit-window MCSSTtechnique.
From algorithm description by H.
6
Kawamura

3. Algorithm
GLI SST algorithms

OTSK13Cloud detection for SST

The framework of the clouddetection algorithm is to apply up
to some threshold tests to detectcloud, and then to identify a pixel
as cloud-free only when all thetests prove negative.

Coefficients of the threshold tests and thenumber of the tests will be determined using
the real GLI data after the ADEOS-II launch.

7

3. Algorithm
GLI Level 3 binning schemesbin 5940422

North Polerow 2160

L3 space/time bin
1/12°

Grid definition
Equal area grid same as
OCTS and SeaWiFS

bin

hsize=360°/Nrow
Nrow=int(4320×cosφ+0.5)(φ: Latitude of bin)bin
Equator−180°

Each bin is place along latitude line. Bin heightis 1/12° in everywhere. But bin width depends
on its latitude, which is considered as the areaof each bin is equal. The bin is numbered from−180° longitude to eastbound, and from south
to north.

row 1bin 1South Pole8

3. Algorithm
GLI Level 3 binning schemes

L3 space/time binequation

valuablechla,log-schemecdom,
N BIN ⋅ N BIN 
 ∑ log(Datai )
∑ss, k490
BIN  i =1, N BINlog( Ave) =nLw**, La**,( NBIN )BIN∑
BIN
Tau_865,
Same as OCTS
alpha_78
BIN

linear-scheme

sst



N BIN ⋅ N BIN  ∑ Datai ∑
BIN  i =1, N BIN
 BINAve = ∑ N BIN BIN(BIN)

Same as SeaWiFS
9