42
Landsat TM
In situ data
n
Y
f 090
X=k’ S S(A)*R(A)*x(A) d A
450
090
Y=k’ Î S(A)*R(A)*y(A) d A
450
090
Z=k’ J S(A)*R(A)*z(A) d A
450
090
k’=100/5 S ( A )* y ( A ) d A
450
f 7 80
X=k’ j S( A )*R( A )*x( A ) d A
380
780
Y=k’ SS(A)*R(A)*y(A) d A
3 80
7 80
Z=k’ S S ( A )*R( A )*z( A ) d A
380
7 80
.k’=l 00/ S S ( A )* y ( A ) d A
\ 3 8 0
X/(X+Y+Z)
(Hue, Value, Chroma)
:Y/(X + Y + Z)
1
(y, x, ;y)
A
1
1
!
a^|A < >Transp. |
Database-derived
Empirical model
4. Verification of the model and summary
Fig. 8 shows the comparison of the estimated and the observed transparency. Observation
time lag between the twos is less than 4 hours. The rms error is 67cm and is small enough
compared with the estimated maximum of 6meters.
The main points of this study is summarized as follows.
1) Color of sea database is developed and the model to estimate transparency is derived from the
database.
2) Atmospherically corrected Landsat TM data is applied to the model to estimate transparency
and rms error between the estimated and the observed is 67cm for the maximum estimated
transparency of 6meters.
3) It demonstrates the possibility of mapping not only vertical but also horizontal variabilities of
optical properties of Osaka Bay water based on Landsat TMdata.
References
1) Osaka prefectural fisheries experiment station : Annual activity report of Osaka prefectural
fisheries experiment station, lOOp, 1971.(original in Japanese).
2) Ota,N.: Colorimetric Engineering. 305pp. Tokyo Denki University, Tokyo, 1993.(original in
Japanese).
3) NASA Earth Science and Applications Division : The Highlights of 1989, 78p, 1989.
4) Chavez,P.S.: An Improved Dark-Object Subtraction Technique for Atmospheric Scattering
Correction to Multispectral Data, Remote Sensing of Environment, 24, 459-479, 1988.