n are 
he east 
r the 
a were 
he 
und in 
‘the 
e solar 
ould be 
tigat- 
values 
nnel of 
spectral 
1 
algor- 
he value 
Id b in 
(5) 
iA. The 
iE This 
on the 
rence 
nt. 
; used 
results 
LC 
or. 
lace and 
para- 
= 
uncertainty in the chlorophyll concentrations for a certain range of variation 
in these parameters. If we assume that the salinity of the sea-water generally 
lies in the range of 25% to 40% and the temperature of the sea-water may 
change by as much as 20?C then we find that the uncertainty in the chlorophyll 
concentration is about 2% 
Error Due to Different Values of n. 
  
Many investigators have quoted different values of the refractive index 
of sea-water. For example, Sturm (26) has used n = 1.341 whereas Larsen and 
Jéórgensen (27) have quoted a value of 1.33. This difference in the value of n 
introduces some error in the chlorophyll concentration which we find to be about 
596. 
CONCLUSIONS 
The inflight calibration quality of the CZCS detectors have changed sig- 
nificantly. The atmospheric correction algorithm is shown to underestimate the 
radiance ratio in Eon.(5) by about 11%. This could have a sizable effect on the 
water colour algorithm. It is shown that even 1% difference in the solar irrad- 
iance for the CZCS channel 1 results in a serious error in the chlorophyll-like 
pigment algorithm. It would seem to be valuable, in the future, to check atmos- 
pherically-corrected CZCS data with the results of simultaneous in-situ measure- 
ments of water-leaving radiance in the CZCS spectral bands; we are working on 
this problem. The error introduced due to the variations in the salinity and 
temperature is shown to be only about 2%. If one uses different values of the 
refractive index of sea-water then one introduces personal error. It is shown 
that a difference of 0.001 in the used values of the refractive index results in 
about 0.5% error. 
ACKNOWLEDGEMENTS 
I am grateful to Professor A.P. Cracknell for reading this manuscript. 
This work was supported by a grant from the Science and Engineering Research 
Council. 
REFERENCES 
1. Tyler, J.E., 1961, Proc. Nat. Acad. Sci., U.S., 47, 1726-33. 
2. Strickland, J.D.H., 1965, in Chemical Oceanoggraphy (J.P. Riley and 
G. Skirrow, Ed.), Vol.1, Academic Press, 577-510. 
3. Clarke, G.L., Ewing, G.C. and Lorenzen, C.J., 1970, Science, 167, 
1119-21. 
4, Gordon, H.R.,-1978, Appl. Opt., L7,-L631-6. 
5. Slater, P.N., 1980, Remote Sensing Optics and Optical Systems, Addison- 
Wesley Pub.Co. 
6. Sturm, B., 1981, in Remote Sensing in Meteorology, Oceanography and 
Hydrology, (A.P. Cracknell, Ed.), Ellis Horwood,. Chichester, 163-97. 
7. Cox, G. and Munk, W., 1954, J. Opt. Soc. Am., 44, 838-50. 
8. Fraser, R.S. and Walker, W.H., 1968, J. Opt. Soc. Am., 58, 636-44. 
9. Curran, R.J., 1972, Appl. Opt., 11, 1857-6686. 
10. Gordon, J.1., Harris, J.L. Sr. and Duntley, S.R., 1973, Appl. Opt., 12, 
1317-24. 
11. EURASEP Secretariat Newsletter, 1982, No.7. 
12. EURASEP Secretariat Newsletter, 1981, No.4. 
13, EURASEP Secretariat Newsletter, 1981, No.5. 
705