174
empirical absorption value and leaves room for other absorbers, supposedly detritus. It is also
possible that absorption by algae (at 415 and 440 nm) has been underestimated (by 50-70 %
1) in these waters, where small species are dominant (cf. remark concerning a* in Sargasso
Sea).
The above absorption budget is tentative and rests heavily on the validity of the Cole
expression. Refinements are possible as soon as more information becomes available with to
the rapid development of analytical approaches. The main conclusions, however, concerning
the relative role of the compartments and the dominance of algae in the absorption process
will probably be globally maintained.
Scattering coefficient of oceanic waters
By virtue of the additivity principle, equations similar to Eq. 14 and 15 can be written for b,
the scattering coefficient resulting from the presence of various particulate materials in
suspension:
(21)
and
b -b*
a
(22)
where b* is the ChI-specific scattering of algae and the subscripts (a, h, d) have the same
meaning as before. By following the same scheme as for absorption, it must first be
determined what information is available to complete the analytical expression 21, and then
examine if the cumulated contributions of the various components are compatible with the
global and empirical expressions, as previously derived from field data. This study has been
presented in detail elsewhere (Morel and Ahn, 1991) and only the main results are given
below.
empirical absorption value and leaves room for other absorbers, supposedly detritus. It is also
possible that absorption by algae (at 415 and 440 nm) has been underestimated (by 50-70 %
1) in these waters, where small species are dominant (cf. remark concerning a* in Sargasso
Sea).
The above absorption budget is tentative and rests heavily on the validity of the Cole
expression. Refinements are possible as soon as more information becomes available with to
the rapid development of analytical approaches. The main conclusions, however, concerning
the relative role of the compartments and the dominance of algae in the absorption process
will probably be globally maintained.
Scattering coefficient of oceanic waters
By virtue of the additivity principle, equations similar to Eq. 14 and 15 can be written for b,
the scattering coefficient resulting from the presence of various particulate materials in
suspension:
(21)
and
b -b*
a
(22)
where b* is the ChI-specific scattering of algae and the subscripts (a, h, d) have the same
meaning as before. By following the same scheme as for absorption, it must first be
determined what information is available to complete the analytical expression 21, and then
examine if the cumulated contributions of the various components are compatible with the
global and empirical expressions, as previously derived from field data. This study has been
presented in detail elsewhere (Morel and Ahn, 1991) and only the main results are given
below.