ribution
inked to
ist. The
In gulf
lons of
the year
-induced
S may be
ping to
ral ang
OWS) by
ait. In
eurs and
ncluding
“ease in
l mixing
nwelling
ar to be
pigment
10ut the
limited
Esquiman
d-driven
nposites
tions in
ble 1).
chat the
d during
viously.
rophyll-
stly by
pigment
ge-scale
se areas
ist and
las than
-3
mg m i
erage
© Lo Oo
= on Lam
values,
n being
ly, 1981
-ions of
hwestern
ed and
981.
of the
to some
ty EF
et al
1982). Other regions with high pigment concen-
trations can also be associated with known
areas of upwelling, or areas influenced by
intense tidal mixing (mouth of the Saguenay
river, the western part of Jacques-Cartier
strait, Northumberland and Belle-Isle straits,
and the Magdalen Shallows). Therefore,
interannual changes in freshwater output and
wind forcing are the ‘most likely factors
governing the observed variability.
4. CONCLUSION
Remote sensing using the CZCS has allowed us
to make important new observations regarding
phytoplankton distribution in. the- CsL,
including the presence of an automnal bloom
that has not been previously described. In
addition, our study suggests that interannual
variations in the concentration and
distribution of pigment biomass could be
higher than seasonal changes. The mean pigment
concentration in the GSL was 25% higher in
1980 than in 1979 and 38% than in 1931. The
area covered by high pigment concentration was
also greater during 1980. Knowledge gained
during this project, using a limited number of
images, will be much more valuable when long
time series measurements become available from
the SeaWiFS and MODIS sensors.
ACKNOWLEDGEMENTS
This work was partially supported by
Universidad Nacional Autónoma de México,
Department of Fisheries and Oceans (Canada),
Université du Québec à Rimouski and Québec
Government grants to C.F.Y. during his Ph. D.
studies. The authors thank Drs V. G.
Koutitonsky and J.-C. Therriault for providing
in situ data and for constructive comments
during the study. Laure Devine-castonguay
helped improving the text.
REFERENCES
Arnone R.A. and P.E.. LaViolette, 1984. A
method of selecting optimal Angstrom
Coefficients to obtain quantitative ocean
color data from Nimbus-7 CZCS.
SPIE, Vol. 489, Ocean Optics VII,
Proceedings of
pp. 187-194.
Bugden G.L., B.T.Hargrave, M.M. Sinclair, C.L.
Tang, J.-C. Therriault and P.A. Yeats, 1982.
Freshwater runoff effects in the marine
environment: the Gulf of St. Lawrence example.
Canadian Tech. Rep.
Sciences 1078, 88 pp.
of Fisheries and Aquatic
de Lafontaine Y., S. Demers and J. Runge,
1993. Pelagic "food ‘web interaction‘ and
Productivity in the Gulf of St. Lawrence: A
Perspective. In: The Gulf of St. Lawrence:
small ocean or big estuary ?, J.-C. Therriault
(ed.), Canadian Special Publication of
E neris and Aquatic Sciences 113, pp. 99-
409
Eckstein B.A. and J.J. Simpson, 1991a. Cloud
Screening Coastal Zone Color Scanner images
using channel 5. Int. J. of Rem. Sens., 12,
pp. 2359-2377.
Eckstein B.A. and J.J. Simpson, 1991b. Aerosol
and Rayleigh radiance contributions to coastal
zone color scanner images. Int. J. of Rem.
Sens., 12, pp. 135-168.
Evans R.H. and H.R. Gordon, 1994. Coastal Zone
Color Scanner "system calibration": a retro-
spective examination. J. of Geophys. Res., 99,
pp. 7293-7307.
Fuentes-Yaco, C., P. Larouche, A. Vézina, C.
Vigneau and M. Gosselin, 1995. Catalogue of
phytoplankton pigment images from the Gulf of
St. Lawrence: Coastal Zone Color Scanner data
from 1979 to 1981. Can. Data Rep. Hydrogr.
Ocean Sci. 135, 91 pp.
Gordon H.R., J.W. Brown, O.B. Brown, R.H.
Evans and D.K. Clark, 1983a. Nimbus-7 CZCS:
reduction of its radiometric sensitivity with
time. Applied Optics, 22, pp. 3929-3931.
Gordon H.R., DK. Clark, Jd.W. Brown, O.B.:
Brown, R.H. Evans and W.W. Broenkow, 1983b.
Phytoplankton pigment concentrations in the
Middle Atlantic Bight: comparison of ship
determination and CZCS estimates. Applied
Optics, 22,.pp. 20-36.
Morel A. and J.F. Berthon. 1989. Surface
algal biomass profiles and potential
relation-
pigments,
production of the euphotic layer:
ships re-investigated in view of remote
sensing applications. Limnol. and Oceanogr.,
34, pp. 1545-1562.
Mueller J.L., 1988. Nimbus-7 CZCS: electronic
overshoot due to cloud reflectance. Applied
Optics, 27, pp. 438-440.
Simpson J.J., 1993. The coastal zone color
scanner (CZCS) algorithm. A critical review of
residual problems. In: Ocean color: theory and
applications in a decade of CZCS experience.
V. Barale and P. M. Schlittenhardt, editors,
Kluwer Academic Publishing, ECSC, EEC, EAEC,
Brussels and Luxemburg, pp. 117-166.
Sturm B., 1981. The atmospheric correction of
remotely sensed data and the quantitative
determination of suspended matter in marine
water surface layers. In: Remote sensing in
meteorology, oceanography and hydrology, A.P.
Cracknell, (editor), Ellis Hardwood Ltd.,
Chichester, pp. 163-197.
Williams- S.P., F-F. Szajna and—W.A. Hovis,
1985. Nimbus 7 Coastal Zone Color Scanner
(CZCS) Level 1 data product user's guide. NASA
Technical Memorandum 86203, 52 pp.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996
