and they do not grow more than 10 cm off the water surface.
Ne p Though in both bands they behave as smooth surfaces acting
aree as quasi-specular reflectors.
, 1994.
Relatório 7. CONCLUSIONS
)
Eso This study led to the following conclusions: 1) L band is not
z as good as C band for discriminating among the macrophyte
Ahern, F. © genus; 2) L band C composition is very useful for setting the
i Mapping N limits between open water and aquatic vegetation and aquatic
Brazilian 8 system and terrestrial system; 3 ) multiband composition
E allows to separate the macrophyte stands according to their
2 structural features rather than their biophysical features.
grated and
vironment Acknowledgments: The authors acknowledge the National
kne (ed.) Institute for Space Research, the Canadian Centre for
e Remote Sensing and the Canadian International
Development Agency for supporting this project. The authors
Microwave t 8 8 2 ££ 3 € 3 also acknowledge Dr. Raimundo Almeida Filho and the
)n- Wesley, 9 a = National Space Development Agency of Japan for providing
eid à the JERS-1 data used in this research.
Figure 5 - Normalized digital number of the various ground
classes (ech - eichhornia; scp- scirpus; tph - typha; pst- pistia; 8. BIBLIOGRAPHY
htr -heterogeneous; slv -salvinia; frt - forest; wtr -water).
Dotted line - C band; Continuous Line - I band, Abdon, M. M.; Meyer, M. Variagáo temporal de áreas
The average DN for the macrophyte stands, on the other hand, °P adas por macrófitas aquélicas flo feserv terio, de Tucuruí
are much higher in the C band than in the L band, except for — através de dados do satélite Landsat/TM. In: Simpósio
the Typha sp. stands. The higher L band DN values observed ^ Brasileiro de Sensoriamento Remoto, 6., Manaus, 24-29
in the Typha sp stands are related to the larger biomass and — jun.1990. Anais. Sáo José dos Campos, INPE, 1990, v.2, p.
height of this genus when compared to the others present in 545.548. (INPE-5174-PRE/1643), 1990.
the reservoir. The Ttypha sp. genus is characterized by 1 to 2 >
meter vertically oriented grass-like leaves organized in very Costa, M. P. F. The effect of airborne SAR-C
dense tufts. It is interesting to observe that the Typha average multipolarization and multiangle images in the backscattering
DN is even higher than that of the Forest, what suggests the qi . . 4i :
contribution of double bounce scattering between the tufts and ee of a P Tu ner ram Bein.
the underlying water. The same behavior can be observed in echnical Report, Ottawa, Canada, :
the C band. Costa, M.P. de F. ; Novo, E.M.L.M.; Noernberg, M.; Ahern,
In order to qualitatively explore the relationship between the AH j Pictsch. RW A of Aquatic Piants in ic
classes biophysical parameters and the DN in the L and C Brazilian Amazon using Multi-polarization C-Band SAR data.
band, table 2 was organized. 26 th International Symposium on Remote Sensing of
Environment, Vancouver, British Columbia, CA., March 25-
In table 2 the ground classes where ranked according biomass 29 1996.
and height, and the SAR bands according to DN value. The :
following can be observed: a) L band is more sensitive to the Dobson, M. C. Ulaby, F.T.; Pierce, L.E. Sharik, T. L.;
canopy background than to biophysical parameters since the Bergen, K. M.; Kellndorfer, J.; Kendra, J.R; Li, E.; Lin, Y.C.;
forest biomass and height is much larger than the typha ‘s. L Nashashibi, A.; Sarabamci, K.; Siqueira, P. Estimation of
band is not sensitive to changes in biomass among the : ; ve iB or i
macrophyte genus grouping together pistia and scirpus which forest biophysical characteristics in Northern Michigan with
have an average of 100 cm difference in height; b) C band also — SIR-C/X- SAR. IEEE Transactions On Geoscience And il
does not respond to changes in biomass and height, but much Remote Sensing. 33(4): 877-895, 1995.
more to canopy structure. The six different types of
macrophyte stands were better discriminated in the C band. Hess, L. L.; Melack, J.M.; Filoso, S.; Wang, Y. Delineation of
Inundated Area and Vegetation Along the Amazon Floodplain
Table 2 - Ranking of macrophyte biophysical features with the SIR-C Synthetic Aperture Radar. IEEE Transactions
on Geoscience and Remote Sensing, 33 (4): 896- 903, 1995.
Ground Class Biomass and L band DN | C band ;
DN Holmes, M.G. Monitoring vegetation in the future: radar.
Forest Botanical Journal of the Linnean Society, 108 (93): 93 -109,
1992.
Eichhomnia Junk, W.J. ; Howard-Willians, C. Ecology of aquatic
macrophytes in Amazonia. In: (H. Sioli, ed. ). The Amazon ,
Pistia sp. Dr. W. Junk Publishers, Dordrecht, 1984.
Salvinia
Junk, W.J.; J.A.S. Mello Impactos ecológicos das represas
Eichhornia sp. shows the first and the second hi gher DN in the hidrelétricas na bacia amazónica brasileira. Estudos
L ng C band, respectively. Eichhornia sp. is densely Avangados 4 (8): 127-143, 1990.
ouibuted reaching a height of 30 cm. It has randomly Kelman, J. - Risk analysis for design in the Amazon basin.
oriented cup-shaped leaves 10 to 15 cm large. As a ;
consequence of this dossel structure, volume A seems Hydrology and Water Management of the Amazon Basin.
to be the primary scattering mechanism being responsible for ABRH/IWRA, Manaus, aug, 5-9, 1990.
the high DN values in both bands. Pistia d Salvini
; sp. and Salvinia sp. , , ,
show the lowest DN in both bands. oy have sll leves Lopes, A. ; Nezry, E. ;Touzi, R. ; Laur , H. Structure detection
195
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996
