ation
n the
ters.
ed at
* the
tional
going
and
nt of
is of
re for
| New
:RISS
rthern
rating
nation
levels
| 1999
langes
ogical
nment
essing
etland
ig the
etland
vill be
'estern
across
ar of
ig the
asonal
ever,
|
tistical
field
ropical
imetric
omass,
tc.) in
, et al,
stically
y site ,
rithms,
munity
In associated research at the same site the vegetation
structural changes identified by radar analysis were shown
to be significantly related to avian habitat quality (Imhoff
and Milne, 1995)
It is also becoming evident that in respect to tree
branching patterns, models developed on boreal-temperate
forests are not applicable to Australian flora. Work has
begun on developing a canopy model that takes into
account branch size and orientation as well as foliage
cover in an attempt to separate foliage or green biomass
from woody biomass in Northern Australian forests and
woodlands.
The ability to derive tree stand parameters directly from
SAR depends on the development of inversion models
that facilitate prediction based on radar scattering
characteristics alone (Dong, 1995). Correlative
relationships between floristic induced structural changes
and radar backscatter have been replicated in a modelled
environment using wavelet transform techniques to
suppress speckle noise and segmentation routines based
on a Gaussian Markov Random Field Model (Dong et al.,
1998)
This approach is currently being trialled in Kakadu
National Park to test its ability to identify and classify like
forest stands. If successful, these procedures stand to
make a major contribution to the way SAR data is
processed to derive geophysical information. Evaluation
of a knowledge based classification technique that uses
multi-frequency SAR to segment an image into different
classes is being undertaken concurrently.
CONCLUSION
Wetlands are unique, diverse and valuable habitats for
supporting aquatic and terrestrial life forms. They are
areas of high conservation value and worldwide contribute
significantly to global biogeochemical functioning.
The study is innovative in that it attempts to relate radar
backscatter to specific biophysical and environmental
parameters. As seasonal change brings different soil-
boundary-plant conditions, so backscatter can be expected
to change. The objective of this study is to take measured
environmental changes and relate these to received
backscatter.
The eventual ability to monitor and link diurnal, seasonal
and episodic changes in biogeochemical properties to
calibrated backscatter returns, provides the potential for
radar to make a major input into the modelling of long
term environmental change and to contributing to our
knowledge of global processes.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budapest, 1998
SELECTED REFERENCES
Ahmed, Z., 1991. Radar backscatter modelling of
forested regions containing arbitrarily oriented woody
structures, unpublished PhD thesis, The University of
New South Wales, 193pp.
Australian Water Resources Council, 1976. Review of
Australia's Water Resources (1975). Australian
Government Publishing Service, Canberra, 170pp.
Dong, Y., 1995. A Long Wavelength Radar Backscatter
for Forests, unpublished PhD thesis, The University of
New south Wales, Sydney.
Dong, Y., Forster B.C., Milne A.K., and Morgan G.A.,
1998, Speckle suppression using recursive wavelet
transforms, International Journal of Remote Sensing,
19, 2, 317-330
Finlayson, C.M., Wilson B., Courie, I. Management of
Freshwater Monsoonal Wetlands in Donohue R., and
Phillips, B., (eds) Educating and Managing for Wetlands.
Proceedings of Wetland Conservation and Management
Workshop, February 1991, Newcastle, ANPWS,
Canberra. P109-116.
Finlayson, C.M., Vegetation Changes and Biomass on an
Australian Monsoonal Floodplain in Gopal, B., Hillbricht-
Ilkowska, A., and Wetzel, R.G., (eds), Wetlands and
Ecotones: Studies in Land-Water Interactions. National
Institute of Ecology, New Delhi, 1993. pp157-171.
Imhoff, M., Sisk, T., Milne, A., Morgan, G., 1997,
Remotely Sensed Indicators of Habitat Heterogeneity: The
use of SAR for mapping, Vegetation Structure and Bird
Habitat, Remote Sensing of Environment, 60, pp217-27.
Miine, A.K., Characterisation of Australian vegetation
types using ERS-1, SAR, 2nd ERS-1 Symposium,
October 1993, Hamburg. ESA SP-361, pp459-462.
Milne, AK. and Tapley, LJ., AIRSAR Deployment in
Australia, September 1993: Management and Objectives.
4th JPL Airborne Geoscience Workshop, Volume 3,
October 1993, JPL Publication 93026, Pasadena, pp37-40.
Richards, J.A., Woodgate, P.W. and Skidmore, AK.
1987. An explanation of enhanced radar backscattering
from flooded forests. International Journal of Remote
Sensing, 8(7), pp1093-1100.
Richards, J.A., Sun, G., and Simonett, D.S., 1987a. L-
band radar backscattering modelling of forest stands.
LE.E.E. Transactions on Geoscience and Remote Sensing,
GE-25(4), pp487-498.
Richards, J.A., and Ahmed, Z., 1988. Association of
radar backscatter with biophysical characteristics of
Australian forests. International Geoscience and Remote
Sensing Symposium '88. pp1363-1366.
547
