Backscattering from forest canopies over slanted terrain

Amar, F.; Fung, A.K.; Grandi, G. De; Lavalle, Carlo; Sieber, A.J.

doi:10.1109/igarss.1993.322266

Cited by 9 publications

(9 citation statements)

References 7 publications

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“…Such eVects were analysed recently using theoretical modelling simulations ( van Zyl 1993, Amar et al 1993 ) and/or experimental data ( van Zyl 1993, Luckman and Baker 1994, Holecz et al 1995. Terrain slope may have variable impacts on the backscatter as a function of: (i) SAR frequency, polarization and incidence angle, (ii) range of terrain slope and aspect angles, and (iii) type of forest and growth stage.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity of space-borne SAR data to forest parameters over sloping terrain. Theory and experiment

Castel¹,

Beaudoin²,

Stach³

et al. 2001

International Journal of Remote Sensing

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Recently, SAR data proved to be useful for the retrieval of forest biomass. However, the eVects of terrain slope must be addressed towards the generalization of biomass retrieval for varied forest and environmental conditions. To this aim, we developed experimental and theoretical approaches allowing the study of multi-frequency/multi-polarization forest backscatter of a given forest type, as a function of forest parameters and SAR local incidence angle over the relief. The experimental results showed that the sensitivity of SAR data to biomass was similar to that obtained over a at terrain, only if the backscatter data were calibrated for slope eVects. Moreover, the backscatter must also be corrected for its angular decrease, which can be removed using a simple angular model developed under assumptions of theoretical equations. The highest correlation of corrected backscatter with forest parameters related to aboveground biomass (such as stand age and bole volume) was achieved at L-HV 55°(R2=0.8 ) with results similar to those for at terrain. Modelling results validate the semiempirical model developed to remove the angular decrease of forest backscatter, which is due to variable optical depth with terrain slope. Results also indicated that the simple angular model may encounter problems for forested areas with low optical depth (t<0.5) located over extreme topographic conditions ( local incidence angle <10°or >80°).*

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Section: Introductionmentioning

confidence: 99%

Sensitivity of space-borne SAR data to forest parameters over sloping terrain. Theory and experiment

Castel¹,

Beaudoin²,

Stach³

et al. 2001

International Journal of Remote Sensing

View full text Add to dashboard Cite

show abstract

“…Surprisingly this result is valid for both forested and non-forested areas as long as the scattering surface is considered rough or rugged (Lee et al 2000). In the case of forested surfaces, the effect of terrain slope is dependent on frequency since it is the trunk-ground scatter and direct ground scatter that will affect the results (Amar et al 1993). Trees on slanted terrain continue to grow vertically (that is, along the plumb line) and since C-band scatter dominantly arises from the canopy, no difference is observed compared to a flat-terrain case (Amar et al 1993).…”

Section: Introductionmentioning

confidence: 92%

“…Historically, SAR researchers have held a pessimistic view as to the value of C-band SAR for forest applications , Amar et al 1993, Saatchi and Moghaddam 2000. The reason is that C-band radiation does not penetrate as far into the forest canopy as the longer-wavelength L-and P-bands (Israelsson and Sylvander 1992).…”

Section: Introductionmentioning

confidence: 99%

“…In the case of forested surfaces, the effect of terrain slope is dependent on frequency since it is the trunk-ground scatter and direct ground scatter that will affect the results (Amar et al 1993). Trees on slanted terrain continue to grow vertically (that is, along the plumb line) and since C-band scatter dominantly arises from the canopy, no difference is observed compared to a flat-terrain case (Amar et al 1993). For non-forested rough terrain, the C-band SAR signal is more sensitive to small scatterers in the resolution cell and this effect overwhelms that of the slanted terrain slope (Lee et al 2000).…”

Section: Introductionmentioning

confidence: 99%

“…In addition to providing more information about the forest canopy, C-band radar is also less sensitive than L-and P-band to variations in s 0 caused by slanted terrain (Amar et al 1993, Lee et al 2000. Surprisingly this result is valid for both forested and non-forested areas as long as the scattering surface is considered rough or rugged (Lee et al 2000).…”

Section: Introductionmentioning

confidence: 99%

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