Radar polarimetry and interferometry for remote sensing of boreal forest (original) (raw)
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L-band Polarimetric Interferometry in Boreal Forest Parameter Estimation, a Case Study
2006 IEEE International Symposium on Geoscience and Remote Sensing, 2006
In this study we concentrate on the application and validation of forest height estimation by polarimetric SAR interferometry for boreal forest. The study material was collected during the FinnSAR campaign, carried out in Finland in Fall 2003. The main instruments of the campaign were E-SAR airborne radar (L-and X-band) and HUTSCAT helicopter-borne profiling scatterometer (X-and C-band). The validated forest height estimation algorithm is based on Random Volume over Ground (RVoG) model inversion by using POLinSAR data. We compare POLinSAR-derived forest height with results from profiling HUTSCAT scatterometer measurements and with ground measurements and discuss the results. Our results show that the forest height values, estimated by means of two different instruments, are in good agreement.
Synthetic aperture radar polarimetry for forestry applica-tions
tudelft.nl
Imaging synthetic aperture radar polarimetry is one of the most exciting recent developments in high resolution remote sensing. This paper outlines the usage of this technique with reference to forest mapping and management. The methodology will be outlined and a description will be made of an application using airborne polarimetric SAR data from a Swedish coniferous forest. Results from this study are presented.
Polarimetric Interferometry in Forestry Applications: A Review
In this paper we review of recent developments in the use of Polarimetric Radar Interferometry for tree height estimation and ground topography mapping. We first motivate the subject by demonstrating the importance of tree height in the remote sensing of global vegetation cover and biomass. We then summarise the main aspects of the technique, outline the use of a 2-layer coherence model widely used for data inversion and show data validations from three important forest test sites; Oberpfaffenhofen and Fichtelgebirde in Germany and Glen Affric in Scotland. We conclude with an assessment of the potential future applications of this technology.
2016 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), 2016
This paper describes BorealScat, a tower-based radar campaign for acquiring multitemporal polarimetric, tomographic and Doppler radar measurements at P-, Land C-band over a hemi-boreal forest site in Remningstorp, Sweden. The facility consists of a 50-m high tower equipped with a radar system including an array of 30 antennas. The site will also be equipped with meteorological instruments and moisture sensors. The aim of the experiment is the temporal survey of radar signatures over time scales ranging from sub-seconds to years in varying environmental conditions. This experiment will provide fundamental information about the electromagnetic scattering mechanisms in boreal forests at P-, Land C-band.
International Journal of Remote Sensing, 2002
Airborne polarimetric Synthetic Aperture Radar (SAR) is used for estimating stem volume of a Finnish boreal forest by comparing different empirical models. Its capability for retrieval of snow water equivalent is then explored. Fully polarimetric Land C-band data were acquired over a Finnish test site in March and May 1995. The information content was explored qualitatively by inspecting polarimetric colour composites, and by applying decomposition algorithms to the polarimetric covariance matrices at individual frequencies. Three families of quantitative models were fitted to estimate stem volume: 1) F1P1 models, using a single frequency and a single polarisation; 2) F2P1 models, using the difference between HV polarisation at C-and L-band related to stem volume; 3) F1P4 models, based on a single frequency and the full polarimetric information, selected by stepwise multiple regression with stem volume; Stem volume estimates from SAR are compared with digital stem volume data by the Finnish Forest Research Institute. Prior information about the stem volume distribution addresses the saturation problem of the microwave response. The L-band F1P4 models in March and May 1995 have the smallest root mean square (rms) errors, around 22 m 3 /ha. Three multiple regression models to retrieve snow water equivalent from backscatter are presented: 1) EU model, an explorative, uncorrected multiple regression model; 2) EC model, an explorative, stem volume corrected multiple regression model; 3) CC model, a statistically conservative, stem volume corrected multiple regression model. The accuracy of snow water equivalent estimates was improved significantly by a simple linear correction for stem volume. The statistically conservative CC model showed that only L-band in HH polarisation explained a significant (P<0.05) proportion of snow water equivalent (r 2 =0.51). The explorative EC model resulted in r 2 =0.68 (P>0.05). Conclusions are: 1) Decomposition algorithms of the polarimetric covariance matrix result in information on scattering mechanisms in the vegetation canopy and on the ground, so being potentially of great value for land cover mapping; 2) Satellite polarimetric SARs, for example those to be flown on Envisat and ALOS, will be able to estimate stem volume on continental and global scales; 3) L-band SAR has a potential for snow cover mapping and runoff prediction.
Polarimetric SAR Interferometry For Forest Structure Parameter Estimation: Potential and Limitations
Hermetic reciprocating compressor with elliptical shell radiates noise whose frequency spectrum has a peak level at about 200 Hz and about 300 Hz. The 200 Hz and 300 Hz noise is mainly radiated from the top and the side of the compressor shell, respectively. For clarifying the noise radiation mechanism, experimental and theoretical analyses were performed. A noise source simulation test was set up where a speaker (driver unit) , connected to a compressor suction pipe, was driven by a white noise oscillator, and transfer function was measured by using four microphones. These tests clarified that the noise is cavity resonance in the compressor shell. By simulating a compressor mechanism and a shell to an annular cavity, resonance frequency can be calculated and it was clarified that 200 Hz and 300 Hz are cavity resonant frequencies in vertical derection and radius direction of compressor,respectivel~ By investigating the source using a compressor with some pressure and vibration acceleration transducers, it was clarified that the source is suction pressure pulsation in the compressor shell.
Forest Height Estimates for Boreal Forest using L-and X-band POLinSAR and HUTSCAT Scatterometer
In this paper we present a airborne polarimetric interferometric SAR measurement campaign, carried out in Finland in 2003. The main aim of the FinSAR campaign was to validate POLinSAR tree height retrieval algorithms for boreal forest and it was arranged jointly by Helsinki University of Technology (TKK) and German Aerospace Center (DLR) Microwaves and Radar Institute. During the campaign airborne DLR's E-SAR radar (operating at L-and X-band) and TKK's HUTSCAT scatterometer (operating at X-and C-band) were operated over a boreal forest test site to retrieve tree height. The tree height from fully polarimetric L-band SAR data was retrieved by Random Volume over Ground inversion and it was compared with scatterometer measurements and forest stand wise inventory tree height values. Additionally we calculated tree height from X-band single polarisation interferometric images by means of restricted RVoG model inversion and compared the results with other data. Our results show that the tree height values, estimated by means of two different radar instruments, are in good agreement. We also found that single band X-band data allows to calculate the mean tree height with surprisingly good accuracy.
Estimation and Monitoring of Tropical Forest Biomass Using Polarimetric Interferometric SAR Data
The purpose of the proposed work is to examine the feasibility of using Polarimetric Interferometric SAR (PolInSAR) techniques on ALOS PALSAR data to extract forest canopy heights with the ultimate objective of deriving biomass estimates. Previous work [1] has shown that in homogeneous European forest stands, tree height is a reasonably robust estimator of biomass through a simple allometric relationship. Moreover PolInSAR has proven itself as a valuable technology for tree height estimation at L-Band frequencies. The RVoG model (Random Volume over Ground) proposed in and elaborated in [3], permits a separation of ground and canopy scattering components of the interferometric phase. Through model inversion, the canopy height can be derived . Additionally, the bare earth elevation beneath canopy can also be recovered at least in airborne repeat-pass cases where temporal de-correlation is not prohibitive. While the PolInSAR results to date from airborne repeat-pass L-Band campaigns have been impressive, it is not clear to what extent it will be possible to derive similar results from ALOS data, owing to the much longer temporal baseline between acquisitions.