| 1. |
- Eriksson, Leif, 1970, et al.
(author)
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ALOS PALSAR calibration and validation activities in Sweden
- 2008
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In: Proceedings of The First Joint PI Symposium of ALOS Data Nodes for ALOS Science Program in Kyoto, Kyoto, Japan, 19 - 23 November, 2007. - 1349-113X. - 9784906653041 ; JAXA-SP-07-012
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Conference paper (other academic/artistic)
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| 2. |
- Eriksson, Leif, 1970, et al.
(author)
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ALOS PALSAR Calibration and Validation Results from Sweden
- 2007
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In: IEEE Geoscience and Remote Sensing Symposium (IGARSS 2007), Barcelona, Spain, July 23-27, 2007. ; DOI: 10.1109/IGARSS.2007.4423115, s. 1589-1592
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Conference paper (other academic/artistic)abstract
- In 2006 calibration activities for ALOS PALSAR wereconducted in Sweden. Four five-metre trihedral corner reflectorsand three smaller dihedral reflectors were deployed and operatedduring eight months. 23 PALSAR scenes were acquired over thecalibration site allowing an evaluation of the quality and temporalstability of the data. Results show that the co-polarized datahave been stable during the whole calibration period with variationsin the trihedral responses lower than 0.7 dB. The measuredresolution in azimuth was 4.4 m and in slant range 4.7 m forsingle polarization images and 9.5 m for polarimetric data. Forthe cross-polarized data large variations in the dihedral responseswere found. It is assumed that this is caused by a larger sensitivityto pointing errors. For the polarimetric data, estimation ofFaraday rotation gave values ranging from 0.1º to 3º.
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| 3. |
- Eriksson, Leif, 1970, et al.
(author)
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Stem volume estimation for boreal forest using ALOS PALSAR
- 2007
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In: 5th International Symposium on Retrieval of Bio- and Geophysical Parameters from SAR Data for Land Applications, Bari, Italy, September 25-28, 2007, ESA, Istituto di Studi sui Sistemi Intelligenti per l´Automazione. ; , s. CD-
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Conference paper (other academic/artistic)abstract
- An evaluation of ALOS PALSAR data for standwise forest stem volume estimation has been performed at a Swedish test site. The site is dominated by coniferous tree species. SAR data from three operational PALSAR modes, including single, dual and quad polarization, have been analyzed. In total, images from 18 different dates were included. Altogether, 56 forest stands with stem volume in the range of 45-650 m3 ha-1 (average 325 m3 ha-1) were analyzed by relating backscatter intensity to field data. The estimation accuracy of stem volume at stand level was calculated in terms of root mean square error (RMSE). For the best case investigated an RMSE of 30% was obtained for one of the single polarization images acquired in the winter season. In this case no saturation was observed for high stem volumes. The corresponding RMSEs for the dual and quad polarization images were between 62%, and 81%. The better results for single polarization might be explained by particularly favourable weather conditions at image acquisition. An extended evaluation will be performed to verify the cause.
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| 4. |
- Fransson, J.E.S., et al.
(author)
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Detection of clear-cuts using ALOS PALSAR satellite images
- 2008
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In: Proceedings of the European Conference on Synthetic Aperture Radar, EUSAR. - 2197-4403. ; 1-4
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Conference paper (peer-reviewed)abstract
- The objective of this study is to make a first evaluation of the possibilities to detect forest clear-cuts using high-resolution ALOS PALSAR FBD (Fine Beam Dual polarization) satellite images. New operational applications for mapping of changes in forest cover are of interest for government authorities in Sweden and in other countries with similar needs. The study was conducted in southern Sweden and included seven old coniferous stands located on flat terrain. Three of the stands were clear-felled and the remaining stands were left untreated for reference. Altogether, six PALSAR FBD images (look angle 34.3°, HH- and HV-polarization) acquired during the summer and fall seasons were analyzed. The difference in backscattering coefficient between the reference and the clear-felled stands was on average 2.4 dB and 2.9 dB for the HH- and HV-polarization, respectively. When comparing the backscattering coefficient before and after clear-felling the drop was found to be 1.7 dB and 2.3 dB for the HH- and HV-polarization, respectively.
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| 5. |
- Fransson, J.E.S., et al.
(author)
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Detection of forest changes using ALOS PALSAR satellite images
- 2007
-
In: IEEE Geoscience and Remote Sensing Symposium (IGARSS 2007), Barcelona, Spain, July 23-27, 2007. ; DOI: 10.1109/IGARSS.2007.4423308, s. 2330-2333
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Conference paper (other academic/artistic)abstract
- A controlled experiment has been performed to quantify the ability to detect clear-cuts using ALOS PALSAR data. The experiment consisted of 8 old spruce dominated stands with a size of about 1.5 ha, located at a test site in southern Sweden. Four of the stands were clear-felled and the remaining stands were left untreated for reference. A time series of PALSAR images were acquired prior to, during, and after treatment, including 7 Fine Beam Single polarization (FBS, look angle 34.3°, HH-polarization) SAR images. The results clearly show that the clear-felled stands could be separated from the reference stands. The drop in backscattering coefficient between the reference and the clear-felled stands was on average 2.1 dB. This implies that ALOS PALSAR data potentially can be used for large-scale mapping of changes in forest cover.
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| 6. |
- Fransson, J.E.S., et al.
(author)
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Mapping of Wind-Thrown Forests Using VHF/UHF SAR Images
- 2007
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In: IEEE 2007 International Geoscience and Remote Sensing Symposium (IGARSS 2007), Barcelona, Spain, July 23-27 2007. ; DOI: 10.1109/IGARSS.2007.4423313, s. 2350-2353
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Conference paper (other academic/artistic)abstract
- SAR images from the Swedish airborne CARABAS-II and LORA systems have been visually analyzed over simulated wind-thrown forest at both single tree and stand level. In ideal conditions, the results show that LORA is more accurate than CARABAS-II at detecting wind-thrown trees, regardless of tree size and direction of the fallen trees relative to flight heading. Furthermore, the visible single trees in the LORA images appeared more distinct than in the CARABAS-II images, which could be explained by the high resolution in the LORA images. Based on visual interpretation, it is likely that the detection of wind-thrown forests could be improved using VHF/UHF SAR images acquired both prior to and after a storm event.
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| 7. |
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| 8. |
- Kononov, Anatoliy, 1951, et al.
(author)
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Statistical Analysis of VHF-Band Tree Backscattering Using Forest Ground Truth Data and PO Scattering Model
- 2011
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In: IEEE Transactions on Geoscience and Remote Sensing. - 0196-2892 .- 1558-0644. ; 49:8, s. 3035-3046
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Journal article (peer-reviewed)abstract
- This paper analyzes the statistical properties of thevery high frequency (VHF)-band radar backscattering from coniferous trees by incorporating forest ground truth data into a physical-optics (PO) model that assumes horizontally transmit and receive polarizations and dominant double-bounce scattering from vertical stems standing on an undulating ground surface. The analysis shows that a statistically adequate model for the tree backscattering amplitude can be presented as a mixture of generalized gamma or lognormal distribution, and the mixture model can be reduced to a single density model if the trees withtrunk volumes exceeding an appropriate threshold are to be taken into account. The generalized gamma density is shown to provide an appreciably better fit to the exceedance functions associated with the PO model data than that for the lognormal density. The results can be used to design statistically adequate models of forest clutter for VHF synthetic aperture radar systems.
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| 9. |
- Magnusson, M., et al.
(author)
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Estimation of forest stem volume using ALOS PALSAR satellite images
- 2007
-
In: IEEE Geoscience and Remote Sensing Symposium (IGARSS 2007), Barcelona, Spain, July 23-27, 2007. ; DOI: 10.1109/IGARSS.2007.4423813, s. 4343-4346
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Conference paper (other academic/artistic)abstract
- A first evaluation of ALOS PALSAR data for forest stem volume estimation has been performed at a coniferous dominated test site in Sweden. In total, 7 Fine Beam Single polarization (FBS, look angle 34.3°, HH-polarization) and 7 Polarimetric (PLR, look angle 21.5°, HH-, HV-, VH-, and VV-polarization) SAR images were used. In total, 56 forest stands with stem volume in the range of 45-650 m3 ha-1 (average 325 m3 ha-1) were analyzed by relating backscatter intensity to field data. The estimation accuracy of stem volume at stand level was calculated in terms of root mean square error (RMSE). For the best case investigated an RMSE of 30% was obtained using one of the FBS images acquired in the winter season. The corre-sponding RMSEs for the PLR images with HH-, HV-, VH-, and VV-polarization were 65%, 65%, 62%, and 81%, respectively. The better results for FBS compared to PLR mode could be explained by particularly favorable weather conditions at image acquisition, or by the higher ground resolution in the FBS images, which makes small stands less sensitive to errors in geo-coding.
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| 10. |
- Sandberg, Gustaf, 1982, et al.
(author)
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A Physical-optics Model for Predicting VHF/UHF-band HH-pol Backscatter from Coniferous Forests in Undulating Terrain
- 2007
-
In: 5th International Symposium on Retrieval of Bio- and Geophysical Parameters from SAR Data, Bari, Italy, September 25-28, 2007, ESA, Istituto di Studi sui Sistemi Intelligenti per l`Automazione.
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Conference paper (other academic/artistic)abstract
- A physical optics based model for predicting backscatter from coniferous forest in the VHF- and UHF frequency bands is presented. It models the forest as a collection of stems standing on a well characterized undulating ground surface. The model is valid for SAR systems transmitting and receiving horizontal polarization (HH) and is useful for assessing the importance of ground topography in SAR images.SAR data from the airborne systems CARABAS-II (22-82 MHz) and LORA (230-470 MHz) and forest characterization on individual tree level were used to validate the model. It was found that the model was able to predict much of the backscatter variations due to surface topography. At best, coefficients of determination (R2) of 0.44 and 0.65 for the CARABAS and LORA case were found. In comparison it should be noted that R2 drops to about 0.1 if a flat ground is assumed. These results indicate that it is essential to consider ground topography when predicting HH-polarized SAR images in these frequency bands.The model failed to predict the absolute values of the backscatter intensity. Probable explanations are the lack of attenuation effects in the model and/or the value chosen for the dielectric constant of the stems.In the near future efforts will be placed into the task of extending the model to include more polarizations, especially HV. This includes e.g. adding the backscatter from branches and leaves/needles, accounting for attenuation effects and including random small scale variations in the surface description.
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| 11. |
- Sandberg, Gustaf, 1982, et al.
(author)
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Comparison of L- and P-band biomass retrievals based on backscatter from the BioSAR campaign
- 2009
-
In: Proceedings of IGARSS 2009 Symposium, Earth Observation – Origins to Applications, Cape Town, South Africa, 13-17 July, 2009. - 9781424433957 ; IV, s. 169-172
-
Conference paper (other academic/artistic)abstract
- With the continued threat of global warming, the need to obtain consistent and accurate measurements of the carbon stored in forests is strong. L- and P-band SAR backscatter data have shown to be sensitive to forest biomass, which in turn is coupled to the stored carbon. In this paper a biomass retrieval method is developed for L- and P-band using data from the BioSAR campaign conducted in Sweden during thespring 2007 over hemi-boreal forest. The results show that the use of L-band data gives an underestimation of biomass for stands with high biomass; while for P-band no such underestimation is seen. RMSEs are found to be 30-40% of the mean biomass for L-band and about 25% for P-band for stands with biomass ranging from 10 to 290 tons/ha.
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| 12. |
- Sandberg, Gustaf, 1982
(author)
-
Estimation of Forest Biomass and Faraday Rotation Using Polarimetric L-/P-band SAR
- 2009
-
Licentiate thesis (other academic/artistic)abstract
- At present the greatest source of uncertainty in the global carbon cycle is in the terrestrialecosystems. In order to reduce these uncertainties it is necessary to provide consistent andaccurate global estimates of the biomass contained in the forests of the world. One of themost promising methods for obtaining such estimates is through polarimetric SARbackscatter measurements at L-and P-band frequencies. This thesis aims to investigate thepossibility of retrieving forest biomass from L- or P-band SAR backscatter data. It alsoconcerns SAR image calibration. Well calibrated systems are necessary to ensure that errorsin estimates of physical properties, e.g. forest biomass, are not enlarged by noise or imagedistortions. Both system distortions, such as leakage between polarization channels, anddistortions caused by the ionosphere are studied.A calibration analysis was made on data from the L-band PALSAR system onboard theJapanese ALOS satellite. The data was shown to be of good quality, especially in terms ofradiometric stability and leakage between polarization channels. Following this an analysis ofFaraday rotation, i.e. image distortions caused by the ionosphere, was made for the PALSARimages. It was shown that Faraday rotation can be measured and corrected in PALSARimage, at least if the Faraday rotation is small.Forest biomass retrieval algorithms for P- and L-band SAR backscatter were developed andevaluated using data from the BioSAR-I campaign conducted in southern Sweden in 2007. Itwas found that HV- and HH-polarized backscatter was strongly related to biomass for both LandP-band. However, the L-band backscatter was found to have decreased sensitivity tobiomass for forest stands with biomass larger than about 200 tons/ha, resulting in anincreased error in the biomass estimates. For P-band this problem was not seen, and it wasfound that the biomass on stand level could be estimated using HV- and /or HH-polarized Pbandbackscatter with an error of 20-25% of the mean biomass for stands with biomassranging from 10 to 290 tons/ha.
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| 13. |
- Sandberg, Gustaf, 1982
(author)
-
Estimation of Forest Biomass and Faraday Rotation using Ultra High Frequency Synthetic Aperture Radar
- 2013
-
Doctoral thesis (other academic/artistic)abstract
- Synthetic Aperture Radar (SAR) data in the Ultra High Frequency (UHF; 300 MHz – 3 GHz)) band have been shown to be strongly dependent of forest biomass, which is a poorly estimated variable in the global carbon cycle. In this thesis UHF-band SAR data from the fairly flat hemiboreal test site Remningstorp in southern Sweden were analysed. The data were collected on several occasions with different moisture conditions during the spring of 2007. Regression models for biomass estimation on stand level (0.5-9 ha) were developed for each date on which SAR data were acquired. For L-band (centre frequency 1.3 GHz) the best estimation model was based on HV-polarized backscatter, giving a root mean squared error (rmse) between 31% and 46% of the mean biomass. For P-band (centre frequency 340 MHz), regression models including HH, HV or HH and HV backscatter gave an rmse between 18% and 27%. Little or no saturation effects were observed up to 290 t/ha for P-band. A model based on physical-optics has been developed and was used to predict HH-polarized SAR data with frequencies from 20 MHz to 500 MHz from a set of vertical trunks standing on an undulating ground surface. The model shows that ground topography is a critical issue in SAR imaging for these frequencies. A regression model for biomass estimation which includes a correction for ground slope was developed using multi-polarized P-band SAR data from Remningstorp as well as from the boreal test site Krycklan in northern Sweden. The latter test site has pronounced topographic variability. It was shown that the model was able to partly compensate for moisture variability, and that the model gave an rmse of 22-33% when trained using data from Krycklan and evaluated using data from Remningstorp. Regression modelling based on P-band backscatter was also used to estimate biomass change using data acquired in Remningstorp during the spring 2007 and during the fall 2010. The results show that biomass change can be measured with an rmse of about 15% or 20 tons/ha. This suggests that not only deforestation, but also forest growth and degradation (e.g. thinning) can be measured using P-band SAR data.The thesis also includes result on Faraday rotation, which is an ionospheric effect which can have a significant impact on spaceborne UHF-band SAR images. Faraday rotation angles are estimated in spaceborne L-band SAR data. Estimates based on distributed targets and calibration targets with high signal to clutter ratios are found to be in very good agreement. Moreover, a strong correlation with independent measurements of Total Electron Content is found, further validating the estimates.
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| 14. |
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| 15. |
- Sandberg, Gustaf, 1982, et al.
(author)
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Impact and modeling of topographic effects on P-band SAR backscatter from boreal forests
- 2011
-
In: Proceedings of IGARSS 2011 Symposium, Vancouver, Canada, 24-29 July, 2011. - 9781457710056 ; , s. 3522-3525
-
Conference paper (other academic/artistic)abstract
- P-band SAR backscatter has been proven to be useful for forest biomass prediction. However, there is a need for further studies on effects of topography on P-band backscatter. In this paper, two prediction models for backscatter are evaluated, one using only biomass as predictor and one which also includes topographic corrections. Data from the BioSAR 2007 and BioSAR 2008 campaigns are used to evaluate the models. A multi-scale error model which is able to handle data from several imaging directions is used. For HH, the slope correction on stand level used in this paper is unable to correct for topographic effects. This is consistent with previous results that within stand topographic variability has a significant impact on HH P-band backscatter. For HV and VV, the model which considers topography gives lower prediction errors than the model which does not include topography. Moreover, for these polarizations topographic the correction strongly reduce the variability in backscatter measurements between imaging directions for stands with ground slopes larger than about 5 degrees.
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| 16. |
- Sandberg, Gustaf, 1982, et al.
(author)
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L- and P-band backscatter intensity for biomass retrieval in hemiboreal forest
- 2011
-
In: Remote Sensing of Environment. - : Elsevier BV. - 0034-4257 .- 1879-0704. ; 115:11, s. 2874 - 2886
-
Journal article (peer-reviewed)abstract
- At present, the greatest source of uncertainty in the global carbon cycle is in the terrestrial ecosystems. In orderto reduce these uncertainties it is necessary to provide consistent and accurate global estimates of the worldforest biomass. One of the most promising methods for obtaining such estimates is through polarimetric SARbackscatter measurements at low frequencies. In this paper, the relation between polarimetric SAR backscatterat L- and P-bands and forest biomass is investigated using data acquired within the BioSAR-I campaign insouthern Sweden during 2007. Methods for estimating biomass on stand level using these data are developedand evaluated, and the results for the two frequency bands are compared. For L-band data, the best results wereobtained using HV-polarized backscatter only, giving estimation errors in terms of root mean square errors(RMSE) between 31% and 46% of the mean biomass for stands with biomass ranging from 10 to 290 t/ha, and an(adjusted) coefficient of determination (R2) between 0.4 and 0.6. For P-band data, the results are better thanfor L-band. Models using HV- or HH-polarized P-band backscatter give similar results, as does a modelincluding both HV and HH. The RMSEs were between 18 and 27%, and the R2 values were between 0.7 and 0.8.
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| 17. |
- Sandberg, Gustaf, 1982, et al.
(author)
-
Measurements of Faraday Rotation Using Polarimetric PALSAR Images
- 2009
-
In: IEEE Geoscience and Remote Sensing Letters. - 1558-0571 .- 1545-598X. ; 6:1, s. 142-146
-
Journal article (peer-reviewed)abstract
- For spaceborne synthetic aperture radar (SAR) systemsoperating at L-band frequencies or lower, the ionospheremay have a significant impact on the SAR images. The largesteffect at L-band is caused by Faraday rotation (FR). Severalstudies have modeled the effect of FR and/or devised models to measure and correct FR.With the launch of the fully polarimetric L-band system Phased Array-type L-band SAR (PALSAR), it has become possible to test both models and measurement techniques on real SAR data. In this letter, the quality of calibrated polarimetric PALSAR data is assessed, and FR is measured. It is found that residual crosstalk and channel imbalance are small in the PALSAR data. Two methods are used to measure FR, the first using in-scene distributed targets and the second using large trihedrals. The two methods show very good agreement. The measurements are compared with values of the total electron content using a linear model. It is found that the model and measurements are in good agreement, with a root-mean-square error of 0.3◦ or 15% of the mean FR angle.
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| 18. |
- Sandberg, Gustaf, 1982, et al.
(author)
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Measurements of Forest Biomass Change Using P-Band Synthetic Aperture Radar Backscatter
- 2014
-
In: IEEE Transactions on Geoscience and Remote Sensing. - : Institute of Electrical and Electronics Engineers (IEEE). - 0196-2892 .- 1558-0644. ; 52:10, s. 6047-6061
-
Journal article (peer-reviewed)abstract
- Methods to estimate forest biomass change have been investigated using experimental P-band synthetic aperture radar (SAR) data from the recent airborne campaigns BioSAR 2007 and BioSAR 2010 conducted over a hemiboreal test site in southern Sweden. Regression models based on backscatter change were developed using reference biomass change maps derived from high-density laser scanning data. Different regression models were developed for linear, square root, and logarithmic biomass change scales. The models were compared to the change maps based on laser data using twofold cross-validation, and estimation errors were evaluated using six 80 m by 80 m plots with detailed in situ measurements. The results indicate that the root-mean-square error of biomass change estimates based on P-band SAR backscatter data is about 15% or 20 t/ha. This suggests that not only clear-cuts but also growth and thinning can be measured. Simulations were performed in order to evaluate the possibility of using a space-borne P-band SAR for measurements of forest biomass change. The simulations show that, with 64 equivalent number of looks (ENL) and a 50% change in biomass, it is possible to correctly indicate whether the forest has gained or lost biomass. Similarly, for a biomass loss of more than 75%, a correct indication of the sign of biomass change can be achieved with only 8 ENL.
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| 19. |
- Sandberg, Gustaf, 1982, et al.
(author)
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Measurements of forest change using P-band SAR backscatter
- 2012
-
In: International Geoscience and Remote Sensing Symposium (IGARSS). - 2153-6996 .- 2153-7003. - 9781467311588 ; , s. 1652-1655
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Conference paper (peer-reviewed)abstract
- Using data from the recent BioSAR 2007 and BioSAR 2010 campaigns, it has for the first time been possible to measure forest biomass change using P-band SAR data. Regression models based on backscatter change have been developed using reference data derived from high density laser scanning data. The models were evaluated for six areas with detailed in-situ measurements, for which the maximum biomass loss and growth was 30% and 20%, respectively. For the best model the coefficients of determination was 55-89%. This result suggests that not only clear cuts but also forest growth and thinning can be measured using P-band SAR backscatter.
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| 20. |
- Sandberg, Gustaf, 1982, et al.
(author)
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PALSAR Calibration Results from Sweden
- 2008
-
Reports (other academic/artistic)abstract
- As part of a worldwide calibration and validation campaign for the Japanese Advanced LandObserving Satellite a calibration analysis of the Phased Array type Polarimetric SAR (PALSAR)was performed. Four 5 m large trihedral corner reflectors were deployed in southern Swedenand were imaged by PALSAR on numerous occasions. The results show that the pre launchspecifications are more than met, both for the radiometric and polarimetric performance. Inparticular, the absolute radiometric accuracy in this data set was found to be better than 0.5 dB,and the cross talk was estimated to be below -35 dB.
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| 21. |
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| 22. |
- Soja, Maciej, 1985, et al.
(author)
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Regression-Based Retrieval of Boreal Forest Biomass in Sloping Terrain using P-band SAR Backscatter Intensity Data
- 2013
-
In: IEEE Transactions on Geoscience and Remote Sensing. - 0196-2892 .- 1558-0644. ; 51:5, s. 2646-2665
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Journal article (peer-reviewed)abstract
- A new biomass retrieval model for boreal forest using polarimetric P-band synthetic aperture radar (SAR) backscatter is presented. The model is based on two main SAR quantities: the HV backscatter and the HH/VV backscatter ratio. It also includes a topographic correction based on the ground slope. The model is developed from analysis of stand-wise data from two airborne P-band SAR campaigns: BioSAR 2007 (test site: Remningstorp, southern Sweden, biomass range: 10-287 tons/ha, slope range: 0-4 degrees) and BioSAR 2008 (test site: Krycklan, northern Sweden, biomass range: 8-257 tons/ha, slope range: 0-19 degrees). The new model is compared to five other models in a set of tests to evaluate its performance in different conditions. All models are first tested on data sets from Remningstorp with different moisture conditions, acquired during three periods in the spring of 2007. Thereafter, the models are tested in topographic terrain using SAR data acquired for different flight headings in Krycklan. The models are also evaluated across sites, i.e., training on one site followed by validation on the other site. Using the new model with parameters estimated on Krycklan data, biomass in Remningstorp is retrieved with RMSE of 40-59 tons/ha, or 22-33% of the mean biomass, which is lower compared to the other models. In the inverse scenario, the examined site is not well represented in the training data set, and the results are therefore not conclusive.
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| 23. |
- Soja, Maciej, 1985, et al.
(author)
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Topographic Correction for Biomass Retrieval from P-band SAR Data in Boreal Forests
- 2010
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In: Proceedings of IGARSS 2010 Symposium, Remote Sensing: Global Vision for Local Action, Honolulu, Hawaii, USA, 25-30 July, 2010. - 9781424495641 ; , s. 4776-4779
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Conference paper (other academic/artistic)abstract
- The influence of the ground slope on radar backscatterhas been proven to be greater for lower radar frequencies dueto deeper canopy penetration. In this study, multiple heading, PbandSAR data of boreal forest in Sweden was used to find amodel for topographic correction for improved biomass retrieval.Eleven models were tested and the best model was selected. Theselected model was then used for biomass retrieval. Even bymeans of the most simplified approach, forest biomass could beestablished with a root-mean-square error of approximately 50t/ha for HV and 66 t/ha for HH.
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| 24. |
- Ulander, Lars, 1962, et al.
(author)
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Biomass Retrieval Algorithm Based on P-band BioSAR Experiments of Boreal Forest
- 2011
-
In: IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2011. Vancouver, 24-29 July 2011. - 9781457710056 ; , s. 4245-4248
-
Conference paper (other academic/artistic)abstract
- A new biomass retrieval algorithm based on P-band multi-polarization backscatter has been developed and evaluated based on SAR and ground data over boreal forest. SAR data collections were conducted on three dates at a test site in southern Sweden (Remningstorp, biomass
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| 25. |
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| 26. |
- Ulander, Lars, 1962, et al.
(author)
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BIOSAR 2010 - A SAR campaign in support to the BIOMASS mission
- 2011
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In: Proceedings of IGARSS 2011 Symposium, Vancouver, Canada, 24-29 July, 2011. - 9781457710056 ; , s. 1528-1531, s. 1528-1531
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Conference paper (other academic/artistic)abstract
- The ESA funded campaign BioSAR 2010 was carried out at the forestry test site Remningstorp in southern Sweden, in support to the BIOMASS satellite mission under study. Fully polarimetric SAR data were successfully acquired at L- and P-band using ONERA's multi-frequency system SETHI. In addition with other data types gathered, e.g. LiDAR and in-situ measurements, the compiled data set will be used for analyses and comparisons with biomass estimation results obtained at the same test site in the campaign BioSAR 2007, in which DLR's E-SAR made the SAR imaging. Detection of forest changes, robustness of biomass retrieval algorithms and long-term P-band coherence will be in focus as well as cross-validations between the two SAR sensors.
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| 27. |
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