• 09:20 Airborne Campaigns for Forest Information Extraction from InSAR and PolSAR Data

  Chen, Erxue; Li, Zengyuan; Tan, Xin; Feng, Qi; Zhao, Lei; Li, Lan Research Institute of Forest Resources Information Technique, Chinese Academy of Forestry

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  From 2012-2013, we have carried out one airborne campaign in the Daxinganling test site, which is located in the Northeast forest region of China. We will introduce the airborne campaign activities carried out in 2012, 2013, in China. Through this campaign, we acquired large volume of InSAR data by the two antennas X-band InSAR system and PolSAR data by the P-band SAR system, while the two SAR systems are on the same airplane to image the test sites at the same time. Airborne LiDAR and CCD images were also acquired, but only for the purpose of providing reference data to the accuracy validation of InSAR and PolSAR forest information extraction methods. During the flight period, we organized one ground survey team to collect ground true data, such as forest plot data for forest height and about ground biomass (AGB) calculation, LAI of both forest and crop vegetation, soil wetness and roughness, et al. Then, the key research progress of forest information extraction from the acquired high resolution X-band InSAR and P-band PolSAR data will be summarized. Firstly, we will introduce the key SAR/InSAR data processing steps, such as, X-band InSAR processing, SAR image geocoding terrain correction (GTC), forest height, forest AGB extraction from LiDAR and ground plots data. Secondly, we will introduce the forest information extraction methods and preliminary validation results from P-band PolSAR data and single baseline X-band InSAR data: (1) Forest height inversion using high resolution X-band InSAR data. We have validated the SINC InSAR coherence model for forest height inversion using the airborne single pass InSAR data over one relative flat area (Yigen), the results show that the SINC model works very well, the RMSE is 1.12m. (2) Forest AGB estimation using P-band PolSAR data. One empirical model taking local incidence angle into consideration was validated for the AGB estimation using the Airborne P-band PolSAR data over one area (Genhe) of relatively complex terrain and forest structure. The accuracy of the model was validated with thousand of LiDAR derived forest AGB, one RMSE of 15.98 ton/ha was achieved. The airborne campaigns covers very large area, but our methodology studies currently only use very few of them. In the future, the models will be further developed and applied to the forest information extraction of the whole test sites using all the airborne PolSAR data acquired.

  
   

• 10:00 A Comparison of UAVSAR and PolSARproSim+ Simulated Data for Multiple Vegetation Types

  Hensley, Scott; Ahmed, Razi; Lavalle, Marco; Neumann, Maxim; Michel, Thierry; Chapman, Bruce; Muellerschoen, Ron Jet Propulsion Laboratory, United States of America

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  UAVSAR, an airborne actively scanned L-band synthetic aperture radar has collected data over a wide variety of vegetation types including cropland, temperate and tropical forests and mangrove forests. Polarimetric interferometric observations of these sites cover a wide variety of physical and temporal baselines with varying terrain types and conditions. We have enhanced the ESA PolSARproSim polarimetric interferometric simulator to handle a variety of vegetation types and more accurately and efficiently model polarimetric interferometric observations of forested areas including the impacts of temporal correlation. In this talk we will compare actual UAVSAR observation of fully polarimetric and compact polarization data for various vegetation types to simulated data from PolSARproSIm+. This research was conducted at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

  
   

• 09:00 Mapping and validating forested landscapes in 3D using radar interferometry over the Laurentides super site

  Simard, Marc (1); Neumann, Maxim (1); Pinto, Naira (1); Sadeghi, Yaser (2); St-Onge, Benoît (2) 1: Jet Propulsion Laboratory, United States of America; 2: Université du Québec à Montréal, Québec, Canada

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  We present publically available validation datasets and results of polinSAR inversion of canopy height using UAVSAR data of the Laurentides Wildlife Reserve: a new cal/val super site for 3D mapping. The Laurentides Wildlife Reserve is a managed territory covering 7861km2 which is located between Québec city and Saguenay (Québec, Canada). The area is surrounded by the Jacques Cartier National Park, the Grands-Jardins National Parks and the Université Laval’s Montmorency experimental Forest. The variety of management practices offers the possibility for long term and comparative studies of documented natural forest dynamics as well as the impact of human, fires and insect disturbances. The large elevational gradient of the region (~1000m) allows to study variations in forest structure with types ranging from deciduous forests (temperate) near sea level, and the upper part of the Laurentides plateau is dominated by coniferous forests (boreal). We have collected field, high resolution lidar, and large footprint lidar data over large areas. All data is publically available. We have also collected repeat-pass UAVSAR data. We produced an extensive map of forest age based from Landsat time-series (1975-present) and historical aerial photos (1930’s) for the entire site. We used two airborne lidar data sets and field data to validate polinSAR inversions of canopy height. These are from the Laser Vegetation Imaging Sensor (LVIS) and from a high resolution dicrete Optech system (1m sampling). LVIS records the full waveform over a footprint of 20m. The relative height of the 100th percentile energy (RH100) was used to represent the top canopy height. We compared the field measurements with the tallest LVIS shot and UAVSAR polinSAR point within a 20 meters radius to account for field geolocation errors. We found least square linear fits with correlation coefficients of 0.94 and 0.93 for the closest and tallest neighborhood RH100 estimate respectively. At the time of writing this abstract, we have not yet performed validation of the high resolution lidar. However, from experience, it is expected to be as accurate as the field data itself. The UAVSAR system is a NASA facility instrument that routinely collects data, generally to study ground deformation. We used UAVSAR repeat-pass data acquired in 2009 to map forest canopy height at the landscape scale through polinSAR inversion and found correlations with LVIS estimates (RH100) of 0.88 and 0.94 when using the LVIS shot nearest to pixel center or the maximum within the neighborhood respectively. The root mean square (rms) errors are respectively 2.0 and 2.4. The accuracies for both RH100 and polinSAR are close to the field measurement error for a single tree which we estimate to be 10% of the height with a clinometer. In addition to validating polinSAR inversion of canopy height with field and lidar data, we investigate the inversion accuracy as a function of forest age, type and structure. While no significant dependence on canopy type was found, we were able to improve canopy height and accuracy estimates by adapting assumed temporal decorrelation to stand age. In the fast repeat-pass case (i.e. 45’), most systematic errors were observed to vary with terrain slopes. In the case of longer repeat-pass periods (2,5 and 9 days) various effects related to wind and particularly moisture (rain) were found to have major impacts on our ability to retrieve accurate estimates of canopy height but can be improved through knowledge of the temporal decorrelation levels. The latter has been measured in the 2009 dataset. The Laurentides super site is still under development and new datasets are added to the list. It is clear the public availability of field and lidar datasets will to be useful for the cross-validation of the current and future spaceborne and airborne systems. Such data will also help improve algorithms for retrieval of canopy height and biomass inversion. Our results have been obtained with repeat-pass data from the UAVSAR and are thus limited by temporal decorrelation effects. However, comparison with lidar and field data show that accurate results are obtained, while some improvements are necessary in complex terrains with topography.

  
   

• 10:20 ALOS2-INDONESIA REDD+ EXPERIMENT (AIREX): SOIL POOL CARBON APPLICATION

  Raimadoya, Mahmud Arifin Bogor Agricultural University, Indonesia

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  The bilateral REDD+ agreement between Indonesia and Norway has scheduled that performance based result phase will be started in 2014. Therefore, a transparent and reliable Monitoring, Reporting and Verification (MRV) system for the following carbon pools: (1) biomass, (2) dead organic matter (DOM), and (3) soil, is required to be ready prior to the performance based phase. While the biomass pool could be acquired by space-borne radar (SAR) application i.e. SAR Interferometry (In-SAR) and Polarimetric SAR Interferometry (Pol-InSAR), the method for soil pool is still needed to be developed. A study was implemented in a test site located in the pulp plantation concession of Teluk Meranti Estate, Riau Andalan Pulp and Paper (RAPP), Pelalawan District, Riau Province, Indonesia. The study was intended to evaluate the possibility to estimate soil pool carbon with radar technology. For this purpose, a combination of spaceborne SAR (ALOS/PALSAR) and Ground Penetrating Radar (200 MHz IDS 200 MHz IDS GPR) were used in this exercise. Two pairs of full polarimetric ALOS/PALSAR SLC imageries (2007, 2009, and 2010) were used to estimate tree height and underlying ground topography by POL-InSAR inversion procedure. In addition to that, spaceborne SAR was used also to map the extent of the peat soil. Mean while a total of 8(eight) GPR survey lines (DW-9, DW-10, DW-11, DW-12, DW-14, and DW-15) were implemented in the ground during the period of 25-30 August 2013 to measure the peat depth (thickness profile) in the tropical condition. The last two lines were measured twice at 117.5m length each, while the rest was 235m length at once These lines were distributed in different peat thickness condition, started from the shallow peat (40cm) at DW-9, to the deep peat (~6m) at DW-15. The initial result this study provides a promising outcome for improved soil pool carbon estimation in tropical peat forest condition. The volume estimation of peat soil could be measured from the combination of spaceborne SAR and GPR. Based on this volume, total carbon content can be generated. However, the application of this approach has several limitation such as: (1) GPR survey can only be implemented during the dry season, (2) Rugged Terrain Antenna (RTA) type of GPR should be used for smooth GPR survey in the surface of peat soil which covered by DOM, and (3) the map of peat soil extent by spaceborne SAR need to be improved. .

  
   

• 09:40 Assessment of TangoSat and Biomass tomographic modes for the characterization of boreal forests using airborne SAR measurements

  Ferro-Famil, Laurent (1); Tebaldini, Stefano (2) 1: University of Rennes 1, France; 2: Politecnico di Milano, Italy

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  This paper concerns the evaluation of the performance of the future TangoSAT and Biomass spaceborne missions for the characterization of boreal forests. This assessment is based on estimates and indicators obtained from airborne tomographic acquisitions led during the BioSAR 2 campaign. A comparison is led between results obtained from original high-quality measurements to those derived from degraded data sets, resulting from the transformation of the airborne signal according to the TangoSat and Biomass mission specifications. The performance is evaluated over several quantities, among which the most important ones concern the estimation of forest height, of the underlying ground topography and of the vertical structure of the forest volume. Apart from obvious changes between airborne and spaceborne configurations, particular features are accounted for in this study: - Unlike classical tomogarphic sensors, TangoSat will not acquire N SLC 2-D data sets, but instead (N-1) pairs of interferometric images with a low level of correlation between every two pairs. This aspect needs to be handled by a specific tomographic focusing scheme - The reduced range resolution in a spaceborne configuration deteriorates the spatial resolution of the retrieved results and affects tomographic performance through the range decorrelation effect - Compared to airborne measurements, spaceborne acquisitions are affected by lower SNR figures as well as by potential temporal decorrelation between the acquisitions The influence of each of theses factors on the estimation performance is first tested individually and is then assessed globally

  
   

Highlights

In May 2013, the Biomass mission concept was selected to become the next in the series of satellites developed to further our understanding of Earth.

Released: 21/06/2013

REPLAY EARTH EXPLORER 7 USER CONSULTATION MEETING (PART 1)

Released: 11/03/2013

POLinSAR 2013 Workshop

Released: 22/02/2013