Fábio Furlan Gama

Eucalyptus Biomass and Volume Estimation Using Interferometric and Polarimetric SAR Data

Abstract: This work aims to establish a relationship between volume and biomass with interferometric and radiometric SAR (Synthetic Aperture Radar) response from planted Eucalyptus saligna forest stands, using multi-variable regression techniques. X and P band SAR images from the airborne OrbiSAR-1 sensor, were acquired at the study area in the southeast region of Brazil. The interferometric height (Hint = difference between interferometric digital elevation model in X and P bands), contributed to the models developed due to fact that Eucalyptus forest is composed of individuals whose structure is predominantly cylindrical and vertically oriented, and whose tree heights have great correlation with volume and biomass. The volume model showed that the stand volume was highly correlated with the interferometric height logarithm (Log 10 Hint), since Eucalyptus tree volume has a linear relationship with the vegetation height. The biomass model showed that the combination of both Hint

Monitoring of Non-Linear Ground Movement in an Open Pit Iron Mine Based on an Integration of Advanced DInSAR Techniques Using TerraSAR-X Data

This work presents an investigation to determine ground deformation based on an integration of DInSAR Time-Series (DTS) and Persistent Scatterer Interferometry (PSI) techniques aiming at detecting high rates of linear and non-linear ground movement. The combined techniques were applied in an open pit iron mine located in Carajas Mineral Province (Brazilian Amazon region), using a set of 33 TerraSAR-X-1 images acquired from March 2012 to April 2013 when, due to a different deformation behavior during the dry and wet seasons in the Amazon region, a non-linear deformation was detected. The DTS analysis was performed on a stack of multi-look unwrapped interferograms using an extension of the SVD (Singular Value Decomposition), where a set of additional weighted constraints on the acceleration of the displacement was incorporated to control the smoothness of the time-series solutions, whose objective was to correct the atmospheric phase artifacts. The height errors and the deformation history provided by the DTS technique were used as previous information to perform the PSI analysis. This procedure improved the capability of the PSI technique to detect non-linear movement as well as to increase the numbers of point density of the final results. The results of the combined techniques are presented and compared with total station/prisms and ground-based radar (GBR) measurements.

Applying persistent scatterer interferometry for surface displacement mapping in the Azul open pit manganese mine (Amazon region) with TerraSAR-X StripMap data

Abstract. The Azul mining complex, located in the Carajás Mineral Province, Amazon region, encompasses the most important manganese mine in Brazil. Vale S.A. company operates three simultaneous open pit excavations (mines 1, 2, and 3) in the area, which are conducted on rock alteration products of low geomechanical quality related to sandstones, siltstones, and a lateritic cover. In order to monitor ground deformation, 33 TerraSAR-X (TSX-1) StripMap images covering the period of March 2012–April 2013 were used in the investigation. An advanced differential interferometric synthetic aperture radar (A-DInSAR) approach based on persistent scatterer interferometry (PSI) using an interferometric point target analysis algorithm was applied, and the results showed that most of the area was considered stable during the time span of the synthetic aperture radar acquisitions. However, persistent scatterers (PS) with high deformation rates were mapped over a waste pile, probably related to settlements, and also along the north flank of mine 1, indicative of cut slope movements toward the center of the pit. A spatial relationship of geological structures with PS was observed for this sector of the mine, given by PS showing deformation rates concentrated along a structural corridor with faults, fractures, and folds related to the Carajás fault system. Though only ground-based radar measurements for wall benches of mine 1 were available for a short time period of the TSX-1 coverage, the PS movement patterns showed concordance with geotechnical field measurements. The investigation emphasized the important role that satellite-based A-DInSAR can play for deformation monitoring and risk assessment in this kind of mining area.

Monitoring of surface deformation in open pit mine using DInSAR time-series: a case study in the N5W iron mine (Carajás, Brazil) using TerraSAR-X data

We present an investigation of surface deformation using Differential SAR Interferometry (DInSAR) time-series carried out in an active open pit iron mine, the N5W, located in the Carajás Mineral Province (Brazilian Amazon region), using 33 TerraSAR-X (TSX-1) scenes. This mine has presented a historical of instability and surface monitoring measurements over sectors of the mine (pit walls) have been done based on ground based radar. Two complementary approaches were used: the standard DInSAR configuration, as an early warning of the slope instability conditions, and the DInSAR timeseries analysis. In order to decrease the topographic phase error a high resolution DEM was generated based on a stereo GeoEye-1 pair. Despite the fact that a DinSAR contains atmospheric and topographic phase artifacts and noise, it was possible to detect deformation in some interferometric pairs, covering pit benches, road ramps and waste piles. The timeseries analysis was performed using the 31 interferometric pairs, which were selected based on the highest mean coherence of a stack of 107 interferograms, presenting less phase unwrapping errors. The time-series deformation was retrieved by the Least-Squares (LS) solution using an extension of the Singular Value Decomposition (SVD), with a set of additional weighted constrain on the acceleration deformation. The atmospheric phase artifacts were filtered in the space–time domain and the DEM height errors were estimated based on the normal baseline diversity. The DInSAR time-series investigation showed good results for monitoring surface displacement in the N5W mine located in a tropical rainforest environment, providing very useful information about the ground movement for alarm, planning and risk assessment.

Identification of the tropical forest in Brazilian Amazon based on the DEM difference from P and X bands interferometric data

In this paper the difference between digital elevation models, derived from P and X bands interferometric data, is used as a main information to identify land cover classes. The radar data used in this work were collected on September of 2000 over Tapajos National Forest, which is a region of Brazilian Amazon, Para State. The SAR images were acquired from an airborne polarimetric system, AeS-1, that could provide P and X bands interferometric data. During the radar mission ground survey was carried out, and the georeferenced information about the forest typology were acquired, and used as a support for the thematic identification and calibration of the remoted sensing data. The X-band DEM was generated using one-pass interferometric data and the P-band DEM was generated using two-pass interferometric data. The grid of the DEMs has a spatial resolution of 2.5 meters. Images from P and X bands and coherence maps were also used in order to improve the classification. Supervised and unsupervised classifications techniques are used and their results are shown.

Inventory of forest biomass in Brazilian Amazon: a local approach using airborne P-band SAR data

The objective of this study is to explore the use of airborne P-band SAR polarimetric data, to stratify biomass by primary and secondary vegetation typology. To ensure that different landscapes of Amazon upland forest are represented, a test-site located in the lower Rio Tapajos region, Pari State, was selected. The backscatter signals derived from the complex image of the P-band SAR were correlated with field data obtained from a forest inventory, for different physiognomic-structural aspects of the tropical rainforest The estimation of above-ground biomass for these forest types was modeled by DBH and total height measurements, including the use of general allometric equations. Statistical regression models were applied to establish the relationship between biomass and radar data at HH, HV and VV polarization. The overall objective of this P-band experiment is to improve the regional monitoring process of biomass dynamics as well as landscape changes, due to human action.

Continuous monitoring of biophysical Eucalyptus sp. parameters using interferometric synthetic aperture radar data in P and X bands

Abstract. This work aims to verify the applicability of models obtained using interferometric synthetic aperture radar (SAR) data for estimation of biophysical Eucalyptus saligna parameters [diameter of breast height (DBH), total height and volume], as a method of continuous forest inventory. In order to obtain different digital elevation models, and the interferometric height (Hint) to retrieve the tree heights, SAR surveying was carried out by an airborne interferometric SAR in two frequencies X and P bands. The study area, located in the Brazilian southeast region (S 22°53′22″/W 45°26′16″ and S 22°53′22″/W 45°26′16″), comprises 128.64 hectares of Eucalyptus saligna stands. The methodological procedures encompassed: forest inventory, topographic surveying, radar mapping, radar processing, and multivariable regression techniques to build Eucalyptus volume, DBH, and height models. The statistical regression pointed out Hint and interferometric coherence as the most important variables for the total height and DBH estimation; for the volume model, however, only the Hint variable was selected. The performance of the biophysical models from the second campaign, two years later (2006), were consistent and its results are very promising for updating annual inventories needed for managing Eucalyptus plantations.

Caracterização de uso e cobertura da terra na Amazônia utilizando imagens duais multitemporais do COSMO-SkyMed

The use of radar imagery is an alternative source of information to support the monitoring of the Amazon region, since the optical images have imaging limitations in tropical areas due to the occurrence of clouds. Therefore, the goal of this study is to analyze the radar images in X-band multi-temporal polarized obtained by COSMO-SkyMed satellite (COnstellation of small Satellites for Mediterranean basin Observation), in the intensity mode, isolated and/or combined with textural information, to thematic characterization of land use/land cover in the Humaita, Amazonas State region. The methodology used includes: analysis of the dual images obtained during two subsequent acquisitions, in order to explore the potential of the dataset as a quad-pol intensity; extraction of textural attributes from the co-occurrence matrix (Gray Level Co-occurrence Matrix) and subsequent contextual classification; statistical assessment of the thematic performance of the intensity and textural images, isolated and in polarized groups. Within the results achieved, the group formed only by the intensity images presented a better performance if compared to those containing the textural attributes. In this discrimination, the classes involved were forest, alluvial forest, reforestation, savannah, pasture and burned areas, yielding 66% overall accuracy and a Kappa value of 0.55. The results showed that X band images, from COSMO-SkyMed, StripMap mode (Ping-Pong), multi-polarized, presents a moderate potential to characterize and monitor the dynamics of land use/land land cover in the Brazilian Amazon.

SAR Interferometric Approaches for the Analysis of Structural Forest Parameters: State of the Art and Perspectives for Brazilian Studies

This paper presents three practical examples of airborne InSAR data application to improve the knowledge of forest structures. Two experiments were done in the Amazon tropical forest to study the spatial distribution of VLTs in the primary forest using LM filtering and a series of Markov processes and others, to map and model the estimation of biomass variations in primary and secondary forests. The third experiment refers to the relation of SAR data and the volumetric configuration of Eucalyptus sp. stands. The advances on the analysis of PolInSAR data are very helpful to increase, in the near future, the regional inventorying of land cover changes in the Brazilian territory.

Spectral reflectance of the Tucurui Reservoir waters in the Brazilian Amazon

The Tucurui reservoir was formed by damming the Tocantins river and flooding around 2430 Km2 of forest land. Its average depth is 18 meters with a dendritic shoreline which is responsible for a large variety of water masses with distinctive properties. This aquatic system therefore offers an unique opportunity for collection of wide variety of spectral data representative of the conditions usually found in Amazon reservoirs. These could be used as an spectral library for interpretation of imaging spectrometric data. This paper reports an experiment performed in April 1992 in which spectrometric data were collected over the Tucurui reservoir concurrently to water sampling at surface, at 50% light penetration depth, and at Secchi depth. Water samples were analyzed to obtain chlorophyll pigment, total suspended solids concentration and yellow substance attenuation. The preliminary results show two different types of optical waters, influenced mainly by total suspended solids concentration.