ALOS PALSAR Satellite Research Articles

Utilizing Multi-Temporal ALOS/PALSAR Backscatter Data to Detect Deforestation in the Indonesian Tropical Forest

Deforestation detection mapping has been analyzed using Synthetic Aperture Radar (SAR) data from the ALOS PALSAR satellite. SAR is a promising tool for deforestation mapping in tropical forest regions because microwave energy can penetrate clouds. This study examined the effect of SAR polarization on the accuracy of deforestation mapping and the seasonal variation of radar backscattering values in Riau Province, Indonesia. Image differencing was used to determine the threshold value for distinguishing between forest and non-forest areas. The difference between HV (horizontal transmit-vertical receive) and HH (horizontal transmit-horizontal receive) polarization was used as the discriminant variable. The correlation between radar backscattering value and accumulated rainfall was also analyzed to assess the effect of seasonal change. The findings demonstrated that the accuracy of deforestation detection mapping using HV polarization outperforms that achieved with HH polarization. Moreover, seasonal variations in rainfall were observed to influence radar backscatter signatures in bare soil, acacia, and oil palm, though no such influence was detected in forested areas. The accuracy of deforestation detection mapping, employing the thresholding method, reached a rate of 92.21%. During the period from November 2007 to July 2009, forested areas in Riau experienced a reduction, decreasing to 6.77%, and further decreasing to 6.08% by October 2010.

Pengaruh Koreksi Ionosfer Terhadap Pergeseran Vertikal Pada Citra Satelit ALOS-PALSAR

Interferometric Synthetic Aperture Radar (InSAR) is an effective technique for changing the earth's surface with wide coverage and high accuracy. However, the accuracy of InSAR can be affected by wave propagation activity in the atmosphere. The ionospheric medium in the atmosphere contains free electrons which cause unstable waves to produce bias. Therefore, it is necessary to correct the ionosphere in SAR image processing so that it does not contain bias. This study examines the effect of ionospheric correction on vertical deformation in ALOS-PALSAR satellite imagery. The data used includes satellite image data and GNSS. Image data is processed by considering the presence or absence of ionospheric correction so that the results can be analyzed to determine the effect of the ionosphere on SAR images. GNSS data is processed by a static method to produce coordinates that can be used as a reference for validating the results of SAR image processing. The results of SAR and GNSS image processing are then visualized in the form of a vertical deformation map to facilitate the analysis of the results. The results showed that the direction of the vertical deformation in the ionospheric corrected satellite image was consistent with the direction of the vertical deformation in the GNSS. This indicates that the ionospheric correction affects the vertical deformation in the satellite image. In the process of vertical changes, there are obstacles, namely the vertical point reference has not been used as a validation of the results. In addition, there are no other satellite image references to compare the results of the ALOS-PALSAR satellite image processing.

Lineament Mapping of Jabal Arkenu in Southern Libya

Remote sensing technology is an important technique in studying perilously and hard-to-reach places for investigating them in the field. Furthermore, it provides fast and accurate data to characterize natural features or physical objects on the ground. Remote sensing data could be used with other approaches to provide a more comprehensive overview of the feature of interest.
 Accordingly, in this study, the linear features of Jabal Arkenu, in the Kufrah Basin, south of Libya, were studied remotely. The main source data is a satellite image produced from the Alos Palsar satellite, which has a spatial resolution of 12.5 meters. The lineament features map of Jabal Arkenu was created by analyzing several shadow relief images. The length, density, direction and intersection of the lineaments have been extracted from the lineaments map and compared to provide clear maps for determining the type of faults, structural relationships and the geology in the study area. Additionally, the central part of Jabal Arkenu is dominated by high to very high lineament density, while the greater part of the study area is characterized by medium to low lineament density. The dominant direction of the analyzed lineaments is in the northeast direction, and they are concentrated in the north and south parts. Some linear features exist as a boundary between Nepheline syenite with Cambrian Sandstone and Phonolite with Syenite granite.

Spatio-temporal prediction of water production in basins without records

This study carried out the spatio-temporal prediction of water production in two micro-basins without records, located in Venezuela. Geomorphological characteristics of micro-basins were obtained using digital elevation models acquired from ALOS PALSAR satellite. Two models were included for spatio-temporal prediction of hydrometeorological variables. The first model involved deterministic and stochastic components, calibrated using two-time series (TS). TS-1 consisted of records from 227 precipitation stations and 62 evaporation stations managed by the Environment Ministry during 1980-1999. TS-2 included records from 28 precipitation stations and 18 evapotranspiration stations collected by the National Institute of Meteorology and Hydrology during 2015-2018. The second model estimated effective precipitation from TS-2 precipitation maps, runoff coefficient from land use and land cover (LULC) prediction. The LULC was estimated on 59 Landsat 8OLI images for 2015-2018. The validation was carried out with observations of the Hydrological Central Company, resulting in determination coefficients upper to 0.95.

Determination of the relationship among compound Topographic Index (CTI), soil properties and land-use in karst ecosystems

ABSTRACT Topography is a key factor that affects edaphic, climatic, and biotic factors directly or indirectly. Relationships between Compound Topographic Index (CTI) model and soil properties were investigated in order to determine the ecological potential of the area in order to plan the sustainability of the fertile lands and the rehabilitation of the degraded areas in the study area. Totally 84 soil samples (0–20 cm) collected from different land use types (forest, cropland, rangeland) in Karst Mountain, Andırın-Kahramanmaras, Turkey. The CTI distributions are generated from digital elevation data of 12 m resolution obtained from AlosPalsar Satellite images. Although CTI values changed to Forest> Cropland> Rangeland, the highest correlation was found between CTI and soil moisture content in rangeland (R2 = 0.81). Lower correlations were found with other land uses (R2 = 0.63 in Cropland and R2 = 0.31 in Forest). CEC and Clay content were found to have a significant (p < 0.01) positive correlation with Curvature. Despite a distinctive topographic structure of karst ecosystems, these correlations verified the influence of topography on soil properties. CTI, which has strong correlations with soil moisture content can be used in planning reclamation processes of degraded karst ecosystems.

Lineament Assessment of Aynak Copper mine using Remote Sensing approach

This research developed a new approach to extract the lineaments using Landsat, QuickBird and ALOS PALSAR satellite remotely sensed data in Aynak copper mine which is located in Kabul tectonic block and the Tethyan Copper Belt of Afghanistan. Lineaments and trench directions are not relatively studied in the study area which will bring obstacles in exploration and extraction of the mine. This research aims to extract the lineaments for studying the better trench direction in the study area. Lineaments such as faults and joints are extremely important structures that not only show the surface structure but also give us important knowledge about the subsurface of the earth. Afghanistan is a part of the Alpine-Himalayan orogenic belt which suffers from high tectonic movements in some areas, especially north-eastern and central parts which leads to the occurrence of different lineaments and unconformities. Lineaments can be surveyed and mapped using field geological survey or using satellite remotely sensed data. Satellite remote sensing data costs less and takes less time compare to field geological survey for lineament extraction. This research used Landsat 8 natural color with 2, 3, 4 band composition, QuickBird 1m resolution, and ALOS PALSAR 12.5 m satellite imagery to detect and map the lineaments in the Aynak copper mine area in Afghanistan. Geomatica software was used for lineament extraction using the Manual technique. Then the rose diagrams of the lineaments were plotted using Polar Plots extension of ArcGIS. Next, the rose diagrams derived from the two mentioned lineament extraction techniques were compared and evaluated. Global Mapper software was used for the extraction of lineaments using Visual technique and to map the rivers and ridges in the Aynak area of interest for validation of the results. Finally, the best orientation for trenches in Aynak copper mine was derived. This study found that faults and joints in the study area have a NE-SW trend and directions. This study will contribute to a better understanding of the trench direction and mineral exploration in Aynak copper mine.

Geomorphology of the northeastern extreme of Isla Grande de Tierra del Fuego, Argentina

ABSTRACT A 1:60,000 scale geomorphological map of the Argentine side of the northeastern extreme of Isla Grande de Tierra del Fuego in southernmost South America is presented. This paper describes and summarizes the geomorphology of the mapped area, which includes glacial, periglacial, fluvial, coastal, aeolian, lacustrine, and anthropogenic landforms that span over 680 km2 north of San Sebastián Bay in a sparsely populated semiarid and cold steppe used for sheep breeding and hydrocarbon extraction. We used Landsat-8, Sentinel-2, and ALOS-PALSAR satellite products combined with field validation to create the map. Glacial advances and retreats as well as climatic and sea level fluctuations that controlled fluvial systems and coastal dynamics were the main sculptors of the landscape during the Late Cenozoic. Aeolian, lacustrine, and anthropogenic activity were later minor contributors. The presented free, open access, vector geomorphological map is intended to be a supporting tool for multidisciplinary researchers and decision-makers.

Influência da expansão urbana aliada às características morfométricas nas ocorrências de inundações: estudo de caso no município de João Monlevade-MG

O presente estudo teve como objetivo analisar a influência da expansão urbana aliada às características morfométricas nas ocorrências de inundações, no município de João Monlevade-MG. Para a mensuração e classificação das características morfométricas e a obtenção do mapa de uso e ocupação dentro da bacia foram utilizadas uma base de dados disponível no site da Agência Nacional de Águas (ANA) e imagens do satélite Alos Palsar. O uso e ocupação do solo foi dividido em 6 classes. A área de vegetação foi a queapresentoumaior porcentagem na bacia. Para a caracterização morfométrica da bacia, utilizando o software ArcGis 10.3, foi necessário a quantificação da área, perímetros, comprimento do canal principal da bacia e seu comprimento vetorial . De posse destes dados, calculou-se o coeficiente de compacidade (Kc), fator de forma (Kf), índice de circularidade (Ic), índices de declividade, índice de sinuosidade (Is), amplitude altimétrica (Hm), densidade de drenagem (Dd), hierarquia dos canais, número total de canais d’água na bacia e relação relevo (Rr). Diante dos resultados obtidos foi possível constatar que a bacia hidrográfica do córrego Carneirinhos possui uma suscetibilidade natural média ao desenvolvimento de inundações. Contudo, por meio da análise do uso e ocupação do solo foi constatado que os usos antrópicos prevaleceram e um aumento da expansão urbana foi observado, fato que tende a intensificar os processos de inundação na área.

Comportamento hídrico das depressões cársticas da região de Lagoa Santa, MG

As depressões cársticas se configuram como importantes feições dissolutivas presentes principalmente em regiões calcárias. À luz da típica geomorfologia e hidrogeologia cárstica, este trabalho apresenta as investigações realizadas nas depressões cársticas situadas sobre as rochas pelito carbonáticas do Grupo Bambuí, localizadas nos arredores da Área de Proteção Ambiental (APA) Carste Lagoa Santa (MG). As investigações tiveram como principal objetivo a compreensão do comportamento e desempenho hídrico das 393 depressões cársticas detectadas a partir de Modelo Digital de Elevação (MDE) derivado de uma imagem do satélite ALOS PALSAR. As etapas se constituíram fundamentalmente de geoprocessamento em ambiente SIG, foto observação através de imagens do Google Earth Pro, classificação supervisionada em imagens multiespectrais dos satélites Landsat registradas em quatro períodos hidrológicos distintos (ano com índice pluviométrico normal e ano atipicamente seco). O coeficiente de Kappa e acurácia geral indicaram que as classificações supervisionadas realizadas obtiveram resultados excelentes. As análises estatísticas multivariadas revelaram que a presença de lagoas no interior das depressões cársticas após o período de estiagem em ano hidrológico normal ou em ano de excepcional stress hídrico está relacionada com a morfologia e morfoestrutural. Isto é, as depressões maiores, com grandes profundidades, altos índices de eixos de alongamento e grandes áreas de maciços calcários em seus interiores são aquelas mais favoráveis a possuírem água em seus interiores.

Coastal lateral spreading in the world heritage site of the Tramuntana Range (Majorca, Spain). The use of PSInSAR monitoring to identify vulnerability

The Balitx area is located on the steep coastal side of the Tramuntana Range (Majorca), a mountainous region which was declared a World Heritage Site by UNESCO in 2011 in the cultural landscape category. The Balitx site was occupied by farming areas with dry stone constructions and water storing systems of both Roman and Islamic origin. The coastal landscape is characterised by a large fault escarpment of up to 260 m in height. Lateral spreading processes are favoured by local stratigraphy and tectonics in an energetic coastal dynamics scenario. Block spreading morphologies are identified along the escarpment, with large, rocky blocks of volumes up to 60 × 103 m3 moving very slowly until their collapse. Consequently, a thick and highly karstified breccia deposit is accumulated at the base of the scarp. The lowest, oldest breccia outcrop has been dated (Th/U), and an age of 82.5 ± 5.6 kyr was obtained, reflecting the time span this process has been active. Additionally, numerous geomorphological slope features are identified in the area: landslides, rockfalls, and, more specifically, long and deep cracks in the hanging wall block of the fault, which also reveal active lateral spreading processes. Coastal dynamics have been investigated by interpreting offshore geophysical studies, bathymetry data and borehole information to determine the role of wave energy in the stability of the slope. Additionally, 14 SAR images from the ALOS PALSAR satellite have been exploited for the present work, covering a period spanning from 2007 to 2010, an anomalous rainy period in the region. Images were processed using the Persistent Scattered Interferometry (PSI) technique. PSInSAR results reveal that the rate of movement for the Balitx lateral spreading is extremely low (− 5.2 mm/year on average), but major activity has been detected in the NE sector, where velocity rates can reach values of up to − 16 mm/year Coastal dynamics in the area can explain this, as a small island generates wave refraction and reflection determining more intense erosive processes in the NE part, which lead to a greater destabilising effect on the slopes. A simple vulnerability approach has been developed to take the elements of cultural heritage into account. Vulnerability increases from SW to NE, in accordance with landslide activity. The Balitx case study could provide a testimony to the effects of mass movements and coastal dynamics in an exceptional example of Mediterranean agricultural landscape.

Multi-sensor forest vegetation height mapping methods for Tanzania

ABSTRACTThis paper proposes a new method for mapping of forest cover in Tanzania, in the form of yearly estimates of average vegetation height from time-series of Landsat and ALOS PALSAR satellite images. By using airborne laser scanning data and Landsat-8 data from 2014, a regression between average vegetation height and the specific leaf area vegetation index is established. By using all available Landsat acquisitions of the same area within 1 year, and producing a yearly estimate of vegetation height, the estimation error variance is reduced. The variance is further reduced by Kalman filtering the sequence of yearly estimates. A multi-sensor version of the method comprises application of the radar backscatter when L-band SAR data is available. To conclude, we have demonstrated that estimation of mean vegetation height is possible from dense time series of optical and SAR satellite data. Change detection was able to detect areas with total loss of biomass.

The influence of filtration and decomposition window size on the threshold value and accuracy of land-cover classification of polarimetric SAR images

ABSTRACTIn this study we use ALOS PALSAR satellite data to classify land cover using a decision tree algorithm. We apply polarimetric decomposition methods to coherence and covariance matrices obtained from the data and then use threshold values to classify terrain. We evaluate the influence of speckle filter and decomposition window sizes on the threshold value used in the decision algorithm and on the accuracy of the classification. We also study the sensitivity of the classification to the accuracy of the threshold value.First, we processed a fully polarimetric Synthetic Aperture Radar (SAR) L-band image using different sizes of speckle filtration and decomposition window (3 × 3 pixels, 5 × 5, 7 × 7, 9 × 9), and the decomposition methods available in PolSARPro software. We evaluated these methods and chose the most efficient. Then we developed a simple hierarchical classification scheme based on threshold values. In the first step we divided the terrain into smooth and rough areas and then separated these into more detailed subclasses (water and agriculture, and forest and urban) which correspond to smooth and rough areas, respectively. A more detailed analysis separated continuous and discontinuous urban fabric and deciduous and coniferous forests. The maximum overall accuracy of the classification was 86.1% for the four main land cover classes, and 80.4% for the six more detailed classes. The accuracy of the classification dropped by about 10% when non-optimal window sizes were used in image filtration or decomposition.

OCEAN WAVE ENERGY ESTIMATION USING ACTIVE SATELLITE IMAGERY AS A SOLUTION OF ENERGY SCARCE IN INDONESIA CASE STUDY: POTERAN ISLAND’S WATER, MADURA

Abstract. Ocean wave energy is one of the ORE (Ocean Renewable Energies) sources, which potential, in which this energy has several advantages over fossil energy and being one of the most researched energy in developed countries nowadays. One of the efforts for mapping ORE potential is by computing energy potential generated from ocean wave, symbolized by Watt per area unit using various methods of observation. SAR (Synthetic Aperture Radar) is one of the hyped and most developed Remote Sensing method used to monitor and map the ocean wave energy potential effectively and fast. SAR imagery processing can be accomplished not only in remote sensing data applications, but using Matrices processing application as well such as MATLAB that utilizing Fast Fourier Transform and Band-Pass Filtering methods undergoing Pre-Processing stage. In this research, the processing and energy estimation from ALOSPALSAR satellite imagery acquired on the 5/12/2009 was accomplished using 2 methods (i.e Magnitude and Wavelength). This resulted in 9 potential locations of ocean wave energy between 0-228 W/m2, and 7 potential locations with ranged value between 182-1317 W/m2. After getting through buffering process with value of 2 km (to facilitate the construction of power plant installation), 9 sites of location were estimated to be the most potential location of ocean wave energy generation in the ocean with average depth of 8.058 m and annual wind speed of 6.553 knot.

Using the Wishart maximum likelihood classifier for assessing the potential of TerraSAR-X and ALOS PALSAR data for land cover mapping

Land cover is a fundamental variable that impacts and links with many parts of the human and physical environments. However, mapping land cover particularly in the tropical regions is problematic due to persistent cloud cover, large and inaccessible areas, political instability, poor access to mapping data and weak government support to mapping agencies and research institutions. The objective of this study was to assess the potential of the dual-polarised TerraSAR-X (TSX) and quad-polarised L-band ALOS PALSAR satellite data for land cover mapping in the complex terrain of the Bwindi Impenetrable National Park (BINP). Polarimetric analysis of the satellite images was carried out using the Wishart maximum likelihood classification (WMLC) algorithm. A total of nine land cover classes were selected for analysis. For each land cover class, representative samples were extracted and used for land cover classification and accuracy assessment based on the interpretation of the high-resolution IKONOS satellite images as well as the a priori knowledge of the study area. Overall land cover classification accuracies of 86% and 43.9% were obtained using ALOS PALSAR and TSX data, respectively. These results indicate a realistic potential of using ALOS PALSAR data for land cover mapping compared with TSX data.

Mapping Geo-Hazard by Satellite Radar Interferometry

This paper describes the application examples of satellite interferometric synthetic aperture radar (InSAR) in exploring potential geo-hazards and mapping geo-related disasters, including earthquakes, landslides, and land subsidence, triggered by natural forces and/or human activities. Satellite images were acquired from the Japan Aerospace Exploration Agency's (JAXA's) ALOS-PALSAR satellite, the Euroeapn Space Agency's (ESA's) Envisat-ASAR satellite, and the German Aerospace Center's (DLR's) TerraSAR-X satellite, covering frequency bands of L, C, and X, respectively. The study areas include Taiwan and Vietnam because both regions are prone to greater risks of geo-hazards and natural disasters. A series of C-band and L-band both ascending and descending mode SAR imagery data were used to map the deformation and subsidence of the environmentally sensitive areas. With the historical information and fast updated data sets, long-term and short-term subsidence patterns can be effectively and efficiently obtained. Excellent agreements were obtained as compared with Global Positioning System (GPS) and leveling measurements. Stacking of dual-beam mode as ascending and descending mode could extract the vertical displacement more easily and reduce the influence from the horizontal displacement. In summary, the advance of satellite radar interferometry provides a vital mapping to detect and identify geo-hazard and potential geo-disaster in general.