Radar interferometry offers new insights into threats to the Angkor site
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The conservation of World Heritage is critical to the cultural and social sustainability of regions and nations. Risk monitoring and preventive diagnosis of threats to heritage sites in any given ecosystem are a complex and challenging task. Taking advantage of the performance of Earth Observation technologies, we measured the impacts of hitherto imperceptible and poorly understood factors of groundwater and temperature variations on the monuments in the Angkor World Heritage site (400 km2). We developed a two-scale synthetic aperture radar interferometry (InSAR) approach. We describe spatial-temporal displacements (at millimeter-level accuracy), as measured by high-resolution TerraSAR/TanDEM-X satellite images, to provide a new solution to resolve the current controversy surrounding the potential structural collapse of monuments in Angkor. Multidisciplinary analysis in conjunction with a deterioration kinetics model offers new insights into the causes that trigger the potential decline of Angkor monuments. Our results show that pumping groundwater for residential and touristic establishments did not threaten the sustainability of monuments during 2011 to 2013; however, seasonal variations of the groundwater table and the thermodynamics of stone materials are factors that could trigger and/or aggravate the deterioration of monuments. These factors amplify known impacts of chemical weathering and biological alteration of temple materials. The InSAR solution reported in this study could have implications for monitoring and sustainable conservation of monuments in World Heritage sites elsewhere.The authors have utilized a set of Seasat synthetic aperture radar (SAR) data that were obtained in nearly repeat ground-track orbits to demonstrate the performance of spaceborne interferometric SAR (INSAR) systems. An assessment of the topography measurement capability is presented. A phase measurement error model is described and compared with the data obtained at various baseline separations and signal-to-noise ratios. Finally, the implications of these results on future spaceborne INSAR design are discussed.< >
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From the view of energy state of material, this paper introduces a concept of weathering potential in carrying out quantitative calculation of the relevant products at different stages of rock-weathering and primary soil-forming processes, elaborates respectively on weathering degree in the bio-weathering layer of rocks and during the formation of soil material and clay, and evaluats the further tendency of weathering in the above-mentioned stages. The authors have discovered that the scales of weathering potential of the materials increase successively in the three stages, which indicates that the products in the above-mentioned three stages must have undergone stronger and stronger weathering in the primitive forming process of soil in Fildes Peninsula, Antarctic. But, because of relatively weak chemical weathering, it is reasonable that there are much more skeleton grains and little clay in primary soils in this region. Meanwhile, the authors have also verified that the weathering potential of crude rock determines to some extent decrease in the products' weathering potential in the different stages in primary soil-forming, thereby plays an important role in the genesis and development of the primary soil in the studied area.
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Almost every year, flood and landslide occur at Pangkalan Lima Puluh Kota district, West Sumatra, Indonesia. These not only destroyed the agricultural but also isolated the area. The area is essential for supporting transportation connection in the center of Sumatra. However, the handling of this issues is insufficient then scientific information is a necessity. In this research, flood monitoring data extracted using InSAR processed by SNAP Sentinel-1 toolbox. The data were provided by European Space Agency (ESA) Ground Range Detected (GRD) High-resolution, Interferometric Wide Sentinel-1A observation product in ascending and descending orbit Both co-polarization VV and cross-polarization VH of satellites detected slightly different flood covered. The cross-polarization is high sensitive than co-polarization. The result was the present great potential of SAR satellite data for detection and delimitation flood risk in the area.
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Abstract In the preceeding paper (1), the general character of the weathering profile of granodiorite indicated that physical weathering was prevailing in the lower two zones and chemical weathering was dominant in the upper zone of the profile. It was also shown that the weathering profile has been developed in a severe chemical environment under oxidizing condition such as that encountered in the subtropical or warm temperate humid climate. The chemical weathering of the constituent minerals of the parent rock and the materials produced from them in such a weathering environment will now be examined. In this paper, the stability or duration of the primary minerals will bestudied.
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The Interferometric Synthetic Aperture Radar (InSAR) phase shifts can be considered as overlapping contributions from different phenomena. Based on this, the new ` InSAR-ICA' technique has recently been developed for deriving the nominal topographical and surface deformation components. The InSAR-ICA's innovation is its capability to reach good performance by minimal or null non-SAR data, even in case of very few SAR interferograms available for the observational area. Therefore, it allows the SAR monitoring of unreachable areas and in case of no availability of meteorological data that are sufficiently simultaneous to SAR acquisition times for the atmospheric corrections. In this paper, a summary description of the InSAR-ICA technique is given, with specific references to the usefulness of its application on mountainous areas.
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Soil production function
Weathering steel
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Forests are an integral component of local ecosystems as well as the global carbon cycle and as a result of the subject of intense human interest and study. Synthetic Aperture Radar (SAR) and Interferometric Synthetic Aperture Radar (InSAR) are proven technologies and have both been used to image forests across weather and daylight conditions. Both SAR and InSAR systems require the formation of at least one synthetic aperture which is not an instantaneous occurrence. Rather, synthetic apertures are formed by coherently combining multiple adjacent radar observations which are collected temporally close but not simultaneously. The time required to collect sufficient measurements to form a synthetic aperture or the time between synthetic aperture collections in the case of an InSAR system are of interest in this study as both delays enable an observation of temporal processes, such as a moving wind field, and their impact on SAR and InSAR measurements. We present an approach to quantify the effect of wind on a SAR system's ability to achieve coherence between adjacent measurements and that of an InSAR system to accurately estimate the canopy height of a tree. We propose to simulate a set of physically realistic trees and to expose each to the same set of incident wind fields. During the exposure, the instantaneous geometry of each tree will be stored and then imaged by a combined SAR and InSAR simulator thereby generating a temporal record of wind-blown tree geometries and their corresponding SAR and InSAR measurements. This collection of tree geometries, wind fields, and electromagnetic simulations will be used to develop a relationship between an incident wind field and the expected impact on SAR and InSAR measurements.
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From the view of energy state of material,this paper introduces a concept a concept of weathering potential in carrying out quantitative calculation of the relevant products at different stages of rock-weathering and primary soil-forming processes,elaborates respectively on weathering degree in the bio-weathering layer of rocks and during the formation of soil material and clay,and evaluats the further tendency of weathering in the above-mentioned stages.The authors have discovered that the scales of weathering potential of the materials increase successively in the three stages,which indicates that the products in the above-mentioned three stages must have undergone stronger and stronger weathering in the primitive forming process of soil in Fildes Peninsula,Antarctic.But,Because of relatively weak chemical weathering,it is reasonable that there are much more skeleton grains and little clay in priamry soils in this region.Meanwhile the authors have also verified that the weathering potential of crde rock determines to some extent decrease in the products' weathering potential in the different stages in primary soil-forming,thereby plays an important role in the genesis and development of the primary soil in the studied area.
Soil production function
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Kola peninsula
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Based on the investigation research of weathering characteristics and affecting factors of weathering action on surrounding rock of the Longmen cavern, Luoyang, it is pointed that the main forms of weathering action are biological weathering and physical weathering. And the weathering meachanism is also studied. With the growing of plants on the top of the mountain, the primary effecting factor of weathering damage has beening changed into biological weathering from previous physical weathering. The biological weathering damage include mainly the mechanical damage of plant rootsystem and the biological-chemical damage of plant humic compounds. So the damage of biological weathering action should be paid more attention.
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Weathering is an important factor leading to the deterioration of mechanical properties of rocks,and the sensitive indices of weathering are the basis for quantificationally evaluating weathering degrees of rocks and determinging the depth of rock weathering.In this paper,based on a large number of chemical test data of rock samples under different weathering grades,time and different depths,the sensitive chemical weathering indices are studied.The study indicates that among the chemical weathering indices previously proposed,WI,WPI and LOI,show apparent monotonicity and sensitivity corresponding to the variations of weathering degree,time and depth.Therefore,the three indices can be used to evaluate the weathering degree of rock,and to determine the depth of weathering.Otherwise,ALK,a and b show no monotonicity corresponding to the variation of weathering degree,so they can not be used to evaluate the weathering degree of rock and determine the depth of weathering,either.
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