Remote Sensing Tools Research Articles

Remote Sensing and GIS Tools for the Groundwater Withdrawals Quantification

Among the main difficulties and uncertainties in determining the water balance of an area there is the calculation of groundwater withdrawals. This factor is particularly important in the case of aquifers, whose extension and intensive agricultural use make direct quantification methods unfeasible (i.e. flow meter measurements and electricity consumption). This paper presents a method for quantifying groundwater withdrawals used for agriculture supported by remote sensing and Geographic Information System (GIS). Through the process of obtaining a classification of irrigated crops with a high degree of accuracy by analyzing multi-temporal and multi-spectral satellite imagery, these data are integrated into a GIS, intersected with a correct estimation of needs values crop irrigation and corrected to adapt agricultural practices in the area. The result provides information about the spatial and temporal distribution of the volume of groundwater pumped and used in agriculture with greater accuracy than traditional methods and with much lower cost than any system of direct measurement (about 1 $/ha from the irrigation of the 50,000ha). This methodology has been applied and validated in Mancha Oriental Aquifer System (Spain, 7,260 km), in which withdrawals used for agriculture (approx. 400 Mm) is over 90% of water consumed. Keywords-Water Resources; Agriculture; Groundwater; Pumping; Remote Sensing

Assessment of Landscape Characteristics and Changes in the Khangchendzonga National Park, Sikkim Himalaya, India

The Khangchendzonga National Park (KNP) in India forms a part of the eastern Himalaya global biodiversity hotspot. Being the third highest protected area in the world, much of the park is inaccessible and has remained least understood. In this study, Remote Sensing and GIS tools were used to quantify landscape composition, configuration and patterns of changes in vegetation cover. From Landsat ETM+ data, 10 land cover types could be classified with 81% accuracy, which showed relatively higher coverage of snow, rock and alpine meadows. FRAGSTATS recognized 70790 patches with mean patch size of 1.2 ha. Watershed based approach showed that parts of KNP that had higher landscape heterogeneity, reflected a greater Himalayan character, high elevation gradient, east west orientation and not dominantly sculptured by valley glaciers. Riverine areas were found to be susceptible to glacial lake outburst and flash floods. Also vegetation cover has substantially declined at lower elevations (1000 to 2500 m) in the last three decades, particularly in portions not shielded from the villages by buffer forests. The park management needs to evolve innovative co-management models, use the riverine zone carefully, strengthen buffer zone management and prioritize conservation measures in the high impact areas.

Assessing the activity of a large landslide in southern Italy by ground-monitoring and SAR interferometric techniques

Landslides are recognized as one of the most damaging natural hazards in Italy. Campania region represents a complex geological setting, where mass movements of different types are widespread, and urban expansion can be increasingly seen by the presence of buildings and infrastructure in landslide-prone areas. In such a context, monitoring of unstable slopes represents a key activity in the process of landslide risk prevention and mitigation, in order to correctly establish a cause–effect correlation and to predict the possible reactivation phases that may result in high costs for the human society. This article focuses on the application of different methods of landslide analysis and monitoring, including those developed more recently and based on data acquired by satellites and processed by synthetic aperture radar (SAR) interferometric techniques. The study area is a small town, Calitri, known worldwide for the large landslide reactivated by the 23 November 1980 earthquake that destroyed a large sector of the historical centre. The site has been investigated by two ground-monitoring campaigns, the analysis of which allowed identification of the evolution of landslide activity over time. Furthermore, differential SAR interferometry (DInSAR), based upon two different approaches, allowed us to produce point-wise and wide area deformation maps after processing data sets of Earth Resource Satellite 1/2 (ERS-1/2) images, respectively acquired in 1992–2001 and 1992–1995. The results obtained from this analysis highlighted the potentiality of remote-sensing tools in landslide hazard assessment and led to development of a research project based on the installation of corner reflectors along unstable slopes and aimed at creating a field–Earth observation monitoring system.

LiDAR and hyperspectral analysis of mineral alteration and faulting on the west side of the Humboldt Range, Nevada

In order to evaluate the setting of the Humboldt–Rye Patch geothermal field, we carried out a program of hyperspectral and light detection and ranging (LiDAR) imaging of the Humboldt River basin to test (1) whether fault patterns, surface mineral alteration, and mud volcanoes in the Humboldt–Rye Patch district offer the potential for additional geothermal exploration sites; (2) whether mud diapirism in this region could be caused by seismic shaking; and (3) whether significant improvements in exploration can be made using these remote-sensing tools in addition to the more traditional techniques. In the southern (Rye Patch) region, a set of faults cuts the surface of the alluvial fans, and several faults cut shorelines of Lake Lahontan. These shorelines lie at an elevation of 1290 m, which corresponds with the elevation of the Lake 12,500 ± 500 yr ago. We find no signs of surface mineral alteration in the Rye Patch area in spite of the existence of these faults and known alteration at depth. Farther north, in the Humboldt House region, we find abundant evidence of alteration products, including siliceous sinter, carbonate, montmorillonite, hematite, and jarosite. This alteration is widespread, and corresponds to young faulting in only one location. The LiDAR data show at least two mud volcanoes and a large field of low-carbonate mounds. Some of these (apparently) diapiric features may have been associated with seismicity, and both active and paleoseismic events would have been sufficiently close and energetic to have initiated liquefaction in this region. Such liquefaction events would have been more likely, however, during the high stands of Lake Lahontan, when the ground would have been saturated, consistent with reported ages on rocks correlated with the carbonate mounds. We propose further geothermal exploration based on these results.

Utilization of Landsat ETM+ data for mineral-occurrences mapping over Dalma and Dhanjori, Jharkhand, India: an Advanced Spectral Analysis approach

The Advanced Spectral Analysis (ASA) technique, one of the most advanced remote-sensing tools, has been used as a possible means of identifying mineral occurrences over Dalma and Dhanjori. The ASA technique is a sixfold tool, which includes the continuous processes of (1) the reflectance calibration of Landsat Enhanced Thematic Mapper (ETM+) images of the study area, (2) the generation of minimum noise fraction (MNF) transformation, (3) the calculation of the pixel purity index (PPI), (4) the n-dimensional visualization and extraction of endmember spectra, (5) the identification of endmember spectra for mineral occurrences and (6) the mapping of mineral occurrences. The identification of the extracted endmember spectra is obtained by comparing it with available pre-defined library spectra (United States Geological Survey (USGS), John Hopkins University (JHU) and Jet Propulsion Laboratory (JPL) spectral libraries) using the Spectral Analyst tool of ENVI 4.1 software (Research Systems Inc., Boulder, CO, US), which provides scores of matching. Three techniques, namely Spectral Feature Fitting (SFF), Spectral Angle Mapping (SAM) and Binary Encoding (BE), are used for identification of the collected endmember spectra to produce a score between 0 and 1, where the value of 1 equals a perfect match showing the exact mineral type. A total of six endmember spectra are identified and extracted in the study area. Mapping of mineral occurrences is carried out using the Mixture-Tuned Matched Filtering (MTMF) technique over the study area on the basis of collected and identified endmember spectra. Results of the present study using the ASA technique ascertain that Landsat ETM+ data can be used to generate valuable mineralogical information.

Conservation and management implications of nest-site selection of the sympatric crocodilians Melanosuchus niger and Caiman crocodilus in Central Amazonia, Brazil

Management of crocodilians is often based on source-sink dynamics, protecting breeding habitat and concentrating hunting in other areas. Nest distributions shed light on habitat use by breeding populations, which might be used as a basis for monitoring and management. The heterogeneous spatial distribution of Melanosuchus niger and Caiman crocodilus in Amazonia has been suggested to reflect past hunting pressure, often underestimating the natural ecological peculiarities of these species. Ground nest surveys combined with satellite imagery allowed us to evaluate whether nest-site use by M. niger and C. crocodilus reflects environmental constraints or is a result of hunting pressure. Our results indicate that there is little evidence that hunting pressure shapes nest-site use of these species in our study areas. M. niger nests mainly on the shores of stable, temporally impounded floodplain lakes isolated from the early stages of the annual rising water of main rivers. This behavior facilitates the identification of suitable nesting sites using moderate-resolution remote-sensing tools and should guide monitoring efforts and the protection of these areas. In contrast, C. crocodilus is a generalist species, able to nest hundreds of meters inside the forest far from permanent water. This makes the occurrence and distribution of nesting-sites unpredictable using Landsat images. Although nests of this species can be found around lakes where nests of M. niger also occur, the protection of these sites might help to preserve only a small portion of C. crocodilus nesting females. Thus, conservation strategies for C. crocodilus should probably be based on different approaches.

Sandstone reservoir quality prediction: The state of the art

Joanna Ajdukiewicz joined Exxon Production Research Company in 1980. She was Reservoir Quality Assessment and Prediction team lead there from 1991 to 1995 and at Imperial Oil Research Centre in Calgary from 1995 to 1997. Subsequently, she has worked a variety of Exploration Company assignments in the North Sea, Gulf of Mexico, and Middle East. Her current interests are in predicting the distribution of early diagenetic controls on deep reservoir quality. Rob Lander develops diagenetic models for Geocosm LLC. He obtained his Ph.D. in geology from the University of Illinois in 1991, was a research geologist at Exxon Production Research from 1991 to 1993, and worked for Rogaland Research and Geologica AS from 1993 to 2000. He is also a research fellow at the Bureau of Economic Geology. To guess is cheap; to guess wrongly is expensive (Chinese proverb). Reservoir-quality predictive models will be a useful element of risk analysis until remote-sensing tools are invented that accurately measure effective porosity and permeability ahead of the bit. This issue of the AAPG Bulletin highlights recent advances in a new generation of reservoir quality models that have successfully predicted porosity and permeability in diverse siliclastic reservoirs under many different burial conditions. Most previous attempts at predrill reservoir quality prediction have relied on empirical correlations or on first-principle geochemical simulations that incorporate laboratory-derived input parameters (Wood and Byrnes, 1994). The new reservoir quality models differ from previous approaches in that, although incorporating theory-inspired algorithms, they include terms with values that are explicitly designed to be calibrated by, and tested against, data sets of high-quality petrographic analyses that are linked to thermal and effective-stress histories. Petrographic observations therefore provide essential constraints in these models on the types, timing, and rates of key geologic processes affecting sandstone pore systems. This approach avoids the pitfalls inherent …

Flood hazard in Wadi Rahbaa area, Egypt

In the last decade, attention has been devoted to the southern part of the Egyptian Red Sea coast due to the large touristic and mining activities. Egypt spares no effort to develop it, to build new urban communities, and to create new job opportunities. Many comprehensive planning studies have been conducted. Many luxurious tourist spots, airports, and harbors have been constructed. These areas are subjected to flash floods, which represent a frequent threat to these urbanization activities that may cause losses in livelihood. By analyzing the geomorphologic features of the study area, intense stream networks are detected that, with the available metrological data, require flood management and analysis to mitigate the possible negative effects and to benefit from the estimation of flood water. Rahbaa basin is a sub-catchment of wadi Hodin. Flash floods within this area threaten the Red Sea coastal plain as well as the main coastal roads. It also directly drained out to the sea, which leads to a loss of huge amounts of flood water that is useful for arid regions. Using geographic information system and remote-sensing tools with the application of a comprehensive graphical modeling (watershed modeling system) supports the hydrological modeling of HEC-1. The total amount of runoff is calculated and the hydrograph of the 50-year return period is computed using rainfall historical data.

Development and application of a simple hydrologic model simulation for a Brazilian headwater basin

Abstract Physically based hydrologic models for watersheds are important tools to support water resources management and predict hydrologic impacts produced by land-use change. Grande River Basin is located in southern Minas Gerais State, and the Grande River is the main tributary of Basin which has 2080 km 2 draining into the Camargos Hydropower Plant Reservoir (CEMIG — “Minas Gerais State Energy Company”). The objectives of this work were: 1) to create a semi-physically based hydrologic model in semi-distributed to sub-basins approach and based on GIS and Remote Sensing tools and, 2) to simulate the hydrologic responses of the Grande River Basin, thus creating an important tool for management and planning of water resources for region. The hydrologic model is based on the SCS Curve Number (SCS-CN) and MGB/IPH models, and structured into three hydrologic components: estimation of the flow components (quick runoff, hortonian and base flows), propagation into the respective soil reservoirs (surface, sub-surface and shallow saturated zone) and propagation into the channels. Precipitation and discharge data sets were obtained from the Brazilian National Water Agency (ANA). Reference evapotranspiration (ETo) data were obtained from the Brazilian National Meteorological Institute (INMET). In order to estimate actual evapotranspiration, crop coefficient, soil moisture and satellite image interpretation of actual land-use were applied. The long-term hydrologic data series were structured for period between 1990 and 2003. The calibration and validation process was carried out by evaluating the behavior of the Nash–Sutcliffe Coefficient ( C NS ), obtained from three different combinations of calibration and validation years. This allowed us to evaluate the model performance to simulate years in which El Nino (EN) and La Nina (LN) events were registered (1997–1998 and 1999–2000, respectively). The combinations of calibration and validation years were: the first 7 years to calibrate and remaining 6 years to validate; the first 9 years to calibrate and remaining 4 years to validate; and first 11 years to calibrate and the last 2 years to validate. The statistical precision showed that the model was able to simulate the hydrologic impacts, including years of EN and LN events, with C NS scores greater than 0.70 in both situations. The evaluation of the C NS scores showed small variation in the coefficient as the years of validation decreased. In addition, the model was also able to simulate the hydrologic impacts of land-use change in the Grande River Basin, based on the C NS scores of 0.80 for different combinations of validation periods. The hydrologic impacts in Grande River Basin produced from grassland area converted to eucalyptus under three specific scenarios were evaluated, which predicted annual runoff mean reductions of up to 17.8%, due to an increase in evapotranspiration rate for the eucalyptus plantation.

Optimizing Remote Sensing and GIS Tools for Mapping and Managing the Distribution of an Invasive Mangrove (Rhizophora mangle) on South Molokai, Hawaii

In 1902, the Florida red mangrove, Rhizophora mangle L., was introduced to the island of Molokai, Hawaii, and has since colonized nearly 25% of the south coast shoreline. By classifying three kinds of remote sensing imagery, we compared abilities to detect invasive mangrove distributions and to discriminate mangroves from surrounding terrestrial vegetation. Using three analytical techniques, we compared mangrove mapping accuracy for various sensor-technique combinations. ANOVA of accuracy assessments demonstrated significant differences among techniques, but no significant differences among the three sensors. We summarize advantages and disadvantages of each sensor and technique for mapping mangrove distributions in tropical coastal environments.

Lightning-Initiation Locations as a Remote Sensing Tool of Large Thunderstorm Electric Field Vectors

Abstract The lightning data that are recorded with a three-dimensional lightning mapping array (LMA) are compared with data from an electric field change sensor (in this case a flat-plate antenna operated both as a “slow” and a “fast” antenna). The goal of these comparisons is to quantify any time difference that may exist between the initial responses of the two instruments to a lightning flash. The data consist of 136 flashes from two New Mexico thunderstorms. It is found that the initial radiation source detected by the LMA usually precedes the initial response of both the slow and fast antennas. In a small number of cases, the flat-plate antenna response precedes the initial LMA source, but by no more than 2 ms. The observations of such a close time coincidence suggest that the first LMA radiation source of each flash was located at or very near the flash-initiation point. Thus, the first LMA radiation source and the initial sequence of sources from a lightning flash can be used as remote sensing tools to give information about the magnitude of the electric field (relative to lightning-initiation thresholds) and the direction of the electric field at the initiation location.

A fuzzy-possibilistic scheme of study for objects with indeterminate boundaries: application to French Polynesian reefscapes

This communication describes the study of an ecological system using remote-sensing data and image-analysis tools derived from possibility theory. Possibility theory enables the construction of membership functions using a multisource fusion algorithm. The sources of information are the sampled training stations. The authors test to see if the possibilistic algorithm is able to provide results with an accuracy at least equal to that provided by traditional probabilistic-classification algorithms. Then, for each pixel, they analyze the hierarchy of membership degrees output by the fusion to study the spatial structure of an ecosystem composed of objects that lack precise boundaries. They characterize patches or gradients, boundary rates, and transition states. As an example, a scheme of analysis for underwater reefscapes at Moorea Island, French Polynesia, is proposed. The nonparametric multisource fusion method has an accuracy of 82% (overall normalized-percentage agreement), while a probabilistic maximum-likelihood classifier has an accuracy of 73%. The analysis of the hierarchy of membership degrees indicates that almost 25% of Moorea Island lagoon is heterogeneous, composed of real boundaries, transition states, and fragmented zones.

Remote Sensing Tools Assist in Environmental Forensics. Part I: Traditional Methods

This is part one of a two-part discussion, in which we will provide an overview of the use of aerial photography, topographic mapping and photogrammetry in environmental enforcement actions. The visualization of spatial relationships of natural and man-made features can focus the scope of environmental investigation, and provide a simple, yet quantitative, historical record of changes in conditions on a site. Aerial photography has been used in environmental remote sensing since the early part of the 20th century. Aerial photos are valuable tools for environmental assessment because they provide objective, detailed documentation of surface conditions at a specific time. Furthermore, they can generally be obtained even in cases where access on the ground is denied to investigators. From aerial photos, precise quantitative information can be collected using photogrammetry. Such measurement and positional data can be produced in digital format for input into a Geographic Information System (GIS) for computerized analysis and display. Other information derived from aerial photographs requires specialized photointerpretive skills and experience. These include the recognition of vegetation mortality, oil-spill damage, and the ecological quality of water bodies. The location, extent and historical change of hazardous waste sites can be documented on topographic maps. These maps are often created from aerial photographs, and display the extent and location of real-world features by symbolizing them. The major advantage of maps over aerial photos is that maps can show things that are not visible from the air, while omitting unnecessary and distracting information. Because maps are derived products, they may contain bias in content and presentation, and they must be backed up by careful documentation and quality assurance protocols.

The Geography of Fish: The Use of Remote Sensing and Spatial Analysis Tools in Fisheries Research

Rather than seeing the oceans as an expansive void, researchers using acoustic technologies can detect the heterogeneity of biological resources and view the marine environment as a three-dimensional landscape. Underwater remote sensing, using acoustics, provides high resolution maps of the spatial distribution of organisms in aquatic ecosystems. Analyzing the spatial pattern of species distribution within the water column and the impact of that organization on ecological processes bridges the fields of fisheries and spatial analysis. Tools and concepts familiar to geographers, such as remote sensing, GIS, and landscape ecology, contribute to the investigation of large lake and marine ecosystems.