Remote Imagery Research Articles

Nitrate pollution of surface water induced by agricultural non-point pollution in the Pocochay watershed, Chile

Diffuse nitrogen pollution caused by irrigated agriculture is quantified for the Pocochay stream located in the Aconcagua watershed in the Valparaíso region, Chile. The study area has an extent of 93 km 2 with 36 km 2 under irrigation. It is representative for the central part of Chile where intensive irrigation is prevailing and predominantly taking place in the alluvial plains of river systems with water sources from the Andes Mountains. Water quality and discharge were monitored biweekly at several points of the Pocochay main stream from December 2003 to June 2006. The study was supported by an agricultural survey and remote imagery interpretation in order to retrieve data on cropping pattern and actual fertilizer uses in the sub-watersheds. Nitrate – N concentration in the Pocochay stream ranged from 1.3 to 10.1 mg L −1 with a mean of 4.8 mg L −1. Other nitrogen species showed very low concentrations. At average, around 52 kg N ha −1 a −1 are drained from the study area as compared to 167 kg N ha −1 a −1 applied as fertilizer to the fields. Even though nitrate concentrations in the Pocochay do not reach alarming levels yet, the impact of irrigated agriculture on surface water quality is obvious and makes a case for introducing best management practices to avoid aggravation of contamination.

COMBINING SENSORS IN LANDSCAPE ECOLOGY: IMAGERY-BASED AND FARM-LEVEL ANALYSIS IN THE STUDY OF HUMAN-DRIVEN FOREST FRAGMENTATION

Although remote sensed methods provide reliable basis for identifying the amount and spatial configuration of deforestation, they cannot solely explain its underlying causes. For that, we need to complement the imagery analysis with socio-economic data from household or farm-level studies, because these domestic units affect process such migration, land-use, and technology choice. Thus, by combining remote imagery sensor and social survey, we obtain a merged analytical framework, which has the potential to improve our understanding on the determinants of human-driven forest fragmentation. We present such a methodological framework for studying deforestation in the Brazilian Atlantic Forest. Two empirical studies - a remote sensing analysis and a farm-level survey - were put together in the context of a wider project focusing on forest fragmentation process in the northeastern Guanabara region, Rio de Janeiro, Brazil. We show that, rather than 'patchwork quilt' methodologies, we need theoretical-oriented frameworks that give sense to the use of different landscape ecological approaches and methods (imagery analysis, mathematical modeling and social studies) in order to document and interpret land-use changes. 
 Key-words: remote sensing; farm-level survey; landscape research methodology; forest fragmentation; Brazilian Atlantic Forest.

Pyrogenic carbon emission from a large wildfire in Oregon, United States

We used a ground‐based approach to compute the pyrogenic carbon emissions from the Biscuit Fire, an exceptionally large wildfire, which in 2002 burned over 200,000 ha of mixed conifer forest in southwestern Oregon. A combination of federal inventory data and supplementary ground measurements afforded the estimation of preburn densities for 25 separate carbon pools at 180 independent locations in the burn area. Average combustion factors for each of these pools were then compiled from the postburn assessment of thousands of individual trees, shrubs, and parcels of surface and ground fuel. Combustion factors were highest for litter, duff, and foliage, lowest for live woody pools. Combustion factors also increased with burn severity as independently assessed from remote imagery, endorsing the use of such imagery in scaling emissions to fire area. We estimate the total pyrogenic carbon emissions from the Biscuit Fire to be between 3.5 and 4.4 Tg C (17 and 22 Mg C ha−1) depending on uncertainty in our ability to estimate preburn litter pools and mineral soil combustion with a central estimate of 3.8 Tg C (19 Mg C ha−1). We estimate that this flux is approximately 16 times the annual net ecosystem production of this landscape prior to the wildfire and may have reduced mean net biome production across the state of Oregon by nearly half in the year 2002.

Combining sensors in landscape ecology: imagery-based and farm-level analysis in the study of human-driven forest fragmentation

Although remote sensed methods provide reliable basis for identifying the amount and spatial configuration of deforestation, they cannot solely explain its underlying causes. For that, we need to complement the imagery analysis with socio-economic data from household or farm-level studies, because these domestic units affect process such migration, land-use, and technology choice. Thus, by combining remote imagery sensor and social survey, we obtain a merged analytical framework, which has the potential to improve our understanding on the determinants of human-driven forest fragmentation. We present such a methodological framework for studying deforestation in the Brazilian Atlantic Forest. Two empirical studies a remote sensing analysis and a farm-level survey were put together in the context of a wider project focusing on forest fragmentation process in the northeastern Guanabara region, Rio de Janeiro, Brazil. We show that, rather than `patchwork quilt' methodologies, we need theoretical-oriented frameworks that give sense to the use of different landscape ecological approaches and methods (imagery analysis, mathematical modeling and social studies) in order to document and interpret land-use changes.

Geologic, geomorphic, and meteorological aspects of debris flows triggered by Hurricanes Frances and Ivan during September 2004 in the Southern Appalachian Mountains of Macon County, North Carolina (southeastern USA)

In September 2004, rain from the remnants of Hurricanes Frances and Ivan triggered at least 155 landslides in the Blue Ridge Mountains of North Carolina. At least 33 debris flows occurred in Macon County, causing 5 deaths, destroying 16 homes, and damaging infrastructure. We mapped debris flows and debris deposits using a light-detecting and ranging digital elevation model, remote imagery and field studies integrated in a geographic information system. Evidence of past debris flows was found at all recent debris flow sites. Orographic rainfall enhancement along topographic escarpments influenced debris flow frequency at higher elevations. A possible trigger for the Wayah and fatal Peeks Creek debris flows was a spiral rain band within Ivan that moved across the area with short duration rainfall rates of 150–230 mm/h. Intersecting bedrock structures in polydeformed metamorphic rock influence the formation of catchments within structural–geomorphic domains where debris flows originate.

Commercial satellite imagery: CI, KM, and trade secret law

PurposeThe purpose of this paper is to examine the implications of remote surveillance or satellite imagery as they relate to trade secret law, knowledge management, and competitive intelligence.Design/methodology/approachThe paper approaches legal issues from the perspective of a trade secret holder.FindingsWhile conducting research for this paper, it was found that, while technological improvements relating to satellite imagery and remote sensing are increasingly more precise and ubiquitous, the laws protecting businesses that have an interest in protecting trade secrets are inconsistent. On the one hand, the US Government has given itself a powerful tool to protect trade secrets under the Economic Espionage Act. On the other hand, the Government has granted remote satellite companies licences under which they may sell satellite images to industrial competitors, consequently thwarting trade secret protection effortsOriginality/valueTrade secrets represent a valuable contribution to a nation's economy, particularly when some interventions do not meet the requirements necessary for more traditional intellectual property regime protection (e.g. copyright, trade mark, patents). A trade secret's value lies in it remaining hidden. There are few cases addressing trade secrets and satellite imagery. The stalwart case, E.I. duPont deNemours & Co., Inc. v. Rolfe Christopher, represents a tentative foray into the subject, but only suggests the rights a trade secret holder may have when a commercial satellite company collects otherwise innocuous data and sells those to a competitor. A proper plaintiff to test the boundaries surrounding trade secret law, satellite imagery, and competitive intelligence remains at large.

Evolution of the modern Nile delta promontories: development of accretional features during shoreline retreat

The active accretional features that have developed along the modern Nile Delta promontories during shoreline retreat are analysed using topographic maps, remote imagery, ground and hydrographic surveys, together providing 15 time-slice maps (1922–2000) at Rosetta and 14 time-slice maps (1909–2000) at Damietta. Small double sandy spits developed and persisted at Rosetta between 1986 and 1991. At Damietta, a much larger single spit, 9 km long, formed approximately east of the mouth of the Damietta Nile branch between 1955 and 1972, although its source has now been depleted. Both the Rosetta and Damietta inlets are associated with submerged mouth bars that accumulated prior to the damming of the Nile, but that continue to contribute to local sedimentation problems, particularly at Rosetta. The development of the active accretional features along the Nile promontories reflects a combination of factors including sediment availability, transport pathways from source areas, a decrease in the magnitude of Nile flood discharges, as well as the impact of protective structures at the river mouths.

Hydrocarbon occurrence and exploration in and around igneous rocks

Abstract Hydrocarbons can occur within and around igneous rocks, sometimes in commercially significant quantities. Igneous or closely associated rocks can be hydrocarbon sources in the conventional sense (biotic) as well as possibly through abiotic processes. Maturation is extremely variable, depending on the extrusive/intrusive nature of the activity and the relative importance of a deep heat source. Igneous volatiles and hydrothermal fluids may also be important in mobilizing and moving hydrocarbons. Igneous rocks can have good reservoir qualities, and they can produce their own trapping structures as well as being part of a larger feature. Many exploration methods are individually unreliable in and around igneous rocks, and an integrated approach is most effective. Seismic, magnetotelluric, gravity and magnetic surveys may all provide helpful information. Geological mapping, geochemistry and remote imagery may also be helpful. Evaluation of potentially commercial hydrocarbon accumulations requires interpretation of well logs, which may have unusual characteristics. Drill stem and production tests may also be needed for evaluation before exploration ends and development begins.

Patterns and processes in a seasonally flooded tropical plain: the Apure Llanos, Venezuela

AimThe factors and processes determining the ecology and distribution of ecosystems in the Apure lowlands, Venezuela, are critically discussed.LocationThe Middle Apure region, an alluvial Quaternary plain built by the Arauca and Apure rivers, occupies a subsidence area caused by faulting of the geological basement during the last and most active phases of the Andean uplift.MethodsTo assess the determinants of the hydrological and ecological variability in this region, we used remote imagery and field surveys.ResultsThe hydrological and ecological variability responds to a set of interconnected processes of different nature: geological, climatic and paleoclimatic and hydrographic, which together have conditioned the geomorphological history of the regional landscape. This evolution, in turn, has guided the soil forming processes and the functional behaviour of the different types of savanna, forest and wetland ecosystems. The continuously subsiding trend of the Llanos that accompanied the Andean Orogeny, together with the Quaternary climatic oscillations, settled the framework in which successive depositional and erosional events took place. Five Quaternary depositional events, gave rise to the actual landscape pattern. The youngest, Q0a is the actual flood plain, Q0b is the Holocene flood plain, Q1 is from Upper Pleistocene, Q2 from Middle Pleistocene, while Q3 the oldest sedimentary material in this area, is of Lower Pleistocene age. Within each sedimentary unit, we analysed the pattern of land forms, soils and natural ecosystems. The Q0 and Q1 land units show a characteristic unstable drainage system, with frequent changes in the course of rivers and their affluents and diffluents. Soil genesis mainly correlates with the contrasting characteristics of the wet and dry tropical climate, and with the water regime of each land form on each sedimentary unit. So, a sequence from entisols, through inceptisols and alfisols, to ultisols, correlates with the sequence of land units from Q0 to Q3. Different vegetation types predominate on each land form/soil unit. Gallery forest (evergreen and semi‐evergreen) exclusively occurs on Q0a entisols, semi‐deciduous forest characterizes Q0b and Q1 inceptisols, semi‐seasonal savanna is almost entirely restricted to Q0 and Q1 units, hyperseasonal savanna widely dominates on Q2 and Q3 alfisols and ultisols, while seasonal savanna just occurs on the well‐drained Q1 and Q2 alfisols, and on dunes.Main conclusionsThe genesis and dynamics of the various land forms and soils throughout the Quaternary, provide the key to their particular hydrology, and determines the kind of plant formation able to occupy each habitat, thus explaining the complex pattern of quite different ecosystems found in the region.

Coastline Registration: Efficient Optimization in Large Dimensions Using Genetic Algorithms

Registration of remote imagery underpins a number of important applications in 'remote sensing' including mosaicing, sensor fusion, temporal change detection and integration with GIS databases. Accurate and automatic methods of establishing dense correspondences between images are vital given the increasing volume of high resolution imagery available. An explicit 'structural matching' framework is presented derived from the experience in the wider computer vision community of matching in a variety of domains including stereopsis, motion and object recognition. Match constraints can be combined within an optimization framework enabling the exploitation of a variety of minimization techniques. In this work, a multi-resolution representation of coastline contours is used to enable matching to handle very large scale difference between images, and to reduce the dimensionality of the match problem. Nonetheless, the resultant optimization problem remains huge and highly non-convex necessitating the use of 'genetic algorithms' to recover accurate correspondences.

The Study of Improved CP Neural Network for Remote Sensing Classification

The study improves the CP neural network including the weight vectors initial, network learning, the competitive nodes dynamic allocation and the vigilance parameter design etc. It applied to the remote sensing imagery classification. The learning times influence the node numbers and learning accuracy. According its raise, the learning accuracy increases a limit degree.The research boundary is decided by the vigilance parameter , which decreases with the learning process in order to get the high accuracy and the stability of networks. The two\|layer networks improves the overall accuracy by 1.1%, Kappa coefficient by 0.02, which compared to the single\|layer networks. It is concluded the improved CP is another classification method for remote sensing.

Using dendronal signatures for feature extraction and retrieval

AbstractA dendrone is a hierarchical thresholding structure that can be automatically generated from a complex image. The dendrone structure captures the connectedness of objects and subobjects during successive brightness thresholding. Based on connectedness and changes in intensity contours, dendronic representations of objects in images capture the coarse‐to‐fine unfolding of finer and finer detail, creating a unique signature for target objects that is invariant to lighting, scale, and placement of the object within the image. Subdendrones within the hierarchy are recognizable as objects within the picture. Complex composite images can be autonomously analyzed to determine if they contain the unique dendronic signatures of particular target objects of interest. In this paper, we describe the initial design of the dendronic image characterization environment (DICE) for the generation of dendronic signatures from complex multiband remote imagery. By comparing subdendrones within an image to dendronic signatures of target objects of interest, DICE can be used to match/retrieve target features from a library of composite images. The DICE framework can organize and support a number of alternative object recognition and comparison techniques, depending on the application domain. © 2001 John Wiley & Sons, Inc. Int J Imaging Syst Technol 11, 243–253, 2000

Spatial relationships of Adélie penguin colonies: implications for assessing population changes from remote imagery

The relationship between colony area and population density of Adélie penguins Pygoscelis adeliae was examined to determine whether colony area, measured from aerial or satellite imagery, could be used to estimate population density, and hence detect changes in populations over time. Using maps drawn from vertical aerial photographs of Adélie penguin colonies in the Mawson region, pair density ranged between 0.1 and 3.1 pairs m−2, with a mean of 0.63 ± 0.3 pairs m−2. Colony area explained 96.4% of the variance in colony populations (range 90.4–99.6%) for 979 colonies at Mawson. Mean densities were not significantly different among the 19 islands in the region, but significant differences in mean pair density were observed among colonies in Mawson, Whitney Point (Casey, East Antarctica) and Cape Crozier (Ross Sea) populations. The relationship between colony area and population may be locality-and/or species-specific, and a robust data set is required to validate the relationship.

Multialtitude airborne observations of insolation effects of forest fire smoke aerosols at BOREAS: Estimates of aerosol optical parameters

Forest fire disturbance, as part of the natural cycle of the boreal ecosystem renewal, proved a significant factor in the acquisition scheduling of optical remote imagery at the northern study site of the Boreal Ecosystem‐Atmosphere Study (BOREAS), conducted in northern/central Canada during the July/August months of 1994. One such episode, between July 28 and 31, was due entirely to smoke transported over the study site from nearby and distant downwind fires. Noon insolation was reduced from 800 W/m2 on July 28 to 680 W/m2 on July 31 and incident PAR radiation from 320 to 250 W/m2. During the July 31 smoke episode the compact airborne spectrographic imager (CASI) was flown at 150, 300, 900, 1500, and 3200 m agl over a forested site, while measuring the scene‐reflected radiance as well as upwelling and downwelling irradiances in the spectral range 403 and 916 nm (2.5 nm resolution). These multialtitude observations of upwelling and downwelling irradiance and the hemispherical reflectance are used to estimate at two wavelengths, 550 and 672 nm, the vertical profiles of aerosol optical depth, attenuation coefficient, and single‐scattering albedo representative of the smoke aerosols encountered at BOREAS. For smoke aerosols from distant fires (high altitude) the single‐scattering albedo was 0.9 and the attenuation coefficient was 0.32 km−1 at 672 nm, whereas for smoke aerosols from nearby fires, values of 0.6 and 0.60 km−1 were found. This is qualitatively consistent with differences expected for distant primarily sulfate aerosols and higher soot aerosols for nearby flaming fires.

Property fields in an effluent plume of the Mississippi river

Surface property distributions were mapped in the Mississippi River plume during May and August 1993 while following surface drifters. Prevailing winds were the primary factor controlling the orientation of the plume. In May, under typical southeasterly winds, the plume turned anticyclonically towards the coast, while in August, under anomalous westerly winds, the plume turned east. Remote imagery of sea surface temperature and suspended sediments confirmed the direction of the plume. Optimally interpolated maps of surface salinity, temperature, chlorophyll a fluorescence, and transmissivity from underway sampling, and periodic nutrient samples, reveal the plume structure. In May concentrations of nitrate, silicate, and phosphate decreased linearly with increasing salinity. Chlorophyll a increased to peak concentrations of 10 μg 1 −1 in the plume, although higher pigment biomass was observed near the coast. In August nitrate and silicate concentrations decreased conservatively near the mouth of SW Pass, except where pigment biomass was enhanced in a convergent surface front. Surface nutrient concentrations in the plume also decreased with increasing salinity. The observations provide the first Lagrangian view of surface property distributions in the Mississippi River plume, and indicate that significant temporal variability exists in physical and biological properties within a day after waters are discharged from the river delta.

A REVIEW OF THE U.S. TIGHT GAS INDUSTRY FROM THE PERSPECTIVE OF SELECTED AUSTRALIAN AND NEW ZEALAND BASINS

The recovery of natural gas from low permeability sandstones in the US has been made commercially possible due, to a large degree, to advanced technologies. The US currently produces 2 TCF annually from tight gas sandstone reservoirs. Large efforts have been directed towards identifying and developing the more productive basinal areas, or 'sweet spots9 of tight gas reservoirs. The identification of natural fractures prior to drilling, through the use of remote imagery in combination with established methods such as magnetic and gravity mapping, is currently being pioneered. Reduction in well-bore stimulation costs through development and application of advanced hydraulic fracture technology has improved the economics of tight gas production. The use of 3D fracture models in combination with realistic insitu stress profiles, appropriate proppants and effective quality controls have greatly increased well productivities through smaller, more efficient fracture treatments. Treatments have been successfully designed to avoid damage to natural fractures.Large tight gas sandstone resources similarly exist in the Cooper and Perth Basins of Australia and in the Taranaki Basin of New Zealand, although these resources remain largely untapped. To date, less than 50 BCF has been produced from Australian and New Zealand tight sandstones, largely from the Tirrawarra Sandstone and Patchawarra Formation of the Cooper Basin and the Ngatoro/McKee Formations of the Taranaki Basin. These formations compare well however, in terms of depositional environments with prolific US tight gas producing formations. They appear to be well placed to take advantage of the experiences and technologies gained by their US counterparts as well as through site specific adaptation of such technologies and the development of new technologies.

Rotation of the Chortís block causes dextral slip on the Guayape fault

The Chortís block is undergoing deformation as a direct result of large‐magnitude sinistral strike‐slip faulting on the North America‐Caribbean plate boundary. We have studied the Chortís block using geologic mapping, remote imagery, and earthquake seismology to evaluate the effect that large‐magnitude strike‐slip faulting has on an adjacent microcontinental block. In the eastern part of the Chortís block, recent geologic mapping has shown that the northeast striking Guayape fault is dextral instead of sinistral as previously assumed. Because this is a major fault that cuts most of the Central America isthmus, the new evidence for dextral slip necessitates a reinterpretation of the active tectonics of the Chortís block. The presence of several north trending rifts in the western part of the Chortís block has led previous workers to propose that the Chortís block is divided into smaller, independently rotating blocks. We use earthquake seismology and remote imagery data to extend this interpretation to the central portion of the Chortís block. However, we have modified their model to account for dextral slip on the Guayape fault. We believe that rotation of the Chortís block causes dextral slip on the Guayape fault even though Central America is undergoing large sinistral displacement with respect to North America.

Microalgal Pigment Assessments Using High-Performance Liquid Chromatography: A Synopsis of Organismal and Ecological Applications

Past and current efforts at identifying microalgal phylogenetic groups rely largely on microscopic evaluation, which requires a high level of taxonomic skill, may take considerable time, can be variable among personnel, and does not allow characterization of the physiological status of the taxa. High-performance liquid chromatography (HPLC) has proven effective in rapidly separating and distinguishing chlorophylls, chlorophyll-degradation products, and carotenoids within monotypic and mixed algal samples. When coupled with absorbance and/or fluorescence spectroscopy, HPLC can accurately characterize phylogenetic groups and changes in community composition and yield information concerning microalgal physiological status, production, trophic interaction, and paleolimnology/paleooceanography. The recent widespread occurrence of toxic and noxious phytoplankton blooms has necessitated the use of remote imagery of pigment and reflectance "signatures" for monitoring and predicting bloom distribution. Because HPLC allows the processing of large numbers of samples from numerous locations relatively quickly, it is ideally suited for large-scale "ground truthing" of remotely sensed imagery. Coupled with rapidly evolving computer-based remote sensing technologies, HPLC-based pigment analyses may provide accurate assessments of aquatic biogeochemical flux, primary production, trophic state, water quality, and changes therein on local, regional, and global scales.

Cross‐Scale Morphology, Geometry, and Dynamics of Ecosystems

Community ecology and ecosystem ecology seem to have existed in different worlds. Levin (1989) suggests that the gulf between the two is the consequence of the different historical traditions in each. Community ecology, for example, emerged from basic studies, where generalized patterns were sought in the natural interactions among the biota. From the outset, the goal has been to deduce general and simple theory. On the other hand, many of the modelling approaches developed to understand ecosystem dynamics emerged from specific applied problems, where not only biotic but abiotic and human disturbances transformed ecosystem function. That tradition, therefore, is often more complete, but at the price of producing a collection of complex specific examples from which generalization is difficult.

Engineering Geology and Military Operations: An Overview with Examples of Current Missions

Geological investigations in support of military ground operations are intelligence functions which may be categorized as either combat or engineer , and which are related to either tactical or construction operations. Combat intelligence includes the evaluation of geological terrain data such as slope, relief, and soil/rock type, whereas engineer intelligence involves mobility and countermobility operations, sources of construction materials, water supply, camouflage and deception, and siting of facilities. In tactical situations, these intelligence functions are performed cooperatively by troops of two separate U.S. Army Branches, Military Intelligence (MI) and Corps of Engineer (EN) troops at the command echelon of Theater Army, and at its subordinate commands, Corps, and Division. Military Intelligence units have the capability to evaluate remote imagery such as panchromatic aerial photography, multispectral scanner, thermal infrared, and side-looking airborne radar, as well as data derived from passive battlefield geophysical sensors. These evaluations are generally directed toward locating enemy troop and weapons concentrations, as opposed to the analysis of geological data for construction purposes. Most geological information pertinent to both combat and engineer intelligence is collected and evaluated by Engineer troops in Terrain Teams which are part of Topographic Battalions. Engineer intelligence is generally presented to Engineer units in technical report format; combat intelligence, on the other hand, is delivered to tactical commanders in the semi-technical formats of map or photomosaic overlays. Most of the applied geoscience research activities are conducted at Corps of Engineer laboratories and include underground construction, tunnel detection, tactical hydrology, ground-water exploration, hazardous-waste site mitigation, and mobility and countermobility evaluations. All of these activities have civilian applications. As applied military research, the general goal is to increase the mobility and survivability of friendly forces and to decrease the effectiveness of numerically superior enemy forces. Considerable potential defensive advantages have been developed through innovative applied geoscience research. These advantages are largely untested during wartime conditions, but they remain in current American national defense strategy, and will continue so throughout the final quarter of the Twentieth Century.