Water budget and vertical conductance for Lowry (Sand Hill) Lake in north-central Florida, USA     

Louis H. Motz  Gregory D. Sousa  Michael D. Annable 《Journal of Hydrology》2001,250(1-4):134-148

Water-budget components and the vertical conductance were determined for Lowry (Sand Hill) Lake in north-central Florida, USA. In this type of lake, which interacts with both the surface-water and groundwater systems, the inflow components are precipitation, surface-water inflow, groundwater inflow, and direct runoff (i.e. overland flow), and the outflow components are evaporation, groundwater outflow, and surface-water outflow. In a lake and groundwater system that is typical of many karst lakes in Florida, a large part of the groundwater outflow occurs by means of vertical leakage through an underlying confining unit to a deeper, highly transmissive aquifer called the upper Floridan aquifer. The water-budget component that represents vertical leakage to the upper Floridan aquifer was calculated as a residual using the water-budget equation. For the 13 month period from August 1994 to August 1995, relative to the surface area of the lake, rainfall at Lowry Lake was 1.55 m yr⁻¹, surficial aquifer inflow was 0.79 m yr⁻¹, surface-water inflow was 1.92 m yr⁻¹, and direct runoff was 0.01 m yr⁻¹. Lake evaporation was 1.11 m yr⁻¹, and surface-water outflow was 1.61 m yr⁻¹. The lake stage increased 0.07 m yr⁻¹, and the vertical leakage to the upper Floridan aquifer was 1.48 m yr⁻¹. Surficial aquifer outflow from the lake was negligible. At Lowry Lake, vertical leakage is a major component of the water budget, comprising about 35% of the outflow during the study period. The vertical conductance (K_V/b), a coefficient that represents the average of the vertical conductances of the hydrogeologic units between the bottom of a lake and the top of the upper Floridan aquifer, was determined to be 2.51 × 10⁻⁴ day⁻¹ for Lowry Lake.  相似文献   

Submarine pits of the azores plateau     

Frederico Machado 《Bulletin of Volcanology》1959,21(1):109-116

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On the numerical simulation of waterflooding of heterogeneous petroleum reservoirs     

Jim Douglas Jr.  Frederico Furtado  Felipe Pereira 《Computational Geosciences》1997,1(2):155-190

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Application of geostatistical methods in gold geochemical anomalies identification (Montemor-O-Novo, Portugal)   总被引：1，自引：0，他引：1  

A. P. Reis  A. J. Sousa  E. Cardoso Fonseca 《Journal of Geochemical Exploration》2003,77(1):45-63

The study described herein concerns the application of geostatistical methods to data soil from Montemor-O-Novo area (Southern Portugal). In the area, the gold mineralised zones (Banhos, Caeiras, Falés, Gamela, Malaca and Monfurado) are characterised by different geological settings and mineralogical assemblages. A total of 1211 soil samples were collected in Montemor-O-Novo area and analysed for Cu, Pb, Zn, As, Ba and Au by atomic absorption spectrometry.To account for spatial structure, simple and cross variograms were computed for the main directions of the grid sampling. From the experimental variograms a linear model of coregionalization composed of three structures, a nugget effect and two anisotropic spherical structures, was fitted to each of the six variables. The coregionalization matrices deduced from the theoretical model show the relationships between the variables at different scales. These matrices were compared with those obtained by principal component analysis (PCA).This methodology was the basis for estimating the corresponding spatial components (Y0, Y1 and Y2) using factorial kriging analysis (FKA). Maps of raw data, Y0, Y1 and Y2 were made for each variable.The use of multivariate analysis permit the study of the spatial structure intrinsic to geochemical data and the identification and refinement of significant anomalies related to Au-bearing mineral deposits.  相似文献   

Using Ontologies for Integrated Geographic Information Systems   总被引：13，自引：0，他引：13  

Frederico T. Fonseca  Max J. Egenhofer  Peggy Agouris  & Gilberto Câmara 《Transactions in GIS》2002,6(3):231-257

Today, there is a huge amount of data gathered about the Earth, not only from new spatial information systems, but also from new and more sophisticated data collection technologies. This scenario leads to a number of interesting research challenges, such as how to integrate geographic information of different kinds. The basic motivation of this paper is to introduce a GIS architecture that can enable geographic information integration in a seamless and flexible way based on its semantic value and regardless of its representation. The proposed solution is an ontology-driven geographic information system that acts as a system integrator. In this system, an ontology is a component, such as the database, cooperating to fulfill the system's objectives. By browsing through ontologies the users can be provided with information about the embedded knowledge of the system. Special emphasis is given to the case of remote sensing systems and geographic information systems. The levels of ontologies can be used to guide processes for the extraction of more general or more detailed information. The use of multiple ontologies allows the extraction of information in different stages of classification. The semantic integration of aerial images and GIS is a crucial step towards better geospatial modeling.  相似文献   

The use of GPR for characterizing underground weathered profiles in the sub-humid tropics     

Paulo Roberto Antunes Aranha  Cristina Helena Ribeiro Rocha Augustin  Frederico Garcia Sobreira   《Journal of Applied Geophysics》2002,49(4)

Ground penetrating radar (GPR) has been used as a tool to access information about ground subsurface features. Such information is very important for different types of studies, varying from those related to archeological research to those studying geological elements of bedrock. More recently, however, GPR has been increasingly applied to environmental studies, especially for soil research. This paper presents the results of an application of GPR for the study of weathered profiles. GPR was used to discover the degree of trustworthiness of the information on the ground subsurface through the interpretation of the results of the radar sections as well as the data collected from boreholes, which reached until 21 m. The results show a relatively high degree of details obtained by GPR, indicating the possibility of speeding up ground subsurface surveys related to geomorphological, geological, and pedological studies.  相似文献   

Photometric Study of Comet C/2014 S2 (PANSTARRS) After the Perihelion     

A. S. Betzler  O. F. de Sousa  L. B. S. Betzler 《Earth, Moon, and Planets》2018,122(1-2):53-71

We analyzed the BVR photometry of comet C/2014 S2 obtained between March and June 2016, in observatories installed in Europe and the United States. Using the Lomb–Scargle periodogram, we found that the most probable periodicity deduced from the V-band magnitudes is 2.70 days, suggesting that it is the period of rotation of the nucleus of this comet is \(2.70 \pm 0.07\) days or \(68 \pm 2\) h, with a peak-to-peak light curve amplitude of \(0.4 \pm 0.1\) magnitudes. We verify that the absolute magnitude \(H_0\) and the activity index n differ from each other when they are calculated from the visual or CCD magnitudes. Considering the absolute magnitude \(H_{v0}=\) 6.0, obtained from visual magnitudes, we estimate that the lower limit of nuclear radius is 1.3 km. Analyzing the variation of magnitude R with the photometric aperture, we suggest that the coma of this object was in steady-state within the time limits of our observational interval. The coma had a mean color index B–V\(=0.79\pm 0.22\), which is typical of active comets. Additionally, we have shown that the use of a variable photometric aperture, linked to geocentric distance, is probably unnecessary for the comet PANSTARRS .  相似文献   

On the treatment of uncertainty in seismic vulnerability and portfolio risk assessment          下载免费PDF全文

Luis Sousa  Vitor Silva  Mário Marques  Helen Crowley 《地震工程与结构动力学》2018,47(1):87-104

In a related study developed by the authors, building fragility is represented by intensity‐specific distributions of damage exceedance probability of various damage states. The contribution of the latter has been demonstrated in the context of loss estimation of building portfolios, where it is shown that the proposed concept of conditional fragility functions provides the link between seismic intensity and the uncertainty in damage exceedance probabilities. In the present study, this methodology is extended to the definition of building vulnerability, whereby vulnerability functions are characterized by hazard‐consistent distributions of damage ratio per level of primary seismic intensity parameter—Sa(T₁). The latter is further included in a loss assessment framework, in which the impact of variability and spatial correlation of damage ratio in the probabilistic evaluation of seismic loss is accounted for, using test‐bed portfolios of 2, 5, and 8‐story precode reinforced concrete buildings located in the district of Lisbon, Portugal. This methodology is evaluated in comparison with current state‐of‐the‐art methods of vulnerability and loss calculation, highlighting the discrepancies that can arise in loss estimates when the variability and spatial distributions of damage ratio, influenced by ground motion properties other than the considered primary intensity measure, are not taken into account.  相似文献   

Spatiotemporal variability of vegetation due to drought dynamics (2012–2017): a case study of the Upper Paraíba River basin,Brazil     

Ferreira da Silva  Glauciene Justino  de Oliveira  Nádja Melo  Santos  Celso Augusto Guimarães  da Silva  Richarde Marques 《Natural Hazards》2020,102(3):939-964

Natural Hazards - Vegetation indices have been widely used for monitoring the spatiotemporal variables of vegetation and characterizing droughts, primarily in semiarid regions. Drought is a...  相似文献   

Geographical ecology of the symbiotic crabs Libinia ferreirae and Libinia spinosa: Distributional patterns in south and south-eastern coast of Brazil     

Geslaine Rafaela Lemos Gonçalves  Luana Ferraz da Silveira Palomares  Aline Nonato Sousa  Gilson Stanski  Gustavo Sancinetti  Rogerio Caetano da Costa  Antonio Leão Castilho 《Marine Ecology》2020,41(4):e12606

The Brazilian coast is home to two species of Majoid crabs: Libinia ferreirae and Libinia spinosa, with similar habits, as they live in symbiosis with the jellyfish Lychnorhiza lucerna during their juvenile stage and dwell on the bottom of the ocean near the coast when adults. This study investigated the spatial and temporal distribution of L. ferreirae and L. spinosa during different ontogenic phases on the south and south-eastern coast of Brazil, between latitudes 22º and 27ºS. Our results showed that both species have different distributions during their development in the three studied regions. Libinia ferreirae were more abundant associated with jellyfish, and L. spinosa were more abundant in the free-living phase. Environmental factors, especially temperature and salinity, for associated and free-living crabs, respectively, are the main factors that need to be supported for the establishment of these specimens. We were able to identify that the presence or absence of hosts (given the ecological interactions between the species) is determinant in finding the associated crabs. Geographical variations (morphology of the regions, marine currents and the strength of the tide) are linked directly to the movement of the jellyfish hosts to the coast, influencing the abundance of L. fereirae and L. spinosa populations and affecting their distribution patterns. We can infer that both species are connected with other populations because of the association with the jellyfish, crabs could be passively transported along the south and south-eastern coast of Brazil, maintaining the connection between metapopulations.  相似文献