Object-based image analysis supported by data mining to discriminate large areas of soybean     

Carlos Antonio da Silva Junior  Marcos Rafael Nanni  José Francisco de Oliveira-Júnior  Everson Cezar  Paulo Eduardo Teodoro  Rafael Coll Delgado 《International Journal of Digital Earth》2019,12(3):270-292

This research aimed to analyze the possibility to estimate and automatically map large areas of soybean cultivation through the use of MODIS (Moderate-Resolution Imaging Spectroradiometer) images. Two major techniques were used: GEOgraphic-Object-Based Image Analysis (GEOBIA) and Data Mining (DM). In order to obtain the images, the segmentation algorithm implemented by Definiens Developer was used. A decision tree (DT) was created from a training set previously prepared. Time-series of images from the MODIS sensor aboard the Terra satellite were acquired in order to represent the wide variation of the vegetation pattern along the soybean crop cycle. The time-series data were used only for the CEI index. Furthermore, to compare the results obtained from GEOBIA, the slicing technique was used at the CEI level. After the training, the DT was applied to the vegetation indices generating the thematic map of the spatial distribution of soybean. In accordance with the error matrix and kappa parameter analysis, tests for statistical significance were created. Results indicate that the classification achieved by Kappa coefficients is 0.76. In short, the obtained results proved that combining vegetation indices and time-series data using GEOBIA return promising results for mapping soybean plantation on a regional scale.  相似文献   

Using Mahalanobis Distance to Detect and Remove Outliers in Experimental Covariograms     

Drumond  David Alvarenga  Rolo  Roberto Mentzingen  Costa  João Felipe Coimbra Leite 《Natural Resources Research》2019,28(1):145-152

Experimental variograms are crucial for most geostatistical studies. In kriging, for example, the variography has a direct influence on the interpolation weights. Despite the great importance of variogram estimators in predicting geostatistical features, they are commonly influenced by outliers in the dataset. The effect of some randomly spatially distributed outliers can mask the pattern of the experimental variogram and produce a destructuration effect, implying that the true data spatial continuity cannot be reproduced. In this paper, an algorithm to detect and remove the effect of outliers in experimental variograms using the Mahalanobis distance is proposed. An example of the algorithm’s application is presented, showing that the developed technique is able to satisfactorily detect and remove outliers from a variogram.

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Nursery use patterns of commercially important marine fish species in estuarine systems along the Portuguese coast     

R.P. Vasconcelos  P. Reis-Santos  A. Maia  V. Fonseca  S. França  N. Wouters  M.J. Costa  H.N. Cabral 《Estuarine, Coastal and Shelf Science》2010

Analysing the estuarine use patterns of juveniles of marine migrant fish species is vital for identifying important sites for juveniles as well as the basic environmental features that characterize these sites for different species. This is a key aspect towards understanding nursery function. Various estuarine systems along the Portuguese coast (Minho, Douro, Ria de Aveiro, Mondego, Tejo, Sado, Mira, Ria Formosa and Guadiana) were sampled during Spring and Summer 2005 and 2006. Juveniles of commercially important marine fish species Solea solea, Solea senegalensis, Platichthys flesus, Diplodus vulgaris and Dicentrarchus labrax, predominantly 0-group individuals, were amongst the most abundant species and had distinct patterns of estuarine use as well as conspicuous associations with several environmental features. Juvenile occurrence and density varied amongst estuaries and sites within them, and differed with species. Sites with consistently high juvenile densities were identified as important juvenile sites (i.e. putative nursery grounds). Through generalized linear models (GLM), intra-estuarine variation in occurrence and density of each of the individual species was largely explained by environmental variables (temperature; salinity; depth; percentage of mud in the sediment; presence of seagrass; importance of intertidal areas; relative distance to estuary mouth; macrozoobenthos densities; and latitude). Decisive environmental factors defining important sites for juveniles varied depending on the system as a result of different environmental gradients, though there were common dominant features for each species regardless of the estuary considered. Analysed environmental variables in the GLM also accounted for inter-estuarine variation in species' occurrence and density. In several estuaries, the identified important juvenile sites were used by many of these species simultaneously and may be of increased value to both management and conservation. Overall, the variability in site features amongst estuaries highlighted the tolerance of these species to different available environmental conditions and provided fundamental information for future spatially explicit modelling of their distribution. This should ultimately enable the prediction of species response to habitat alterations.  相似文献   

Fish assemblage structure on sandy beaches with different anthropogenic influences and proximity of spawning grounds          下载免费PDF全文

Hamilton H Pereira  Leonardo M Neves  Marcus R da Costa  Francisco G Araújo 《Marine Ecology》2015,36(1):16-27

Fish assemblages in an insular (preserved) and a continental (disturbed) sandy beach were compared to assess any changes that could be attributed to anthropogenic influences and/or the proximity of the fish spawning grounds. We expected that the closer geographical position to the spawning grounds and the small amount of anthropogenic disturbance on the insular beach would be likely to provide more suitable conditions for early fish development compared with the continental beach. A total of 192 samples (96 in each beach) were taken, yielding 68 fish species, mostly young‐of‐the‐year. Fish assemblage structure differed significantly between the two beaches. Moreover, the insular beach had higher number of species, number of individuals and biomass compared with the continental beach. The commercially important Clupeiformes Harengula clupeola, Anchoa tricolor and Anchoa januaria, Perciformes Micropogonias furnieri and Mugiliformes Mugil liza were typical species on the insular beach, partitioning the seasonal use of the beach. On the other hand, a few abundant non‐commercial species, mainly the Atheriniformes Atherinella brasiliensis and the Perciformes Eucinostomus argenteus and Diapterus rhombeus, occurred all year round at the continental beach. The high fish richness and abundance and the more conspicuous species turnover across seasons on the insular beach are probable indications of more complex and dynamic organization of the communities favored by better geographical position and less anthropogenic disturbance in the area.  相似文献   

Can the pattern of juvenile recruitment and population structure of the speckled swimming crab Arenaeus cribrarius (Decapoda: Brachyura) be determined by geographical variations?          下载免费PDF全文

Luciana Segura de Andrade  Israel Fernandes Frameschi  Antônio Leão Castilho  Rogério Caetano da Costa  Adilson Fransozo 《Marine Ecology》2015,36(4):950-958

This study evaluated the effect of environmental stimuli and selective pressures in different geographical areas along a latitudinal gradient, on the juvenile recruitment, population structure, and sex ratio of the speckled swimming crab Arenaeus cribrarius. Samples were collected monthly during 1 year in three locations along the Brazilian coast: Macaé, state of Rio de Janeiro (MAC, 22°47′ S, 41°45′ W); Ubatuba, São Paulo (UBA, 23°27′ S, 44°58′ W); and São Francisco do Sul, Santa Catarina (SFS, 26°08′ S, 48°34′ W). The specimens of A. cribrarius were identified, counted, sexed, and measured for maximum carapace width (CW). The largest juvenile found was in UBA (47.7 ± 1.36 mm); and the largest adult females and males in MAC (74.26 ± 0.93 and 77.04 ± 0.79 mm, respectively). Recruitment in MAC was continuous, whereas in UBA and SFS, recruitment showed seasonal characteristics. The sex ratio was skewed toward females only in UBA; in MAC and SFS, males and females were present in equal proportions. These results indicate that geographical variations can cause differences in the recruitment and population structure of A. cribrarius. These regional differences call attention to the necessity for improved management plans and control of shrimp fishing, which can affect population patterns such as juvenile recruitment, population structure and life history of the target species and species that are caught in bycatch from shrimping, such as the swimming crab A. cribrarius.  相似文献   

Analyzing the spatial interactions between rainfall levels and flooding prediction in São Paulo     

Wagner da Silva Billa  Leonardo Bacelar Lima Santos  Rogério Galante Negri 《Transactions in GIS》2023,27(8):2159-2174

Rainfall is one of the primary triggers for many geological and hydrological natural disasters. While the geological events are related to mass movements in land collapse due to waterlogging, the hydrological ones are usually assigned to runoff or flooding. Studies in the literature propose predicting mass movement events as a function of accumulated rainfall levels recorded at distinct periods. According to these approaches, a two-dimensional rainfall levels feature space is segmented into the occurrence and non-occurrence decision regions by an empirical critical curve (CC). Although this scheme may easily be extended to other purposes and applications, studies in the literature need to discuss its use for flooding prediction. In light of this motivation, the present study is unfolded in (1) verifying that defining CCs in the rainfall levels feature space is a practical approach for flooding prediction and (2) analyzing how geospatial components interact with rainfall levels and flooding prediction. A database containing the rainfall levels recorded for flooding and non-flooding events in São Paulo city, Brazil, regarding the period 2015–2016, was considered in this study. The results indicate good accuracy for flooding prediction using only partial rain, which can be improved by adding physical characteristics of the flooding locations, demonstrating a direct correlation with spatial interactions, and rainfall levels.  相似文献   

New Reference Materials,Analytical Procedures and Data Reduction Strategies for Sr Isotope Measurements in Geological Materials by LA-MC-ICP-MS     

Jacob Mulder  Graham Hagen-Peter  Teresa Ubide  Rasmus Andreasen  Ellen Kooijman  Melanie Kielman-Schmitt  Yue-Xing Feng  Bence Paul  Andreas Karlsson  Christian Tegner  Charles Lesher  Fidel Costa 《Geostandards and Geoanalytical Research》2023,47(2):311-336

Laser ablation multi-collector mass spectrometry (LA-MC-ICP-MS) has emerged as the technique of choice for in situ measurements of Sr isotopes in geological minerals. However, the method poses analytical challenges and there is no widely adopted standardised approach to collecting these data or correcting the numerous potential isobaric inferences. Here, we outline practical analytical procedures and data reduction strategies to help establish a consistent framework for collecting and correcting Sr isotope measurements in geological materials by LA-MC-ICP-MS. We characterise a new set of plagioclase reference materials, which are available for distribution to the community, and present a new data reduction scheme for the Iolite software package to correct isobaric interferences for different materials and analytical conditions. Our tests show that a combination of Kr-baseline subtraction, Rb-peak-stripping using βRb derived from a bracketing glass reference material, and a CaCa or CaAr correction for plagioclase and CaCa or CaAr + REE²⁺ correction for rock glasses, yields the most accurate and precise ⁸⁷Sr/⁸⁶Sr measurements for these materials. Using the analytical and correction procedures outlined herein, spot analyses using a beam diameter of 100 μm or rastering with a 50–65 μm diameter beam can readily achieve < 100 ppm 2SE repeatability ("internal") precision for ⁸⁷Sr/⁸⁶Sr measurements for materials with < 1000 μg g^-1 Sr.  相似文献   

Vertical deformation partitioning across a collapsing large and hot orogen     

F. A. Temporim  Ricardo Ivan Ferreirae da Trindade  Marcos Egydio-Silva  Tiago Valim Angelo  Eric Tohver  Caroline Cibele Soares  Lucas Pequeno Gouvêa  Julio Cesar Mendes  Silvia Regina Medeiros  Antônio Carlos Pedrosa-Soares  Gabriel Gomes Silva 《地学学报》2023,35(1):23-31

Featuring 3 000-km-long large and hot orogen, the Mantiqueira Province provides a rare opportunity to study the process of gravitational collapse at mid to deep crustal levels. Distinct but contemporary (~500 Ma) post-collisional intrusions show structures and anisotropy of magnetic susceptibility (AMS) fabrics related to their emplacements, recording different flow patterns. In southern deep-seated intrusions, ellipsoidal-shaped roots with gabbroic-to-hybrid cores surrounded by granitic rocks show concentric patterns of AMS fabrics that cut across the NE-trending regional foliation. In contrast, northern intrusions, exposed as the upper sections of batholith-size bodies of coarse-grained granite emplaced at the shallow to mid-crust, show general NS-trending magnetic fabrics roughly parallel to strike of the orogen and the regional foliation of host rocks. These contrasting magnetic patterns from shallow to deeper crust suggest vertical magma migration from the overthickened orogenic core to be emplaced across its thinner stretched flanks during the gravitational collapse of the orogenic edifice.  相似文献   

Paleoenvironmental dynamics in central-eastern Brazil during the last 23 000 years: tropical peatland record in the Cerrado biome     

Camila Rodrigues Costa  Cynthia Fernandes Pinto da Luz  Ingrid Horák-Terra  Plínio Barbosa de Camargo  Uidemar Morais Barral  Carlos Victor Mendonça-Filho  Thamyres Sabrina Gonçalves  Alexandre Christófaro Silva 《第四纪科学杂志》2023,38(1):61-75

The Cerrado biome is the second largest in Brazil, but the evolution of the Cerrado during the late Quaternary is not yet fully known. This study identifies paleoenvironmental changes during the last 23 000 years, based on a tropical mountain peatland record, in the Serra do Espinhaço Meridional in central-eastern Brazil. A multi-proxy approach was used that involved palynological analysis, stable isotopes (δ¹³C, δ¹⁵N), geochemistry, radiocarbon dating and multivariate statistics derived from a peatland core from Rio Preto (Minas Gerais state). The study reveals a very humid and cold climate during the late Pleistocene, with an increase in temperature and decrease in humidity at the Pleistocene–Holocene transition. During this period there was strong instability in the landscape (episodes of erosion). At the beginning of the Holocene there was a reduction in humidity with greater landscape stability. The current sub-humid climatic conditions seem to have been established in the mid-/late Holocene, with periods of landscape instability. Our findings agree with other Cerrado records that contradict previously established hypotheses, such as the Amazonian Refuge and the Pleistocene Arc.  相似文献   

Hydrogeological origin of the CO2-rich mineral water of Vilajuïga in the Eastern Pyrenees (NE Catalonia,Spain)     

Mas-Pla  Josep  Brusi  David  Roqué  Carles  Soler  David  Menció  Anna  Costa  Josep M  Zamorano  Manuel  Meredith  Warren 《Hydrogeology Journal》2023,31(3):661-684

The mineral water of Vilajuïga village in Alt Empordà (NE Catalonia, Spain) owes its uniqueness to an emanation of geogenic CO₂ that modifies groundwater hydrochemistry to produce a differentiated HCO₃–Na- and CO₂-rich groundwater among the usual Ca–HCO₃ type found in this region. A hydrogeological conceptual model attributes its occurrence to the intersection of two faults: La Valleta and Garriguella-Roses. The former provides a thrust of metamorphic over igneous rocks, formed during the Paleozoic, over a layer of ampelitic shale that, from a hydrogeological perspective, acts as a confining layer. The Garriguella-Roses normal fault, which originated during the Neogene, permits the degassing of geogenic CO₂ that is attributed to volcanic activity occurring in the Neogene. Groundwater mixing from the metamorphic and igneous rock units plus the local occurrence of CO₂ creates a HCO₃–Na water that still holds free-CO₂ in solution. Interaction with the gas phase is restricted at the intersection of the two faults. Radiocarbon dating, after correcting for geogenic dead carbon, estimates an age of 8,000 years BP. The low tritium content (0.7 TU) indicates that Vilajuïga water is a mix of “older” groundwater recharged in the metamorphic rocks of the Albera range and “younger” groundwater from the igneous rocks of the Rodes range, over a recharge area of 45 km² and a maximum elevation of 600 m. Given its origin as rare groundwater in the southern slope of the Eastern Pyrenees, purposeful monitoring is necessary to evaluate the groundwater vulnerability and anticipate impacts from nearby wells and climate-change effects.

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