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Semivariogram

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https://www.readbyqxmd.com/read/29758908/spatial-relationships-among-cereal-yields-and-selected-soil-physical-and-chemical-properties
#1
Jerzy Lipiec, Bogusław Usowicz
Sandy soils occupy large area in Poland (about 50%) and in the world. This study aimed at determining spatial relationships of cereal yields and the selected soil physical and chemical properties in three study years (2001-2003) on low productive sandy Podzol soil (Podlasie, Poland). The yields and soil properties in plough and subsoil layers were determined at 72-150 points. The test crops were: wheat, wheat and barley mixture and oats. To explore the spatial relationship between cereal yields and each soil property spatial statistics was used...
August 15, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/29745136/-spatial-heterogeneity-of-soil-salinization-and-its-influencing-factors-in-the-typical-region-of-the-mu-us-desert-loess-plateau-transitional-zone-northwest-china
#2
Xuan Zhao, Qi Li Hao, Ying Ying Sun
Studies on the spatial heterogeneity of saline soil in the Mu Us Desert-Loess Plateau transition zone are meaningful for understanding the mechanisms of land desertification. Taking the Mu Us Desert-Loess Plateau transition zone as the study subject, its spatial heterogeneity of pH, electrical conductivity (EC) and total salt content were analyzed by using on-site sampling followed with indoor analysis, classical statistical and geostatistical analysis. The results indicated that: 1) The average values of pH, EC and total salt content were 8...
June 18, 2017: Ying Yong Sheng Tai Xue Bao, the Journal of Applied Ecology
https://www.readbyqxmd.com/read/29692113/-spatial-evolution-of-land-use-intensity-and-landscape-pattern-response-of-the-typical-basins-in-guizhou-province-china
#3
Ya Xiang Liu, Yang Bing Li, Xing Song Yi, Xing Cheng
Based on the small scale characteristics of the basin, which is a kind of special landform influenced by the human activities obviously in Karst mountain area, the system grid method and the semivariogram model were used to analyze the 15 basins which belonged to three types in the territory of Guizhou Province to reveal the general pattern of spatial evolution of land use intensity and the mutual relationship with the landscape pattern change of the typical basins in the Karst mountainous area of Guizhou Province in 2005, 2010 and 2015...
November 2017: Ying Yong Sheng Tai Xue Bao, the Journal of Applied Ecology
https://www.readbyqxmd.com/read/29692079/-characteristics-of-temporal-spatial-differentiation-in-landscape-pattern-vulnerability-in-nansihu-lake-wetland-china
#4
Jia Xin Liang, Xin Ju Li
With remote sensing images from 1985, 2000 Lantsat 5 TM and 2015 Lantsat 8 OLI as data sources, we tried to select the suitable research scale and examine the temporal-spatial diffe-rentiation with such scale in the Nansihu Lake wetland by using landscape pattern vulnerability index constructed by sensitivity index and adaptability index, and combined with space statistics such as semivariogram and spatial autocorrelation. The results showed that 1 km × 1 km equidistant grid was the suitable research scale, which could eliminate the influence of spatial heterogeneity induced by random factors...
February 2018: Ying Yong Sheng Tai Xue Bao, the Journal of Applied Ecology
https://www.readbyqxmd.com/read/29589150/assessment-of-the-pollution-and-ecological-risk-of-lead-and-cadmium-in-soils
#5
Jerzy Wieczorek, Agnieszka Baran, Krzysztof Urbański, Ryszard Mazurek, Agnieszka Klimowicz-Pawlas
The aim of the study was to assess the content, distribution, soil binding capacity, and ecological risk of cadmium and lead in the soils of Malopolska (South Poland). The investigation of 320 soil samples from differently used land (grassland, arable land, forest, wasteland) revealed a very high variation in the metal content in the soils. The pollution of soils with cadmium and lead is moderate. Generally, a point source of lead and cadmium pollution was noted in the study area. The highest content of cadmium and lead was found in the northwestern part of the area-the industrial zones (mining and metallurgical activity)...
March 27, 2018: Environmental Geochemistry and Health
https://www.readbyqxmd.com/read/29572743/comparing-ordinary-kriging-and-inverse-distance-weighting-for-soil-as-pollution-in-beijing
#6
Pengwei Qiao, Mei Lei, Sucai Yang, Jun Yang, Guanghui Guo, Xiaoyong Zhou
Spatial interpolation method is the basis of soil heavy metal pollution assessment and remediation. The existing evaluation index for interpolation accuracy did not combine with actual situation. The selection of interpolation methods needs to be based on specific research purposes and research object characteristics. In this paper, As pollution in soils of Beijing was taken as an example. The prediction accuracy of ordinary kriging (OK) and inverse distance weighted (IDW) were evaluated based on the cross validation results and spatial distribution characteristics of influencing factors...
March 23, 2018: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/29427938/comparison-of-the-common-spatial-interpolation-methods-used-to-analyze-potentially-toxic-elements-surrounding-mining-regions
#7
Qian Ding, Yong Wang, Dafang Zhuang
The appropriate spatial interpolation methods must be selected to analyze the spatial distributions of Potentially Toxic Elements (PTEs), which is a precondition for evaluating PTE pollution. The accuracy and effect of different spatial interpolation methods, which include inverse distance weighting interpolation (IDW) (power = 1, 2, 3), radial basis function interpolation (RBF) (basis function: thin-plate spline (TPS), spline with tension (ST), completely regularized spline (CRS), multiquadric (MQ) and inverse multiquadric (IMQ)) and ordinary kriging interpolation (OK) (semivariogram model: spherical, exponential, gaussian and linear), were compared using 166 unevenly distributed soil PTE samples (As, Pb, Cu and Zn) in the Suxian District, Chenzhou City, Hunan Province as the study subject...
April 15, 2018: Journal of Environmental Management
https://www.readbyqxmd.com/read/29380716/spatiotemporal-heterogeneity-of-malnutrition-indicators-in-children-under-5-years-of-age-in-bangladesh-1999-2011
#8
Md Tanvir Hasan, Abdullah A Mamun, Gail M Williams, Ricardo J Soares Magalhães
OBJECTIVE: To examine changes in the spatial clustering of malnutrition in children under 5 years of age (under-5s) for the period 1999 to 2011 in Bangladesh. DESIGN: We used data from four nationally representative Demographic and Health Surveys (DHS) conducted in 1999-2000, 2004, 2007 and 2011 in Bangladesh involving a total of 24 211 under-5s located in 1661 primary sampling units (PSU; geographical unit of analysis) throughout Bangladesh. The prevalence of stunting (height/length-for-age Z-score <-2), underweight (weight-for-age Z-score <-2) and wasting (weight-for-height/length Z-score <-2) at each PSU site and for each survey year were estimated based on the WHO child growth standard...
April 2018: Public Health Nutrition
https://www.readbyqxmd.com/read/29241136/submillimeter-scale-heterogeneity-of-labile-phosphorus-in-sediments-characterized-by-diffusive-gradients-in-thin-films-and-spatial-analysis
#9
Yuting Meng, Shiming Ding, Mengdan Gong, Musong Chen, Yan Wang, Xianfang Fan, Lei Shi, Chaosheng Zhang
Sediments have a heterogeneous distribution of labile redox-sensitive elements due to a drastic downward transition from oxic to anoxic condition as a result of organic matter degradation. Characterization of the heterogeneous nature of sediments is vital for understanding of small-scale biogeochemical processes. However, there are limited reports on the related specialized methodology. In this study, the monthly distributions of labile phosphorus (P), a redox-sensitive limiting nutrient, were measured in the eutrophic Lake Taihu by Zr-oxide diffusive gradients in thin films (Zr-oxide DGT) on a two-dimensional (2D) submillimeter level...
March 2018: Chemosphere
https://www.readbyqxmd.com/read/29196730/spatiotemporal-modeling-and-prediction-of-soil-heavy-metals-based-on-spatiotemporal-cokriging
#10
Bei Zhang, Yong Yang
Soil heavy metals exhibit significant spatiotemporal variability and are strongly correlated with other soil heavy metals. Thus, other heavy metals can be used to improve the accuracy of predictions when performing spatiotemporal predictions of soil heavy metals within a given area. In this study, we propose the spatiotemporal cokriging (STCK) method to enable the use of historical sampling points and co-variables in the spatial prediction of soil heavy metals. Moreover, experimental spatiotemporal (ST) semivariogram and ST cross-semivariogram computational methods, a fitting strategy to the ST semivariogram and ST cross-semivariogram models based on the Bilonick model, and the STCK interpolation algorithm are introduced; these methods are based on spatiotemporal kriging (STK) and cokriging (CK)...
December 1, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28944409/characterizing-groundwater-quality-ranks-for-drinking-purposes-in-sylhet-district-bangladesh-using-entropy-method-spatial-autocorrelation-index-and-geostatistics
#11
Abu Reza Md Towfiqul Islam, Nasir Ahmed, Md Bodrud-Doza, Ronghao Chu
Drinking water is susceptible to the poor quality of contaminated water affecting the health of humans. Thus, it is an essential study to investigate factors affecting groundwater quality and its suitability for drinking uses. In this paper, the entropy theory, multivariate statistics, spatial autocorrelation index, and geostatistics are applied to characterize groundwater quality and its spatial variability in the Sylhet district of Bangladesh. A total of 91samples have been collected from wells (e.g., shallow, intermediate, and deep tube wells at 15-300-m depth) from the study area...
December 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28881956/geostatistical-characterization-of-cereal-leaf-beetle-coleoptera-chrysomelidae-distributions-in-wheat
#12
Francis P F Reay-Jones
A 3-yr study was conducted in wheat, Triticum aestivum L., in South Carolina to characterize the spatial distribution of Oulema melanopus (L.) adults, eggs, and larvae using semivariograms, which provides a measure of spatial dependence among sampling data. Moran's I coefficients for peak densities of each life stage indicated significant positive autocorrelation for seven (two for eggs, one for larvae, and four for adults) of the 16 datasets. Aggregation was detected in 13 of these 16 datasets when analyzed by semivariogram modeling, with spherical, Gaussian, and exponential models best fitting for eight, four, and one dataset, respectively, and with models for two datasets having only one parameter (nugget) significantly different from zero...
August 1, 2017: Environmental Entomology
https://www.readbyqxmd.com/read/28531962/how-geostatistics-can-help-you-find-lead-and-galvanized-water-service-lines-the-case-of-flint-mi
#13
Pierre Goovaerts
In the aftermath of Flint drinking water crisis, most US cities have been scrambling to locate all lead service lines (LSLs) in their water supply systems. This information, which is most often inaccurate or lacking, is critical to assess compliance with the Lead and Copper Rule and to plan the replacement of lead and galvanized service lines (GSLs) as currently under way in Flint. This paper presents the first geospatial approach to predict the likelihood that a home has a LSL or GSL based on neighboring field data (i...
December 1, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28428829/semivariogram-analysis-of-bone-images-implemented-on-fpga-architectures
#14
Mukul Shirvaikar, Yamuna Lagadapati, Xuanliang Dong
Osteoporotic fractures are a major concern for the healthcare of elderly and female populations. Early diagnosis of patients with a high risk of osteoporotic fractures can be enhanced by introducing second-order statistical analysis of bone image data using techniques such as variogram analysis. Such analysis is computationally intensive thereby creating an impediment for introduction into imaging machines found in common clinical settings. This paper investigates the fast implementation of the semivariogram algorithm, which has been proven to be effective in modeling bone strength, and should be of interest to readers in the areas of computer-aided diagnosis and quantitative image analysis...
March 2017: Journal of Real-Time Image Processing
https://www.readbyqxmd.com/read/28264424/kriging-with-unknown-variance-components-for-regional-ionospheric-reconstruction
#15
Ling Huang, Hongping Zhang, Peiliang Xu, Jianghui Geng, Cheng Wang, Jingnan Liu
Ionospheric delay effect is a critical issue that limits the accuracy of precise Global Navigation Satellite System (GNSS) positioning and navigation for single-frequency users, especially in mid- and low-latitude regions where variations in the ionosphere are larger. Kriging spatial interpolation techniques have been recently introduced to model the spatial correlation and variability of ionosphere, which intrinsically assume that the ionosphere field is stochastically stationary but does not take the random observational errors into account...
February 27, 2017: Sensors
https://www.readbyqxmd.com/read/28229257/potential-ecological-risk-assessment-and-predicting-zinc-accumulation-in-soils
#16
Agnieszka Baran, Jerzy Wieczorek, Ryszard Mazurek, Krzysztof Urbański, Agnieszka Klimkowicz-Pawlas
The aims of this study were to investigate zinc content in the studied soils; evaluate the efficiency of geostatistics in presenting spatial variability of zinc in the soils; assess bioavailable forms of zinc in the soils and to assess soil-zinc binding ability; and to estimate the potential ecological risk of zinc in soils. The study was conducted in southern Poland, in the Malopolska Province. This area is characterized by a great diversity of geological structures and types of land use and intensity of industrial development...
February 2018: Environmental Geochemistry and Health
https://www.readbyqxmd.com/read/28028098/spatial-distribution-and-coexisting-patterns-of-adults-and-nymphs-of-tibraca-limbativentris-hemiptera-pentatomidae-in-paddy-rice-fields
#17
Tavvs M Alves, Aline H N Maia, José A F Barrigossi
The rice stem stink bug, Tibraca limbativentris Stål (Hemiptera: Pentatomidae), is a primary insect pest of paddy rice in South America. Knowledge of its spatial distribution can support sampling plans needed for timely decisions about pest control. This study aimed to investigate the spatial distribution of adults and nymphs of T. limbativentris and determine the spatial coexistence of these stages of development. Fifteen paddy rice fields were scouted once each season to estimate insect densities. Scouting was performed on regular grids with sampling points separated by ∼50 m...
December 2016: Environmental Entomology
https://www.readbyqxmd.com/read/27920956/grassland-productivity-in-response-to-nutrient-additions-and-herbivory-is-scale-dependent
#18
Erica A H Smithwick, Douglas C Baldwin, Kusum J Naithani
Vegetation response to nutrient addition can vary across space, yet studies that explicitly incorporate spatial pattern into experimental approaches are rare. To explore whether there are unique spatial scales (grains) at which grass response to nutrients and herbivory is best expressed, we imposed a large (∼3.75 ha) experiment in a South African coastal grassland ecosystem. In two of six 60 × 60 m grassland plots, we imposed a scaled sampling design in which fertilizer was added in replicated sub-plots (1 × 1 m, 2 × 2 m, and 4 × 4 m)...
2016: PeerJ
https://www.readbyqxmd.com/read/27747271/spatial-variation-of-arsenic-in-soil-irrigation-water-and-plant-parts-a-microlevel-study
#19
M S Kabir, M A Salam, D N R Paul, M I Hossain, N M F Rahman, Abdullah Aziz, M A Latif
Arsenic pollution became a great problem in the recent past in different countries including Bangladesh. The microlevel studies were conducted to see the spatial variation of arsenic in soils and plant parts contaminated through ground water irrigation. The study was performed in shallow tube well command areas in Sadar Upazila (subdistrict), Faridpur, Bangladesh, where both soil and irrigation water arsenic are high. Semivariogram models were computed to determine the spatial dependency of soil, water, grain, straw, and husk arsenic (As)...
2016: TheScientificWorldJournal
https://www.readbyqxmd.com/read/27695761/kriging-models-predicting-atrazine-concentrations-in-surface-water-draining-agricultural-watersheds
#20
Paul L Mosquin, Jeremy Aldworth, Wenlin Chen
The performance of kriging methods in predicting maximum m-day (m = 1, 7, 14, or 30) rolling averages of atrazine concentrations in 42 site-years of Midwest Corn Belt watersheds under two systematic sampling designs (sampling every 7 or 14 d) was examined. Daily atrazine monitoring data obtained from the Atrazine Ecological Monitoring Program in the Corn Belt region (2009-2014) were used in the evaluation. Both ordinary and universal kriging methods were considered, with the covariate for universal kriging derived from the deterministic Pesticide Root Zone Model (PRZM)...
September 2016: Journal of Environmental Quality
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