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Semivariogram

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https://www.readbyqxmd.com/read/27747271/spatial-variation-of-arsenic-in-soil-irrigation-water-and-plant-parts-a-microlevel-study
#1
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
#2
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
https://www.readbyqxmd.com/read/27510986/assessment-of-the-spatial-variability-in-tall-wheatgrass-forage-using-landsat-8-satellite-imagery-to-delineate-potential-management-zones
#3
Pablo Cicore, João Serrano, Shakib Shahidian, Adelia Sousa, José Luis Costa, José Rafael Marques da Silva
Little information is available on the degree of within-field variability of potential production of Tall wheatgrass (Thinopyrum ponticum) forage under unirrigated conditions. The aim of this study was to characterize the spatial variability of the accumulated biomass (AB) without nutritional limitations through vegetation indexes, and then use this information to determine potential management zones. A 27-×-27-m grid cell size was chosen and 84 biomass sampling areas (BSA), each 2 m(2) in size, were georeferenced...
December 0: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/27506022/-distribution-characteristics-and-influencing-factors-of-nitrate-pollution-in-shallow-groundwater-of-liujiang-basin
#4
He Wang, Hong-biao Gu, Bao-ming Chi, Hai-jun Li, Hai-ning Jiang
Taking the nitrate in shallow groundwater of Liujiang basin as the research object, a total of 215 groups of shallow groundwater samples were collected during the wet period in July 2014 and the drought period in April 2015 on the basis of groundwater pollution investigation. The characteristics of spatial and temporal variability and the account of nitrate pollution were analyzed based on the model of semivariogram, the geostatistics of ArcGIS and factor analysis, respectively. The results showed that the study region in the southeast was the main nitrate-polluted area, with concentrations of up to 30-120 mg · L⁻¹, in both wet and drought periods, while the nitrate-contaminated area in drought period was about 1...
May 15, 2016: Huan Jing Ke Xue= Huanjing Kexue
https://www.readbyqxmd.com/read/27471983/recent-climatic-events-controlling-the-hydrological-and-the-aquifer-dynamics-at-arid-areas-the-case-of-huasco-river-watershed-northern-chile
#5
I Salas, C Herrera, J A Luque, J Delgado, J Urrutia, T Jordan
The investigation assesses the influence of recent climatic events in the water resources and the aquifer dynamics in the Huasco watershed by means of the analysis of precipitation, streamflow and piezometric levels during the last 50years. These hydrological and hydrogeological parameters were evaluated by an exploratory geostatistical analysis (semivariogram) and a spectral analysis (periodogram). Specifically, the hydrological and hydrogeological data analyses are organized according to three sub-basins, the Del Carmen River (Section I), the El Tránsito River (Section II), and the Huasco River (Section III)...
November 15, 2016: Science of the Total Environment
https://www.readbyqxmd.com/read/27429872/erratum-to-lessening-the-adverse-effect-of-the-semivariogram-model-selection-on-an-interpolative-survey-using-kriging-technique
#6
Zakari Arétouyap, Philippe Njandjock Nouck, Robert Nouayou, Franck Eithel Ghomsi Kemgang, Axel Dorian Piépi Toko, Jamal Asfahani
[This corrects the article DOI: 10.1186/s40064-016-2142-4.].
2016: SpringerPlus
https://www.readbyqxmd.com/read/27359000/assessment-of-groundwater-quality-using-dea-and-ahp-a-case-study-in-the-sereflikochisar-region-in-turkey
#7
Murat Kavurmaci, A Korkut Üstün
This study investigated the spatial distribution of groundwater quality in Sereflikochisar Basin, in the Central Anatolian region of Turkey using different hydrochemical, statistical, and geostatistical methods. A total of 51 groundwater samples were collected from the observation wells in the study area to evaluate the characteristics of the groundwater quality. As a relatively simple and practical method, a groundwater quality index (GWQI) was developed to evaluate the overall groundwater quality. In this process, complex decision-making techniques such as analytic hierarchy process (AHP) and data envelopment analysis (DEA) were used...
April 2016: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/27190748/lessening-the-adverse-effect-of-the-semivariogram-model-selection-on-an-interpolative-survey-using-kriging-technique
#8
Zakari Arétouyap, Philippe Njandjock Nouck, Robert Nouayou, Franck Eithel Ghomsi Kemgang, Axel Dorian Piépi Toko, Jamal Asfahani
OBJECTIVE: Many parameters in environmental, scientific and human sciences investigations need to be interpolated. Geostatistics, with its structural analysis step, is widely used for this purpose. This precious step that evaluates data correlation and dependency is performed thanks to semivariogram. However, an incorrect choice of a semivariogram model can skew all the prediction results. The main objectives of this paper are (1) to simply illustrate the influence of the choice of an inappropriate semivariogram model and (2) to show how a best-fitted model can be selected...
2016: SpringerPlus
https://www.readbyqxmd.com/read/27110991/geospatial-variability-of-soil-co2-c-exchange-in-the-main-terrestrial-ecosystems-of-keller-peninsula-maritime-antarctica
#9
A Thomazini, M R Francelino, A B Pereira, A L Schünemann, E S Mendonça, P H A Almeida, C E G R Schaefer
Soils and vegetation play an important role in the carbon exchange in Maritime Antarctica but little is known on the spatial variability of carbon processes in Antarctic terrestrial environments. The objective of the current study was to investigate (i) the soil development and (ii) spatial variability of ecosystem respiration (ER), net ecosystem CO2 exchange (NEE), gross primary production (GPP), soil temperature (ST) and soil moisture (SM) under four distinct vegetation types and a bare soil in Keller Peninsula, King George Island, Maritime Antarctica, as follows: site 1: moss-turf community; site 2: moss-carpet community; site 3: phanerogamic antarctic community; site 4: moss-carpet community (predominantly colonized by Sanionia uncinata); site 5: bare soil...
August 15, 2016: Science of the Total Environment
https://www.readbyqxmd.com/read/27078967/-pollution-assessment-and-spatial-distribution-characteristics-of-heavy-metals-in-soils-of-coal-mining-area-in-longkou-city
#10
Shuo Liu, Quan-yuan Wu, Xue-jiang Cao, Ji-ning Wang, Long-long Zhang, Dong-quan Cai, Li-yuan Zhou, Na Liu
The present paper takes the coal mining area of Longkou City as the research area. Thirty-six topsoil (0-20 cm) samples were collected and the contents of 5 kinds of heavy metals were determined, including Cd, As, Ni, Ph, Cr. Geo-statistics analysis was used to analyze the spatial distribution of heavy metals. Principal component analysis (PCA) was used to explore the pollution sources of heavy metals and the degree of heavy metals pollution was evaluated by weighted average comprehensive pollution evaluation method...
January 15, 2016: Huan Jing Ke Xue= Huanjing Kexue
https://www.readbyqxmd.com/read/27069713/spatial-variability-and-distribution-of-the-metals-in-surface-runoff-in-a-nonferrous-metal-mine
#11
Bozhi Ren, Yangbo Chen, Guocheng Zhu, Zhenghua Wang, Xie Zheng
The spatial variation and distribution features of the metals tested in the surface runoff in Xikuangshan Bao Daxing miming area were analyzed by combining statistical methods with a geographic information system (GIS). The results showed that the maximum concentrations of those five kinds of the metals (Sb, Zn, Cu, Pb, and Cd) in the surface runoff of the antimony mining area were lower than the standard value except the concentration of metal Ni. Their concentrations were 497.1, 2.0, 1.8, 22.2, and 22.1 times larger than the standard value, respectively...
2016: Journal of Analytical Methods in Chemistry
https://www.readbyqxmd.com/read/27067017/uncertainty-assessment-of-pm2-5-contamination-mapping-using-spatiotemporal-sequential-indicator-simulations-and-multi-temporal-monitoring-data
#12
Yong Yang, George Christakos, Wei Huang, Chengda Lin, Peihong Fu, Yang Mei
Because of the rapid economic growth in China, many regions are subjected to severe particulate matter pollution. Thus, improving the methods of determining the spatiotemporal distribution and uncertainty of air pollution can provide considerable benefits when developing risk assessments and environmental policies. The uncertainty assessment methods currently in use include the sequential indicator simulation (SIS) and indicator kriging techniques. However, these methods cannot be employed to assess multi-temporal data...
2016: Scientific Reports
https://www.readbyqxmd.com/read/27034240/assessment-of-groundwater-quality-using-dea-and-ahp-a-case-study-in-the-sereflikochisar-region-in-turkey
#13
Murat Kavurmaci, A Korkut Üstün
This study investigated the spatial distribution of groundwater quality in Sereflikochisar Basin, in the Central Anatolian region of Turkey using different hydrochemical, statistical, and geostatistical methods. A total of 51 groundwater samples were collected from the observation wells in the study area to evaluate the characteristics of the groundwater quality. As a relatively simple and practical method, a groundwater quality index (GWQI) was developed to evaluate the overall groundwater quality. In this process, complex decision-making techniques such as analytic hierarchy process (AHP) and data envelopment analysis (DEA) were used...
April 2016: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/26935208/small-scale-spatio-temporal-distribution-of-bactrocera-minax-enderlein-diptera-tephritidae-using-probability-kriging
#14
S Q Wang, H Y Zhang, Z L Li
Understanding spatio-temporal distribution of pest in orchards can provide important information that could be used to design monitoring schemes and establish better means for pest control. In this study, the spatial and temporal distribution of Bactrocera minax (Enderlein) (Diptera: Tephritidae) was assessed, and activity trends were evaluated by using probability kriging. Adults of B. minax were captured in two successive occurrences in a small-scale citrus orchard by using food bait traps, which were placed both inside and outside the orchard...
March 3, 2016: Neotropical Entomology
https://www.readbyqxmd.com/read/26687089/quantifying-specific-capacity-and-salinity-variability-in-amman-zarqa-basin-central-jordan-using-empirical-statistical-and-geostatistical-techniques
#15
F Shaqour, R Taany, O Rimawi, G Saffarini
Modeling groundwater properties is an important tool by means of which water resources management can judge whether these properties are within the safe limits or not. This is usually done regularly and in the aftermath of crises that are expected to reflect negatively on groundwater properties, as occurred in Jordan due to crises in neighboring countries. In this study, specific capacity and salinity of groundwater of B2/A7 aquifer in Amman Zarqa Basin were evaluated to figure out the effect of population increase in this basin as a result of refugee flux from neighboring countries to this heavily populated basin after Gulf crises 1990 and 2003...
January 2016: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/26604370/spatial-variability-of-theaflavins-and-thearubigins-fractions-and-their-impact-on-black-tea-quality
#16
Lakshi Prasad Bhuyan, Paban Borah, Santanu Sabhapondit, Ramen Gogoi, Pradip Bhattacharyya
The spatial distribution of theaflavin and thearubigin fractions and their impact on black tea quality were investigated using multivariate and geostatistics techniques. Black tea samples were collected from tea gardens of six geographical regions of Assam and West Bengal, India. Total theaflavin (TF) and its four fractions of upper Assam, south bank and North Bank teas were higher than the other regions. Simple theaflavin showed highest significant correlation with tasters' quality. Low molecular weight thearubigins of south bank and North Bank were significantly higher than other regions...
December 2015: Journal of Food Science and Technology
https://www.readbyqxmd.com/read/26269104/uncertainty-assessment-of-heavy-metal-soil-contamination-mapping-using-spatiotemporal-sequential-indicator-simulation-with-multi-temporal-sampling-points
#17
Yong Yang, George Christakos
Mapping the space-time distribution of heavy metals in soils plays a key role in contaminated site classification under conditions of in situ uncertainty, whereas uncertainty assessment is based on the quantification of the specific uncertainties in terms of exceedance probabilities. Geostatistical space-time kriging (STK) is increasingly used to estimate pollutant concentrations in soils. Sequential indicator simulation (SIS) technique is popular in uncertainty assessment of heavy metal contamination of soils...
September 2015: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/26247056/soil-parameter-mapping-and-ad-hoc-power-analysis-to-increase-blocking-efficiency-prior-to-establishing-a-long-term-field-experiment
#18
Doug Collins, Chris Benedict, Andy Bary, Craig Cogger
The spatial heterogeneity of soil and weed populations poses a challenge to researchers. Unlike aboveground variability, below-ground variability is more difficult to discern without a strategic soil sampling pattern. While blocking is commonly used to control environmental variation, this strategy is rarely informed by data about current soil conditions. Fifty georeferenced sites were located in a 0.65 ha area prior to establishing a long-term field experiment. Soil organic matter (OM) and weed seed bank populations were analyzed at each site and the spatial structure was modeled with semivariograms and interpolated with kriging to map the surface...
2015: TheScientificWorldJournal
https://www.readbyqxmd.com/read/26174957/geostatistics-and-geographic-information-systems-to-study-the-spatial-distribution-of-grapholita-molesta-busck-lepidoptera-tortricidae-in-peach-fields
#19
F Duarte, M V Calvo, A Borges, I B Scatoni
The oriental fruit moth, Grapholita molesta (Busck), is the most serious pest in peach, and several insecticide applications are required to reduce crop damage to acceptable levels. Geostatistics and Geographic Information Systems (GIS) are employed to measure the range of spatial correlation of G. molesta in order to define the optimum sampling distance for performing spatial analysis and to determine the current distribution of the pest in peach orchards of southern Uruguay. From 2007 to 2010, 135 pheromone traps per season were installed and georeferenced in peach orchards distributed over 50,000 ha...
August 2015: Neotropical Entomology
https://www.readbyqxmd.com/read/26165991/county-scale-temporal-spatial-distribution-and-variability-tendency-of-heavy-metals-in-arable-soils-influenced-by-policy-adjustment-during-the-last-decade-a-case-study-of-changxing-china
#20
Peng Li, Yuyou Zhi, Jiachun Shi, Lingzao Zeng, Laosheng Wu
The widespread "pertinacious illness" for environmental management soil contamination by toxic metals has inevitably led to announcement of gradual adjustment for the local government to curb the notorious pollution. An extensive survey was conducted in Changxing County, Zhejiang Province, to investigate the contents of cadmium (Cd), arsenic (As), lead (Pb), and copper (Cu) and characterize the spatial-temporal change pattern to elucidate the current state and performance of policy adjustment. Geostatistic methods were applied in the mapping and characterizing processes to assess the concentrations of heavy metals at unsampled sites...
November 2015: Environmental Science and Pollution Research International
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