Consulta: subjectFacets:"Calibration"
Registros recuperados: 60
Data/hora: 11/06/2024 00:28:12

Riesgo por inundación asociada a eventos de precipitación extraordinaria en la subcuenca del río La Antigua, Veracruz.
Provedor de dados: 32
Autores: Larios Tlali, Hugo.
El objetivo del presente estudio fue aplicar el modelo de simulación hidráulica HEC-RAS para delimitar las zonas con riesgo a inundación en la subcuenca del río La Antigua, Ver., utilizando la metodología del Centro Nacional de Prevención de Desastres (CENAPRED) que considera la vulnerabilidad y el peligro de un sistema ante la ocurrencia de un fenómeno extremo perturbador. El modelo HEC-RAS usa ecuaciones diferenciales determinísticas que simulan el comportamiento y la dinámica de los niveles de agua en secciones transversales del cauce; su aplicación bajo condiciones de flujo no permanente y régimen mixto, permitió definir las áreas de inundación alcanzadas durante una avenida extraordinaria. Para la simulación hidráulica se construyeron hidrogramas...
Palavras-chave: Simulación hidráulica; Inundación; Hidrograma; Fenómenos hidrometeorológicos extremos; Calibración; Validación; Riesgo por inundación; Hydraulic simulation; Flood hydrograph; Extreme weather phenomena; Calibration; Validation; Flood risk; Hidrociencias; Maestría.
Ano: 2014
URL: http://hdl.handle.net/10521/2375

Hydrological Modeling of Tributaries of Cantareira System, Southeast Brazil, with the Swat Model
Provedor de dados: 70
Autores: Pontes,Lucas M.; Viola,Marcelo R.; Silva,Marx L. Naves; Bispo,Diêgo F. A.; Curi,Nilton.
ABSTRACT The lack of hydrological data in Brazil is the main limitation for structuring hydrological models, which are able to assist water resources management. Therefore, studies are needed to evaluate the performance of models without on-site calibration. Within this context, the aim of this study was to calibrate the SWAT hydrological model for the Camanducaia River Basin and to evaluate the performance of this calibration in a contiguous drainage basin, one of the Jaguarí River. For the calibration and validation steps, the SWAT-CUP program was utilized. Uncertainty analysis and calculation of efficiency indexes were carried out through the SUFI-2 algorithm. The SWAT adjustment in the Camanducaia River Basin obtained adequate results, with a...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Calibration; Model transfer; Uncertainty analysis; Water security.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000601037

Hydrological simulation using SWAT model in headwater basin in Southeast Brazil
Provedor de dados: 70
Autores: Pereira,Donizete dos R.; Martinez,Mauro A.; Almeida,André Q. de; Pruski,Fernando F.; Silva,Demetrius D. da; Zonta,João H.
Hydrological models are important tools that have been used in water resource planning and management. Thus, the aim of this work was to calibrate and validate in a daily time scale, the SWAT model (Soil and Water Assessment Tool) to the watershed of the Galo creek , located in Espírito Santo State. To conduct the study we used georeferenced maps of relief, soil type and use, in addition to historical daily time series of basin climate and flow. In modeling were used time series corresponding to the periods Jan 1, 1995 to Dec 31, 2000 and Jan 1, 2001 to Dec 20, 2003 for calibration and validation, respectively. Model performance evaluation was done using the Nash-Sutcliffe coefficient (E NS) and the percentage of bias (P BIAS). SWAT evaluation was also...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hydrological modeling; SWAT; Calibration; Validation.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162014000400018

Sensibility analysis of the pearl model for pesticide leaching in the State of Mato Grosso do Sul, Brazil
Provedor de dados: 70
Autores: Scorza Júnior,Rômulo P.; Silva,João P. da.
For an accurate use of pesticide leaching models it is necessary to assess the sensitivity of input parameters. The aim of this work was to carry out sensitivity analysis of the pesticide leaching model PEARL for contrasting soil types of Dourados river watershed in the state of Mato Grosso do Sul, Brazil. Sensitivity analysis was done by carrying out many simulations with different input parameters and calculating their influence on the output values. The approach used was called one-at-a-time sensitivity analysis, which consists in varying independently input parameters one at a time and keeping all others constant with the standard scenario. Sensitivity analysis was automated using SESAN tool that was linked to the PEARL model. Results have shown that...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Calibration; Pesticide leaching model; Inverse modeling.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162011000500014

ABSOLUTE CALIBRATION OF THE ERS-2 SCATTEROMETER IN GYRO-LESS MODE USING TRANSPONDERS
Provedor de dados: 72
Autores: Manise,Nicolas; Neyt,Xavier; Acheroy,Marc.
The scatterometer on-board ERS-2, earth-observation satellite developed by the European Space Agency, is an active real aperture radar instrument designed to measure the backscatter coefficient 0 from the earth. Its main utility is to measure physical parameters such as wind speeds and directions over the sea surface. Due to malfunctions of the on-board gyroscopes and even though a new attitude and orbit control system is used, the yaw-orientation of the spacecraft still exhibits random variations from the nominal attitude. This unpredictable attitude requires re-developing the calibration chain of the scatterometer instrument. Distributed targets, such as the rain forest, are used to perform a relative calibration while transponders situated at known...
Tipo: Journal article
Palavras-chave: Scatterometer; Calibration; Transponder.
Ano: 2004
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382004000300011

Modelación del arroz en Latinoamérica: estado del arte y base de datos para parametrización.
Provedor de dados: 14
Autores: REBOLLEDO-CID, M. C.; RAMÍREZ-VILLEGAS, J.; GRATEROL-MATUTE, E.; HERNÁNDEZ-VARELA, C. A.; RODRÍGUEZ-ESPINOZA, J.; PETRO-PÁEZ, E. H.; PINZÓN, S.; HEINEMANN, A. B.; RODRÍGUEZ-BAIDE, J. M.; VAN DEN BERG, M.
El arroz en Latinoamérica y el Caribe (LAC) es un cultivo de gran importancia social y económica. El consumo de arroz en LAC ha aumentado significativamente durante los últimos años, registrando un promedio actual de 30 kg persona-1 año-1. La particularidad del arroz producido en LAC está en una alta calidad de grano y una producción que se realiza en su mayoría bajo sistemas mecanizados con siembra directa. En LAC, el arroz es producido bajo riego y secano dentro de diferentes eco-regiones (templado, tropical húmedo, tropical seco). La seguridad alimentaria y el cambio climático constituyen un reto para la producción de arroz en LAC, elevando la necesidad de aumentar, pero a su vez estabilizar los rendimientos y la calidad del grano. La modelación de...
Tipo: Livro técnico (INFOTECA-E)
Palavras-chave: América Latina; Arroz; Oryza sativa; Modelo de simulação; Rice; Simulation models; Climate change; Calibration.
Ano: 2018
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/1090979

Calibração do medidor de clorofila Minolta SPAD-502 para uso na cultura do milho.
Provedor de dados: 14
Autores: ZOTARELLI, L.; CARDOSO, E. G.; PICCININ, J. L.; URQUIAGA, S.; BODDEY, R. M.; TORRES, E.; ALVES, B. J. R.
bitstream/CNPAB-2010/28067/1/cot055.pdf
Tipo: Comunicado Técnico (INFOTECA-E)
Palavras-chave: Calibração; Maize.; Clorofila; Fotossíntese; Medição; Milho; Pigmento.; Calibration; Pigments.; Photosynthesis.
Ano: 2002
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/624249

Influência de diferentes adubações sobre a produção de milho no Nordeste e obtenção de informações para calibração de análise de solo.
Provedor de dados: 14
Autores: FARIA, C. M. B. de; MELO, J. N.; SÁ, V. A. de L.; TIMÓTEO SOBRINHO, A.; SANTOS, M. A. C. dos.
Foram analisados 57 experimentos instalados em vários locais do Nordeste durante os anos de 1974 a 1979 com os seguintes objetivos: a) avaliar a influência da aplicação de fertilizantes no rendimento da cultura do milho; b) obter informações para calibração de análise de solo; c) estimar doses econômicas de adubação; d) verificar quais as características do solo que influem na produção. Apenas nitrogênio e fósforo tiveram efeitos significativos na produção do milho. Com o uso desses nutrientes foram obtidos incrementos na produtividade que variaram desde 37 ate 1,137%. Os níveis econômicos de adubacao nitrogenada variaram de 78 a 139 kg/ha de N com uma média de 109 kg/ha de N,. Obtiveram-se níveis críticos de fósforo no solo com valores médios de 8,7 ppm...
Tipo: Boletim de Pesquisa e Desenvolvimento (INFOTECA-E)
Palavras-chave: Fertilização; Análise de solo; Calibração; Fertilization; Analysis.; Milho; Solo; Zea Mays.; Corn; Calibration; Soil.
Ano: 1981
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/132001

High performance liquid chromatographic screening and gas chromatography-nass spectrometry confirmation of tebuthiuron residues in drinking water.
Provedor de dados: 14
Autores: BONATO, P. S.; LANCHOTE, V. L.; DREOSSI, A. de C.
Tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N-dimethylurea) is a phenylurea herbicide used in sugar cane culture for the pre- and post-emergence control of weeds [1,2]. Analysis of tebuthiuron (Figure 1) and of other phenylurea herbicides in environmental samples can be performed by HPLC [3-10], or by gas chromatography using selective detectors such as nitrogen-prosphorus detector (NPD), eletron-capture detector (ECD), or a mass spectrometer (MS) [11-16]. Although Loh et al [17] reported that the use of temperatures above 280oC permits quantitative tebuthiuron breakdown, thus permitting the analysis of the products of decomposition formed, methods based on gas chromatography usually involve a derivatization step to permit analysis of...
Tipo: Fôlder / Folheto / Cartilha (INFOTECA-E)
Palavras-chave: Analysis; Contamination; Residues; Calibration; Environmental impact; Groundwater; Herbicides; Quality control.
Ano: 1999
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/13136

Calibração de pulverizadores terrestres e algumas informações sobre equipamentos para aplicações de defensivos no algodoeiro.
Provedor de dados: 14
Autores: BELTRÃO, N. E. de M.; ARAUJO, J. D. de.
Cuidados, manutencao e principais componentes dos pulverizadores; Calibracao de pulverizadores; Pulverizadores especiais, modernos, munidos de bicos centrífugos ou de bico incorporado "Boozle" eletrodinamico.
Tipo: Circular Técnica (INFOTECA-E)
Palavras-chave: Calibracao; Pulverizadores; Equipamentos; Pulverization.; Algodão; Gossypium Hirsutum.; Calibration; Equipment.
Ano: 1987
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/262768

Radiocarbon Calibration/Comparison Records Based on Marine Sediments from the Pakistan and Iberian Margins
Provedor de dados: 5
Autores: Bard, Edouard; Menot, Guillemette; Rostek, Frauke; Licari, Laetitia; Boening, Philipp; Edwards, R. Lawrence; Cheng, Hai; Wang, Yongjin; Heaton, Timothy J.
We present a new record of radiocarbon ages measured by accelerator mass spectrometry (AMS) on a deep-sea core collected off the Pakistan Margin. The C-14 ages measured on the planktonic foraminifera Globigerinoides ruber from core MD04-2876 define a high and stable sedimentation rate on the order of 50 cm/kyr over the last 50 kyr. The site is distant from the main upwelling zone of the western Arabian Sea where C-14 reservoir age is large and may be variable. Many independent proxies based on elemental analyses, mineralogy, biomarkers, isotopic proxies, and foraminiferal abundances show abrupt changes correlative with Dansgaard-Oeschger and Heinrich events. It is now common knowledge that these climatic events also affected the Arabian Sea during the last...
Tipo: Text
Palavras-chave: Berian Margin; Pakistan Margin; 14C; Calibration.
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00264/37569/35852.pdf

Control of the repeatability of high frequency multibeam echosounder backscatter by using natural reference areas
Provedor de dados: 5
Autores: Roche, Marc; Degrendele, Koen; Vrignaud, Christophe; Loyer, Sophie; Le Bas, Tim; Augustin, Jean-marie; Lurton, Xavier.
The increased use of backscatter measurements in time series for environmental monitoring necessitates the comparability of individual results. With the current lack of pre-calibrated multibeam echosounder systems for absolute backscatter measurement, a pragmatic solution is the use of natural reference areas for ensuring regular assessment of the backscatter measurement repeatability. This method mainly relies on the assumption of a sufficiently stable reference area regarding its backscatter signature. The aptitude of a natural area to provide a stable and uniform backscatter response must be carefully considered and demonstrated by a sufficiently long time-series of measurements. Furthermore, this approach requires a strict control of the acquisition...
Tipo: Text
Palavras-chave: Multibeam echosounder; Seafloor backscatter; Repeatability; Calibration; Reference area; Monitoring.
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00422/53384/54234.pdf

Isoprenoid and branched GDGT-based proxies for surface sediments from marine, fjord and lake environments in Chile
Provedor de dados: 5
Autores: Kaiser, Jerome; Schouten, Stefan; Kilian, Rolf; Arz, Helge W.; Lamy, Frank; Damste, Jaap S. Sinninghe.
Proxies based on glycerol dialkyl glycerol tetraether (GDGT) lipids from archaea [isoprenoid GDGTs] and bacteria [branched (br) GDGTs] in 33 surface sediments from marine, fjord and lake systems between 25°S and 50°S in Chile were analyzed. The regional TEXH86 calibration obtained from the marine and fjord sediments and mean annual surface temperature (T = 59.6 × TEXH86 + 33.0; r2 0.9; n = 23) is statistically identical to the global ocean calibration based on suspended particulate material in terms of slope, but not in terms of intercept. The regional surface and subsurface TEXH86 calibrations were statistically different from the existing global ocean core top calibrations. The TEX86 calibration model based on most of the relatively large lakes studied...
Tipo: Text
Palavras-chave: GDGT; TEX86; BIT; MBT '; CBT; Calibration; Marine; Fjord; Lake; Chile.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00294/40524/39313.pdf

Alkenone distributions in the North Atlantic and Nordic sea surface waters
Provedor de dados: 5
Autores: Sicre, Ma; Bard, E; Ezat, U; Rostek, F.
The C(37)-C(39) alkenones were quantified in suspended particulate matter obtained from the surface waters of the North Atlantic, including the Nordic seas, over a temperature range of 4degrees20 C. U(37)(K') values were linearly correlated to temperature over the entire range covered by our data set, i.e., 420 C (U(37)(K') = 0.027T + 0.036, r(2) = 0.97). The compilation of water column data from the Atlantic, Pacific, and Southern Ocean and Mediterranean Sea suggests that the linear model may not be the best function for fitting U(37)(K') and in situ temperature values. It also shows that suspended matter data from warm waters (T &gt;20degreesC) are still needed to constrain the equation of the global curve. High abundances of C(37: 4) were found in the...
Tipo: Text
Palavras-chave: Alkenones; Paleotemperature; Calibration; Atlantic Ocean; Plankton; Geochemistry; Marine geochemistry; Global change; Biogeochemical processes (4805); Oceanography; Paleoceanography.
Ano: 2002
URL: https://archimer.ifremer.fr/doc/00223/33393/31866.pdf

Recommendations for improved and coherent acquisition and processing of backscatter data from seafloor-mapping sonars
Provedor de dados: 5
Autores: Lamarche, Geoffroy; Lurton, Xavier.
Multibeam echosounders are becoming widespread for the purposes of seafloor bathymetry mapping, but the acquisition and the use of seafloor backscatter measurements, acquired simultaneously with the bathymetric data, are still insufficiently understood, controlled and standardized. This presents an obstacle to well-accepted, standardized analysis and application by end users. The Marine Geological and Biological Habitat Mapping group (Geohab.org) has long recognized the need for better coherence and common agreement on acquisition, processing and interpretation of seafloor backscatter data, and established the Backscatter Working Group (BSWG) in May 2013. This paper presents an overview of this initiative, the mandate, structure and program of the working...
Tipo: Text
Palavras-chave: Multibeam echosounders; Calibration; Reflectivity; Mapping; Seafloor.
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00385/49655/50179.pdf

Comparison of clumped isotope signatures of dolomite cements to fluid inclusion thermometry in the temperature range of 73 to 176 °C
Provedor de dados: 5
Autores: Came, Rosemarie E.; Azmy, Karem; Tripati, Aradhna; Olanipekun, Babatunde-john.
Widespread application of the novel clumped isotope paleothermometer (Δ47) using dolomite samples from shallow crustal settings has been hindered by a lack of adequate constraints on clumped isotope systematics in dolomites that formed at temperatures greater than 50 °C. Consequently, many high-temperature applications involving diagenetic dolomites have required an assumption that the relationship between temperature and Δ47 in diagenetic dolomite resembles the theoretical temperature dependence for calcite. Here we present Δ47 results from dolomite cements for which precipitation temperatures were determined independently using fluid inclusion microthermometry. We compare a rock-based “calibration” for samples from the temperature range of ∼73 to 176 °C...
Tipo: Text
Palavras-chave: Clumped isotopes; Dolomite; Calibration.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00357/46791/46657.pdf

Harmonization in the Joint European Research Infrastructure Network for Coastal Observatories -JERICO
Provedor de dados: 5
Autores: Petihakis, George; Petersen, Wilhelm; Nair, Rajesh; Faimali, Marco; Pavanello, Giovanni; Boukerma, Kada; Delauney, Laurent; Puillat, Ingrid; Farcy, Patrick; Greenwood, Naomi.
The JERICO European research infrastructure (RI) is integrating diverse platform types such as fixed buoys, piles, moorings, drifters, FerryBoxes, gliders, HF radars, coastal cable observatories and the associated technologies dedicated to observe and monitor coastal European seas. The first steps of setting up, coordination and harmonization were done during 2011 to 2015 in the framework of FP7-JERICO (www.jerico-fp7.eu), a 4-year long infrastructure project co-funded by the European Commission with 27 partners from 17 European countries under the coordination of IFREMER. Next steps are driven in the H2020-JERICO-NEXT European project until 2019, involving 33 partners. The main objective of the JERICO consortium is to establish a Pan European approach for...
Tipo: Text
Palavras-chave: Coastal observatories; Harmonization; Biofouling; Calibration; JERICO.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00295/40665/49966.pdf

Backscatter calibration of high-frequency multibeam echosounder using a reference single-beam system, on natural seafloor
Provedor de dados: 5
Autores: Eleftherakis, Dimitrios; Berger, Laurent; Le Bouffant, Naig; Pacault, Anne; Augustin, Jean-marie; Lurton, Xavier.
The calibration of multibeam echosounders for backscatter measurements can be conducted efficiently and accurately using data from surveys over a reference natural area, implying appropriate measurements of the local absolute values of backscatter. Such a shallow area (20-m mean depth) has been defined and qualified in the Bay of Brest (France), and chosen as a reference area for multibeam systems operating at 200 and 300 kHz. The absolute reflectivity over the area was measured using a calibrated single-beam fishery echosounder (Simrad EK60) tilted at incidence angles varying between 0° and 60° with a step of 3°. This reference backscatter level is then compared to the average backscatter values obtained by a multibeam echosounder (here a Kongsberg EM...
Tipo: Text
Palavras-chave: Calibration; Seafloor backscatter; Multibeam echosounder; Single-beam echosounder.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00429/54016/57434.pdf

Calibration of the carbon isotope composition (C-13) of benthic foraminifera
Provedor de dados: 5
Autores: Schmittner, Andreas; Bostock, Helen C.; Cartapanis, Olivier; Curry, William B.; Filipsson, Helena L.; Galbraith, Eric D.; Gottschalk, Julia; Carlos Herguera, Juan; Hoogakker, Babette; Jaccard, Samuel L.; Lisiecki, Lorraine E.; Lund, David C.; Martinez-mendez, Gema; Lynch-stieglitz, Jean; Mackensen, Andreas; Michel, Elisabeth; Mix, Alan C.; Oppo, Delia W.; Peterson, Carlye D.; Repschlaeger, Janne; Sikes, Elisabeth L.; Spero, Howard J.; Waelbroeck, Claire.
The carbon isotope composition (C-13) of seawater provides valuable insight on ocean circulation, air-sea exchange, the biological pump, and the global carbon cycle and is reflected by the C-13 of foraminifera tests. Here more than 1700 C-13 observations of the benthic foraminifera genus Cibicides from late Holocene sediments (C-13(Cibnat)) are compiled and compared with newly updated estimates of the natural (preindustrial) water column C-13 of dissolved inorganic carbon (C-13(DICnat)) as part of the international Ocean Circulation and Carbon Cycling (OC3) project. Using selection criteria based on the spatial distance between samples, we find high correlation between C-13(Cibnat) and C-13(DICnat), confirming earlier work. Regression analyses indicate...
Tipo: Text
Palavras-chave: Carbon; Isotopes; Benthic; Foraminifera; Calibration.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00661/77326/78788.pdf

Identification of the main processes underlying ecosystem functioning in the Eastern English Channel, with a focus on flatfish species, as revealed through the application of the Atlantis end-to-end model
Provedor de dados: 5
Autores: Girardin, Raphael; Fulton, Elizabeth A.; Lehuta, Sigrid; Rolland, Marie; Thebaud, Olivier; Travers-trolet, Morgane; Vermard, Youen; Marchal, Paul.
The ecosystem model Atlantis was used to investigate the key dynamics and processes that structure the Eastern English Channel ecosystem, with a particular focus on two commercial flatfish species, sole (Solea solea) and plaice (Pleuronectes platessa). This complex model was parameterized with data collected from diverse sources (a literature review, survey data, as well as landings and stock assessment information) and tuned so both simulated biomass and catch fit 2002–2011 observations. Here, the outputs are mainly presented for the two focus species and for some other vertebrates found to be important in the trophic network. The calibration process revealed the importance of coastal areas in the Eastern English Channel and of nutrient inputs from...
Tipo: Text
Palavras-chave: Ecosystem modelling; Flatfish fisheries; Trophic relationships; Calibration; Atlantis; Eastern English Channel.
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00354/46524/46289.pdf

An Updated Geophysical Model for AMSR-E and SSMIS Brightness Temperature Simulations over Oceans
Provedor de dados: 5
Autores: Zabolotskikh, Elizaveta; Mitnik, Leonid; Chapron, Bertrand.
In this study, we considered the geophysical model for microwave brightness temperature (BT) simulation for the Atmosphere-Ocean System under non-precipitating conditions. The model is presented as a combination of atmospheric absorption and ocean emission models. We validated this model for two satellite instruments-for Advanced Microwave Sounding Radiometer-Earth Observing System (AMSR-E) onboard Aqua satellite and for Special Sensor Microwave Imager/Sounder (SSMIS) onboard F16 satellite of Defense Meteorological Satellite Program (DMSP) series. We compared simulated BT values with satellite BT measurements for different combinations of various water vapor and oxygen absorption models and wind induced ocean emission models. A dataset of clear sky...
Tipo: Text
Palavras-chave: Calibration; Geophysical model; Numerical simulation; SSMIS; AMSR-E; Satellite passive microwave.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00190/30101/28628.pdf

The EGIM, a generic instrumental module to equip EMSO observatories
Provedor de dados: 5
Autores: Lanteri, Nadine; Legrand, Julien; Moreau, Bertrand; Lagadec, Jean-romain; Rolin, Jean-francois.
The EGIM aims to set up a number of ocean locations where the same set of core variables, including temperature, conductivity, pressure, dissolved O2, turbidity, ocean currents, and passive acoustics, are measured homogeneously: using identical hardware, the same sensor references, the same qualification methods, the same calibration methods, the same data format and access, and the same maintenance procedures. The EGIM provides all the services required to ensure the best measurement quality and long-term reliability in line with the Best Practices Handbook by FIXO3 and ESONET-EMSO Label, these services being sensor power distribution, time stamping, data storage and backup, protection against the environment and against fouling and bi-directional...
Tipo: Text
Palavras-chave: Europe; Instruments; Calibration; Metrology; Sea measurements; Oceans; Observatories.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00427/53881/54949.pdf

Verification and recalibration of HY-2A microwave radiometer brightness temperature
Provedor de dados: 5
Autores: Zhao, Yili; Li, Huimin; Chen, Chuntao; Zhu, Jianhua.
HY-2A is the first one of the Chinese HY-2 ocean satellite series carrying a microwave radiometer (RM) to measure sea surface temperature, sea surface wind speed, atmospheric water vapor, cloud liquid water content, and rain rate. We verified the RM level 1B brightness temperature (T-B) to retrieve environmental parameters. In the verification, T-B that simulated using the ocean-atmosphere radiative transfer model (RTM) was used as a reference. The total bias and total standard deviation (SD) of the RM level 1B T-B, with reference to the RTM simulation, ranged -20.6-4.38 K and 0.7-2.93 K, respectively. We found that both the total bias and the total SD depend on the frequency and polarization, although the values for ascending and descending passes arc...
Tipo: Text
Palavras-chave: HY-2A; Microwave radiometer; Brightness temperature (T-B); Verification; Calibration.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00503/61427/65584.pdf

Intercalibration of benthic flux chambers II. Hydrodynamic characterization and flux comparisons of 14 different designs
Provedor de dados: 5
Autores: Tengberg, Anders; Hall, P; Andersson, U; Linden, B; Styrenius, O; Boland, G; De Bovee, F; Carlsson, B; Ceradini, S; Devol, A; Duineveld, G; Friemann, J; Glud, R; Khripounoff, Alexis; Leather, J; Linke, P; Lund Hansen, L; Rowe, G; Santschi, P; De Wilde, P; Witte, U.
We have compared 14 different sediment incubation chambers, most of them were used on bottom landers. Measurements of mixing time, pressure gradients at the bottom and Diffusive Boundary Layer thickness (DBL) were used to describe the hydrodynamic properties of the chambers and sediment-water solute fluxes of silicate (34 replicates) and oxygen (23 replicates) during three subsequently repeated incubation experiments on a homogenized, macrofauna-free sediment. The silicate fluxes ranged from 0.24 to 1.01 mmol m(-2) day(-1) and the oxygen fluxes from 9.3 to 22.6 mmol m(-2) day(-1). There was no statistically significant correlation between measured fluxes and the chamber design or between measured fluxes and hydrodynamic settings suggesting that type of...
Tipo: Text
Palavras-chave: Comparative flux incubations; Hydrodynamic properties; Calibration; Benthic chambers.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-750.pdf

Fast hydrodynamic model for medium- and long-term dispersion in seawater in the English Channel and southern North Sea, qualitative and quantitative validation by radionuclide tracers
Provedor de dados: 5
Autores: Bailly Du Bois, Pascal; Dumas, Franck.
The database for medium- and long-term model validation using Sb-125 released by the La Hague reprocessing plant includes 1400 measurements performed between 1987 and 1994 in the English Channel and the North Sea and data for each release since 1982. Antimony-125 has a conservative behaviour in water masses over a period of several years. These data can be used qualitatively and quantitatively to compare the measured concentrations with the calculated ones and quantities of tracers. Tritium measurements are also available for model calibration.   A two-dimensional hydrodynamic model has been developed to allow repetitive long-term simulations. This model uses a database of residual tidal currents calculated using the Lagrangian barycentric method [Salomon,...
Tipo: Text
Palavras-chave: North Sea; English Channel; European Continental Shelf; Tritium; Sb 125; Radioactive tracer; Wind stress; Calibration; Modelling.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-731.pdf

A framework to quantify uncertainties of seafloor backscatter from swath mapping echosounders
Provedor de dados: 5
Autores: Malik, Mashkoor; Lurton, Xavier; Mayer, Larry.
Multibeam echosounders (MBES) have become a widely used acoustic remote sensing tool to map and study the seafloor, providing co-located bathymetry and seafloor backscatter. Although the uncertainty associated with MBES-derived bathymetric data has been studied extensively, the question of backscatter uncertainty has been addressed only minimally and hinders the quantitative use of MBES seafloor backscatter. This paper explores approaches to identifying uncertainty sources associated with MBES-derived backscatter measurements. The major sources of uncertainty are catalogued and the magnitudes of their relative contributions to the backscatter uncertainty budget are evaluated. These major uncertainty sources include seafloor insonified area (1–3 dB),...
Tipo: Text
Palavras-chave: Multibeam echosounder; Calibration; Incidence angle.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00429/54018/57435.pdf

Estimated reservoir ages of the Black Sea since the last glacial
Provedor de dados: 5
Autores: Kwiecien, O.; Arz, H. W.; Lamy, F.; Wulf, S.; Bahr, A.; Roehl, U.; Haug, G. H.
Accelerator mass spectrometry (AMS) radiocarbon dating of ostracod and gastropod shells from the southwestern Black Sea cores combined with tephrochronology provides the basis for studying reservoir age changes in the late-glacial Black Sea. The comparison of our data with records from the northwestern Black Sea shows that an apparent reservoir age of similar to 1450 C-14 yr found in the glacial is characteristic of a homogenized water column. This apparent reservoir age is most likely due to the hardwater effect. Though data indicate that a reservoir age of similar to 1450 C-14 yr may have persisted until the Bolling-Allerod warm period, a comparison with the GISP2 ice-core record suggests a gradual reduction of the reservoir age to similar to 1000 C-14...
Tipo: Text
Palavras-chave: Mediterranean abyssal sediments; Minoan eruption; Tephra layers; Radiocarbon; Santorini; Deglaciation; History; Variability; Calibration; Resolution.
Ano: 2008
URL: https://archimer.ifremer.fr/doc/00209/31990/30430.pdf

An Unstructured Numerical Model to Study Wind-Driven Circulation Patterns in a Managed Coastal Mediterranean Wetland: The Vaccares Lagoon System
Provedor de dados: 5
Autores: Boutron, Olivier; Bertrand, Olivier; Fiandrino, Annie; Hoehener, Patrick; Sandoz, Alain; Cherain, Yves; Coulet, Eric; Chauvelon, Philippe.
The spatiotemporal structure of wind-driven circulation patterns and associated water exchanges can drive important bio-hydrodynamic interactions in shallow lagoons. The Vaccares lagoon system is a complex shallow hydrosystem located in the central part of the Rhone Delta (France). It is internationally recognized as part of a biosphere reserve within the framework of UNESCO's Man and Biosphere Programme, and as a RAMSAR site. Due to its frequent occurrence in this area, and considering the shallowness of the Vaccares lagoon system, wind is assumed to play a major role in the hydrodynamic and biological processes. In this study, a hydrodynamic model was developed to investigate the structure of wind-driven circulations in the Vaccares lagoon system, to...
Tipo: Text
Palavras-chave: Coastal lagoon; Mathematical model; Hydrodynamics; Calibration; Validation; Wind-driven circulation.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00303/41382/40558.pdf

Sensitivity analysis of the AquaCrop parameters for rainfed corn in the South of Brazil
Provedor de dados: 86
Autores: Martini,Luiz Carlos Pittol.
Abstract: The objective of this work was to perform a sensitivity analysis of the main input parameters required for the AquaCrop water balance model, using biomass and grain yield data of a rainfed-simulated corn crop, obtained along the climate data series of 1987-2016 in the South of Brazil. The levels of soil-water stress and the depths of maximum effective rooting were the input parameters that most affected the biomass and grain yields simulated by the model, followed by the crop coefficient, water-use efficiency, soil water storage capacity, and contribution of groundwater to water availability in the root zone. The parameters crop cycle duration, plant density, pattern of soil-water extraction, and field surface practices showed little or no impact...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Calibration; Crop model; Drought; Simulation; Soil-water balance; Soil-water stress.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2018000800934

Can Calibration Reconcile Stated and Observed Preferences?
Provedor de dados: 31
Autores: Norwood,   F. Bailey.
Hypothetical bias is a pervasive problem in stated-preference experiments.  Recent research has developed two empirically successful calibrations to remove hypothetical bias, though the calibrations have not been tested using the same data or in a conjoint analysis.  This study compares the two calibrations in a conjoint analysis involving donations to a public good.  Results find the calibrations are biased predictors of true donations but that calibrated and uncalibrated models together provide upper and lower bounds to true donations.
Tipo: Journal Article
Palavras-chave: Calibration; Experimental economics; Forecasting; Hypothetical bias; Public goods; Stated preference; Voluntary contributions; Research Methods/ Statistical Methods; Q51; H41.
Ano: 2005
URL: http://purl.umn.edu/43735

A PROGRAMAÇÃO MATEMÁTICA POSITIVA COMO INSTRUMENTO DE CALIBRAÇÃO E PRESCRIÇÃO DOS MODELOS DE OFERTA AGRÍCOLA
Provedor de dados: 31
Autores: Fragoso,   Rui Manuel de Sousa; Carvalho,   Maria Leonor da Silva; Henriques,   Pedro Damiao de Sousa.
Neste artigo avalia-se a capacidade de calibração e de prescrição de resultados de um modelo de oferta agrícola da Região Alentejo. A capacidade de calibração é analisada para o regime de preços e de ajudas agrícolas em vigor no ano 2000, comparando os resultados de diferentes formas de especificação da função dos custos variáveis totais do modelo de programação matemática positiva com os resultados do modelo tradicional de programação linear e com os dados estatísticos observados. Depois de calibrado, o modelo de programação matemática positiva foi utilizado na prescrição dos resultados relativos ao cenário de preços e ajudas em vigor no ano de 2004. Concluiu-se que a programação matemática positiva para além de ser um eficaz instrumento de calibração dos...
Tipo: Conference Paper or Presentation
Palavras-chave: Programação matemática positiva; Oferta agrícola; Calibração; Prescrição; Positive mathematical programming; Agricultural supply; Calibration; Prescription; Agribusiness.
Ano: 2008
URL: http://purl.umn.edu/108610

Benefit Transfer as Preference Calibration
Provedor de dados: 31
Autores: Smith,   V. Kerry; van Houtven,   George; Pattanayak,   Subhrendu K.
This paper proposes and illustrates the use of a new approach to benefit transfer for the non-market valuation of environmental resources. It treats transfer as an identification problem that requires assessing whether available benefit estimates permit the parameters of a preference function to be identified. The transfer method proposed uses these identifying restrictions to calibrate preference parameters and bases the benefit estimates on that preference function. The approach is illustrated using travel cost, hedonic and contingent valuation estimates, as well as combinations of estimates. It has three potential advantages over conventional practice: (1) it allows multiple, potentially overlapping estimates of the benefits of an improvement in...
Tipo: Working or Discussion Paper
Palavras-chave: Benefit transfer; Calibration; Non-market valuation; Environmental Economics and Policy; D61; Q20; H40.
Ano: 1999
URL: http://purl.umn.edu/10607

Calibration and Validation of SWAT for the Upper Maquoketa River Watershed
Provedor de dados: 31
Autores: Kanwar,   Ramesh S.; Reungsang,   Pipat; Jha,   Manoj K.; Gassman,   Philip W.; Ahmad,   Khalil; Saleh,   Ali.
A validation study has been performed using the Soil and Water Assessment Tool (SWAT) model with data collected for the Upper Maquoketa River Watershed (UMRW), which drains over 16,000 ha in northeast Iowa. This validation assessment builds on a previous study with nested modeling for the UMRW that required both the Agricultural Policy EXtender (APEX) model and SWAT. In the nested modeling approach, edge-of-field flows and pollutant load estimates were generated for manure application fields with APEX and were then subsequently routed to the watershed outlet in SWAT, along with flows and pollutant loadings estimated for the rest of the watershed routed to the watershed outlet. In the current study, the entire UMRW cropland area was simulated in SWAT, which...
Tipo: Working or Discussion Paper
Palavras-chave: Calibration; Modeling; Nitrate; SWAT; Validation; Water quality; Resource /Energy Economics and Policy.
Ano: 2005
URL: http://purl.umn.edu/18440

THE CALIBRATION OF INCOMPLETE DEMAND SYSTEMS IN QUANTITATIVE ANALYSIS
Provedor de dados: 31
Autores: Beghin,   John C.; Bureau,   Jean-Christophe; Drogue,   Sophie.
We introduce an easily implemented and flexible calibration technique for partial demand systems, combining recent developments in incomplete demand systems and a set of restrictions conditioned on the available elasticity estimates. The technique accommodates various degrees of knowledge on cross-price elasticities, satisfies curvature restrictions, and allows the recovery of an exact welfare measure for policy analysis. The technique is illustrated with a partial demand system for food consumption in Korea for different states of knowledge on cross-price effects. The consumer welfare impact of food and agricultural trade liberalization is measured.
Tipo: Conference Paper or Presentation
Palavras-chave: Calibration; Exact welfare measure; Incomplete demand systems; Policy analysis.; Demand and Price Analysis.
Ano: 2003
URL: http://purl.umn.edu/25820

Calibrating Online Survey Sample for Economic Impact Analysis
Provedor de dados: 31
Autores: Devkota,   Nirmala; Paudel,   Krishna P.; Fannin,   James Matthew; Hall,   Larry M.; Caffey,   Rex H.
Online surveys have emerged as low-cost data collection approach in empirical researches; however, the validity of data remains questionable. Therefore, we employed a stochastic frontier estimation method to calibrate online recreational expenditure. Study results suggested the presence of inefficiency on online surveys. Analysis was extended to estimate economic impact of nature based recreation on a local economy.
Tipo: Conference Paper or Presentation
Palavras-chave: Calibration; Online survey; Onsite survey; Stochastic frontier approach; Research Methods/ Statistical Methods; Resource /Energy Economics and Policy.
Ano: 2007
URL: http://purl.umn.edu/34997

A BAYESIAN ALTERNATIVE TO GENERALIZED CROSS ENTROPY SOLUTIONS FOR UNDERDETERMINED ECONOMETRIC MODELS
Provedor de dados: 31
Autores: Heckelei,   Thomas; Mittelhammer,   Ronald C.; Jansson,   Torbjorn.
This paper presents a Bayesian alternative to Generalized Maximum Entropy (GME) and Generalized Cross Entropy (GCE) methods for deriving solutions to econometric models represented by underdetermined systems of equations. For certain types of econometric model specifications, the Bayesian approach provides fully equivalent results to GME-GCE techniques. However, in its general form, the proposed Bayesian methodology allows a more direct and straightforwardly interpretable formulation of available prior information and can reduce significantly the computational effort involved in finding solutions. The technique can be adapted to provide solutions in situations characterized by either informative or uninformative prior information.
Tipo: Working or Discussion Paper
Palavras-chave: Underdetermined Equation Systems; Maximum Entropy; Bayesian Priors; Structural Estimation; Calibration; Research Methods/ Statistical Methods; C11; C13; C51.
Ano: 2008
URL: http://purl.umn.edu/56973

THE CALIBRATION OF INCOMPLETE DEMAND SYSTEMS IN QUANTITATIVE ANALYSIS
Provedor de dados: 31
Autores: Beghin,   John C.; Bureau,   Jean-Christophe; Drogue,   Sophie.
We introduce an easily implemented and flexible calibration technique for partial demand systems, combining recent developments in incomplete demand systems and a set of restrictions conditioned on the available elasticity estimates. The technique accommodates various degrees of knowledge on cross-price elasticities, satisfies curvature restrictions, and allows the recovery of an exact welfare measure for policy analysis. The technique is illustrated with a partial demand system for food consumption in Korea for different states of knowledge on cross-price effects. The consumer welfare impact of food and agricultural trade liberalization is measured.
Tipo: Working or Discussion Paper
Palavras-chave: Calibration; Exact welfare measure; Incomplete demand systems; Policy analysis; Demand and Price Analysis.
Ano: 2003
URL: http://purl.umn.edu/18462

Water Quality Modeling for the Raccoon River Watershed Using SWAT
Provedor de dados: 31
Autores: Jha,   Manoj K.; Arnold,   Jeffrey G.; Gassman,   Philip W.
The Raccoon River Watershed (RRW) in West-Central Iowa has been recognized as exporting some of the highest nitrate-nitrogen loadings in the United States and is a major source of sediment and other nutrient loadings. An integrated modeling framework has been constructed for the RRW that consists of the Soil and Water Assessment Tool (SWAT) model, the interactive SWAT (i_SWAT) software package, Load Estimator (LOADEST) computer program, and other supporting software and databases. The simulation framework includes detailed land use and management data such as different crop rotations and an array of nutrient and tillage management schemes, derived from the U.S. Department of Agriculture's National Resources Inventory databases and other sources. This paper...
Tipo: Working or Discussion Paper
Palavras-chave: Calibration; Management practices; Raccoon River Watershed; SWAT; Resource /Energy Economics and Policy.
Ano: 2006
URL: http://purl.umn.edu/18455

BANANA CULTIVAR TRIALS FOR FRUIT PRODUCTION, ORNAMENTAL-LANDSCAPE USE, AND ORNAMENTAL-NURSERY PRODUCTION IN SOUTH GEORGIA
Provedor de dados: 31
Autores: Fonsah,   Esendugue Greg; Krewer,   Gerard; Rieger,   Mark.
North America is the largest net importer of bananas on a regional basis. The United States is still the world’'s number- one importer and consumer of bananas. U.S. companies spend approximately $1.1 billion each year on banana imports, purchasing 31.1% of total world imports (Fonsah 2002; FAO 2001). Bananas and plantains together have been rated the fourth most important crop in the world in terms of food value and food security. This research is aimed at determining the feasibility and suitability of Annual Cropping Production (ACP) for a niche market under Georgia weather conditions and, determining which cultivars have the greatest potential for ornamental-landscape use and ornamental-nursery production. Phenological and pomological sampling and data...
Tipo: Journal Article
Palavras-chave: Banana; Cultivars; Input application; Fertility; Field operations; Production; Marketing; Quality; Landscape; Green industry; Finger length; Calibration; Pseudo-stem; Crop Production/Industries.
Ano: 2004
URL: http://purl.umn.edu/27149

Think Again: Higher Elasticity of Substitution Increases Economic Resilience
Provedor de dados: 31
Autores: Dumas,   Patrice; Hallegatte,   Stephane.
This paper shows that, counter-intuitively, a higher elasticity of substitution in model production function can lead to reduced economic resilience and larger vulnerability to shocks in production factor prices. This result is due to the fact that assuming a higher elasticity of substitution requires a recalibration of the production function parameters to keep the model initial state unchanged. This result has consequences for economic analysis, e.g., on the economic vulnerability to climate change.
Tipo: Working or Discussion Paper
Palavras-chave: Substitution; Calibration; Constant Elasticity of Substitution; Shock; Risk and Uncertainty; D24; E17; E23.
Ano: 2009
URL: http://purl.umn.edu/54283

Aggregation and Calibration of Agricultural Sector Models Through Crop Mix Restrictions and Marginal Profit Adjustments
Provedor de dados: 31
Autores: Wiborg,   Torben; McCarl,   Bruce A.; Rasmussen,   Svend; Schneider,   Uwe A.
All agricultural sector models must deal with aggregation and calibration somehow. The aggregation problem involves treating a group of producers as if they all responded in the same way as a single representative unit. The calibration problem concerns making a model reproduce as closely as possible an empirically observed set of decision maker actions. This paper shows how both calibration and aggregation are addressed through crop mix restrictions combined with marginal profit adjust-ments.
Tipo: Conference Paper or Presentation
Palavras-chave: Mathematical programming; Aggregation; Calibration; Crop mix; Marginal cost; Agricultural sector model; Agribusiness; C6; C61; Q1; Q11; Q17; Q18; R12; R13; R14.
Ano: 2005
URL: http://purl.umn.edu/24567

Properties of Flexible Functional Forms for Modeling Bilateral Export Supply and Import Demand in Multi-Country Agri-Food Models
Provedor de dados: 31
Autores: Winter,   Etti Maria; Frohberg,   Klaus.
This paper illustrates the opportunities of incorporating more advanced functional forms into multi-country trade policy models. It suggests the use of flexible forms such as the Symmetric Generalized McFadden Function (SGMF) or the Normalized Quadratic-Quadratic Expenditure System (NQQES). Particularly if issues namely trade in differentiated products, preferential trade and effects of standards and traceability on bilateral trade are considered the NQQES offers attractive properties since it allows estimating variety specific expenditure elasticities which might compensate for example increased certification costs. A second aim of the paper refers to the critique on the handling of model parameters in calibrated policy models. In general, employed...
Tipo: Conference Paper or Presentation
Palavras-chave: Bilateral trade modelling; Flexible functions; Calibration; International Relations/Trade; Research Methods/ Statistical Methods; B41; C61; F13; Q18; Q17.
Ano: 2005
URL: http://purl.umn.edu/24471

Welfare impacts of alternative biofuel and energy policies
Provedor de dados: 31
Autores: Cui,   Jingbo; Lapan,   Harvey E.; Moschini,   GianCarlo; Cooper,   Joseph C.
We employ an open economy general equilibrium model to investigate the effects of government energy policy, with emphasis on corn-based ethanol, on the U.S. economy. The model specification incorporates world and domestic markets, assumes pollution costs from fuel consumption, and allows endogenous determination of equilibrium quantities and prices for oil, corn and ethanol. The model is calibrated to represent a recent benchmark data set for 2009 and is used to simulate the positive and normative effects of alternative policies. We find that a second best policy of a fuel tax and ethanol subsidy approximates fairly closely the welfare gains associated with the first best policy (optimal carbon tax and tariffs on traded goods).The largest economic gains to...
Tipo: Conference Paper or Presentation
Palavras-chave: Biofuel; Calibration; Welfare; Second Best Policies; Agricultural and Food Policy; Resource /Energy Economics and Policy.
Ano: 2010
URL: http://purl.umn.edu/61138

Dielectric constant obtained from TDR and volumetric moisture of soils in southern Brazil
Provedor de dados: 90
Autores: Kaiser,Douglas Rodrigo; Reinert,Dalvan José; Reichert,José Miguel; Minella,Jean Paollo Gomes.
Soil moisture is the property which most greatly influences the soil dielectric constant, which is also influenced by soil mineralogy. The aim of this study was to determine mathematical models for soil moisture and the dielectric constant (Ka) for a Hapludalf, two clayey Hapludox and a very clayey Hapludox and test the reliability of universal models, such as those proposed by Topp and Ledieu and their co-workers in the 80's, and specific models to estimate soil moisture with a TDR. Soil samples were collected from the 0 to 0.30 m layer, sieved through a mesh of 0.002 m diameter and packed in PVC cylinders with a 0.1 m diameter and 0.3 m height. Seven samples of each soil class were saturated by capillarity and a probe composed of two rods was inserted in...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Mathematical models; Soil moisture; TDR; Calibration.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832010000300006

Potassium Fertilization for Long Term No-Till Crop Rotation in the Central-Southern Region of Paraná, Brazil
Provedor de dados: 90
Autores: Vieira,Renan Costa Beber; Fontoura,Sandra Mara Vieira; Bayer,Cimélio; Moraes,Renato Paulo de; Carniel,Eduardo.
ABSTRACT Fertilization programs for annual crops in the state of Paraná, southern Brazil, are based on studies that focused on conventional tillage and were established more than 30 years ago. The primary purpose of this study was to assess potassium (K) fertilization on long-term (&gt;30 years) no-tillage soybean, corn, wheat, and barley crops grown in rotation on Oxisols in the central-southern region of Paraná. A total of 47 experiments were carried out from 2008 to 2013, three of which addressed K calibration and the other 44, crop response to K fertilization. Critical K soil-test value and interpretation classes were established from the ratio between relative crop yield [RY = (yield without K/max yield) × 100] and soil K levels. Winter cereals were...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Calibration; Critical level; Mehlich-1.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832016000100538

Development and evaluation of an automated system for testing current meters
Provedor de dados: 91
Autores: Saretta,Ezequiel; Camargo,Antonio P. de; Botrel,Tarlei A.; Pinto,Marinaldo F.; Katsurayama,Geancarlo T.; Frizone,José A.
ABSTRACT Current meters are equipment widely used for estimating flow velocity in rivers and streams. Periodic calibrations of current meters are important to ensure the quality of measurements, but the required testing facilities are complex and only available in a few institutions. However, advances in electronics and automation may contribute to developing simple and reliable calibration systems. Thus, this study aimed to develop an automated system for testing current meters, which consisted of a trapezoidal channel, a step motor, a tow car and a management system, composed of a supervisory application and microprocessed modules to control the motor and the data acquisition. Evaluations of the displacement velocity showed that it matched the reference...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hydrometry; Electronics; Automation; Calibration.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016000200181

Mixed effect models for predicting breast height diameter from stump diameter of Oriental beech in Göldağ
Provedor de dados: 63
Autores: Ercanli,Ilker; Gunlu,Alkan; Başkent,Emin Zeki.
Diameter at breast height (DBH) is the simplest, most common and most important tree dimension in forest inventory and is closely correlated with wood volume, height and biomass. In this study, a number of linear and nonlinear models predicting diameter at breast height from stump diameter were developed and evaluated for Oriental beech (Fagus orientalisLipsky) stands located in the forest region of Ayancık, in the northeast of Turkey. A set of 1,501 pairs of diameter at breast height-stump measurements, originating from 70 sample plots of even-aged Oriental beech stands, were used in this study. About 80 % of the otal data (1,160 trees in 55 sample plots) was used to fit a number of linear and nonlinear model parameters; the remaining 341 trees in 15...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: DBH; Prediction; Random parameters; Calibration.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162015000300245

Neutron probe calibration correction by temporal stability parameters of soil water content probability distribution
Provedor de dados: 63
Autores: Reichardt,K.; Portezan,O.; Bacchi,O.O.S.; Oliveira,J.C.M; Dourado-Neto,D.; Pilotto,J.E.; Calvache,M.
A neutron probe calibration correction is proposed in order to reduce soil water content variability, assumed to be a consequence of improper calibrations relations. The time stability of spatially measured soil water content data is used to correct the intercepts of linear calibration relations. This procedure reduced the coefficients of variation of soil water content data from 4 to less than 2% in a Rhodic Kanhapludalf.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Soil water content; Neutron probe; Calibration; Time stability; Spatial variability.
Ano: 1997
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161997000300003

Non-destructive determination of photosynthetic pigments in the leaves of castor oil plants - doi: 10.4025/actasciagron.v34i3.13872
Provedor de dados: 1
Autores: Rigon, João Paulo Gonsiorkiewicz; Faculdade de Ciências Agronômicas, Universidade Estadual Paulista; Capuani, Silvia; Faculdade de Ciências Agronômicas, Universidade Estadual Paulista; Beltrão, Napoleão de Esberard Macêdo; Faculdade de Ciências Agronômicas, Universidade Estadual Paulista; Brito Neto, José Félix; Faculdade de Ciências Agronômicas, Universidade Estadual Paulista; Sofiatti, Valdinei; Empresa Brasileira de Pesquisa Agropecuária; França, Fabíola Vanessa; Faculdade de Ciências Agronômicas, Universidade Estadual Paulista.
The aim of the present work was to determine the relationship between photosynthetic pigments extracted in dimethyl sulfoxide (DMSO) and readings obtained by the portable chlorophyll meter, ClorofiLOG® 1030, to generate mathematical models that are able to report the contents of chlorophyll and carotenoids in the leaves of the castor oil plant. This work was conducted at Embrapa Cotton, located in the city of Campina Grande, state of Paraíba, Brazil, in October 2010. For the indirect analysis, portable equipment was used to read leaf discs of different shades of green. The chlorophyll in these discs was then determined using a classical method: 5 mL of DMSO was added, the samples were incubated in a water bath at 70ºC for 30 minutes, and a 3 mL aliquot was...
Palavras-chave: 5.01.00.00-9 chlorophyll meter; Calibration; Chlorophyll 5.01.03.00-8.
Ano: 2012
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/13872

Calibration and validation of the aquacrop model for the culture lettuce (lactuca sativa l.) under fertilization levels in pluvial condition
Provedor de dados: 111
Autores: Amirouche, mawhoub.
The search for decision-making tools is essential in order to control agricultural practices and plan for sustainable agriculture that respects the environment. To this end, FAO has developed an evaluation model called AquaCrop, which covers most technical routes, including fertilization. In this perspective, this study focuses on the AquaCrop model (v6.1) to calibrate it for the simulation of lettuce crop yields (Lactuca sativa L), under different fertilization levels for the trial periods (2015/2016) and (2016/2017). Four levels of fertilization were examined under rain conditions, namely T1 (0 kg N/ha), T2 (60 kg N/ha), T3 (120 kg N/ha) and T4 (180 kg N/ha). The model performance was evaluated using the coefficient of determination (R2), the square root...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: AquaCrop; Lettuce; Calibration; Validation; Fertility stress; Water productivity.
Ano: 2021
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/6195

Nondestructive quality assessment of longans using near infrared hyperspectral imaging
Provedor de dados: 111
Autores: SAHACHAIRUNGRUENG, WORANITTA; TEERACHAICHAYUT, SONTISUK.
Near infrared hyperspectral imaging (NIR-HSI) is a method that can be used to evaluate quality of fruit nondestructively. The objective of this research was to study the feasibility of NIR-HSI reflectance mode, within the wavelength of 935-1720 nm, for predicting quality of longans. The two important factors chosen were: total soluble solids (TSS) and moisture content (MC). Each longan was assessed by first measuring its spectral data then measuring its TSS and MC to establish calibration models using multiple linear regression (MLR) compared with partial least squares regression (PLSR). Original spectra of longans gave the optimum results by PLSR for developing the models with correlation coefficients (Rp) of 0.76 for TSS and 0.88 for MC as well as root...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Spectra; Nondestructive; Calibration; Prediction; Images.
Ano: 2022
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/7203

Development of deficit irrigation for maize crop under drip irrigation in samaru-nigeria
Provedor de dados: 111
Autores: Ezekiel, Oiganji.
In the past, outcome of any water management strategy could only be known after field experiment, in recent times, means of evaluating the implications of irrigation schedules without field experiment is fast gaining grounds with the use of models.  This research work present a scenarios studies for different developed irrigation scheduling options for a drip irrigated maize crop at the Institute for Agricultural Research (IAR) irrigation farm Samaru-Nigeria during 2013 and 2014 cropping season using a computer-based model.  Aqua Crop was calibrated and validated with data obtained from the field, it was further used to generate scenario of different irrigation scheduling outcome. Grain and biomass yields, harvest index, seasonal evapotranspiration and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Agricultural Engineering/ soil and water conservation engineering Aqua Crop model; Calibration; Validation; Irrigation schedulling; Water productivity.
Ano: 2017
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/3752

40Ar/39Ar geochronology at the Instituto de Geociências, USP: instrumentation, analytical procedures, and calibration
Provedor de dados: 42
Autores: VASCONCELOS,PAULO M.; ONOE,ARTUR T.; KAWASHITA,KOJI; SOARES,ADALBERTO J.; TEIXEIRA,WILSON.
Laser heating 40Ar/39Ar geochronology provides high analytical precision and accuracy, mum-scale spatial resolution, and statistically significant data sets for the study of geological and planetary processes. A newly commissioned 40Ar/39Ar laboratory at CPGeo/USP, São Paulo, Brazil, equips the Brazilian scientific community with a new powerful tool applicable to the study of geological and cosmochemical processes. Detailed information about laboratory layout, environmental conditions, and instrumentation provides the necessary parameters for the evaluation of the CPGeo/USP 40Ar/39Ar suitability to a diverse range of applications. Details about analytical procedures, including mineral separation, irradiation at the IPEN/CNEN reactor at USP, and mass...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Geochronology; 40Ar/39Ar method; Irradiation; Calibration.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652002000200008

Three decades of reference evapotranspiration estimates for a tropical watershed in the eastern Amazon
Provedor de dados: 42
Autores: SILVA JÚNIOR,RENATO O. DA; SOUZA,EVERALDO B. DE; TAVARES,ALEXANDRA L.; MOTA,JOSÉ A.; FERREIRA,DOUGLAS B.S.; SOUZA-FILHO,PEDRO W.M.; ROCHA,EDSON J.P. DA.
ABSTRACT This study estimated the reference evapotranspiration rate (ETo) for the Itacaiúnas River Watershed (IRW), Eastern Amazonia, and measured the accuracy of eight empirical equations: Penman-Monteith (PM), Priestley-Taylor (PT), Hargreaves and Samani (HS), Camargo (CAM), Thornthwaite (TH), Hamon (HM), Kharrufa (KF) and Turc (TC) using monthly data from 1980 to 2013. In addition, it verifies the regional applicability to the IRW using a for the Marabá-PA station. The methods TC and PM (FAO56) presented the best results, which demonstrate that radiation and higher temperatures are the dominant drivers in the Evapotranspiration process, while relative humidity and wind speed have a much smaller impact. The temporal and spatial variability of ETo for IRW...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Calibration; Decades; Eastern Amazon; Evapotranspiration; Methods; Watershed.
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652017000501985

Pear quality characteristics by Vis / NIR spectroscopy
Provedor de dados: 42
Autores: Machado,Nicácia P.; Fachinello,José C.; Galarça,Simone P.; Betemps,Débora L.; Pasa,Mateus S.; Schmitz,Juliano D.
Recently, non-destructive techniques such as the Vis / NIR spectroscopy have been used to evaluate the characteristics of maturation and quality of pears. The study aims to validate the readings by the Vis / NIR spectroscopy as a non-destructive way to assess the qualitative characteristics of pear cultivars 'Williams', 'Packams' and 'Carrick', produced according to Brazilian conditions. The experiment was conducted at the Pelotas Federal University, UFPel, in Pelotas / RS, and the instrument used to measure the fruit quality in a non-destructive way was the NIR- Case spectrophotometer (SACMI, Imola, Italy). To determine pears' soluble solids (SS) and pulp firmness (PF), it was established calibration equations for each variety studied, done from the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Calibration; Firmness; Pear; Soluble solids; Validation.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652012000300027

A calorimetry system for metabolism trials
Provedor de dados: 45
Autores: Rodríguez,N.M.; Campos,W.E.; Lachica,M.L.; Borges,I.; Gonçalves,L.C.; Borges,A.L.C.C.; Saliba,E.O.S.
An indirect calorimetry system for rapid determination of CO2 and CH4 production and O2 consumption to estimate heat production of animals was built at Escola de Veterinária da Universidade Federal de Minas Gerais, Brazil. Procedures for determination of correction and calibration factors for gas analyzers and the whole system, using standard test gases were described. In addition, a metabolic trial was performed to evaluate heat production of lambs fed ad libitum. It is concluded that the system is suitable for heat production determinations in small and medium size animals.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Calibration; Open circuit; Respirometry.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-09352007000200033

Utilization of the cropgro-soybean model to estimate yield loss caused by Asian rust in cultivars with different cycle
Provedor de dados: 53
Autores: Rodrigues,Rafael de Ávila; Pedrini,João Eduardo; Fraisse,Clyde William; Fernandes,José Maurício Cunha; Justino,Flávio Barbosa; Heinemann,Alexandre Bryan; Costa,Luiz Cláudio; Vale,Francisco Xavier Ribeiro do.
In recent years, crop models have increasingly been used to simulate agricultural features. The DSSAT (Decision Support System for Agrotechnology Transfer) is an important tool in modeling growth; however, one of its limitations is related to the unaccounted-for effect of diseases. Therefore, the goals of this study were to calibrate and validate the CSM CROPGRO-Soybean for the soybean cultivars M-SOY 6101 and MG/BR 46 (Conquista), analyze the performance and the effect of Asian soybean rust on these cultivars under the environmental conditions of Viçosa, Minas Gerais, Brazil. The experimental data for the evaluation, testing, and adjustment of the genetic coefficients for the cultivars, M-SOY 6101 and MG/BR 46 (Conquista), were obtained during the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: DSSAT; Calibration; Validation; Modeling; Rust epidemics.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052012000200021

Sensitivity of APSIM/ORYZA model due to estimation errors in solar radiation
Provedor de dados: 53
Autores: Heinemann,Alexandre Bryan; van Oort,Pepijn A.J.; Fernandes,Diogo Simões; Maia,Aline de Holanda Nunes.
Crop models are ideally suited to quantify existing climatic risks. However, they require historic climate data as input. While daily temperature and rainfall data are often available, the lack of observed solar radiation (Rs) data severely limits site-specific crop modelling. The objective of this study was to estimate Rs based on air temperature solar radiation models and to quantify the propagation of errors in simulated radiation on several APSIM/ORYZA crop model seasonal outputs, yield, biomass, leaf area (LAI) and total accumulated solar radiation (SRA) during the crop cycle. The accuracy of the 5 models for estimated daily solar radiation was similar, and it was not substantially different among sites. For water limited environments (no irrigation),...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Crop model; Calibration; Upland rice.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052012000400016

Prediction of soil organic matter and clay contents by near-infrared spectroscopy - NIRS
Provedor de dados: 65
Autores: Lazzaretti,Bruno Pedro; Silva,Leandro Souza da; Drescher,Gerson Laerson; Dotto,André Carnieletto; Britzke,Darines; Nörnberg,José Laerte.
ABSTRACT: Among the soil constituents, special attention is given to soil organic matter (SOM) and clay contents, since, among other aspects, they are key factors to nutrient retention and soil aggregates formation, which directly affect the crop production potential. The methods commonly used for the quantification of these constituents have some disadvantages, such as the use of chemical reactants and waste generation. An alternative to these methods is the near-infrared spectroscopy (NIRS) technique. The aim of this research is to evaluate models for SOM and clay quantification in soil samples using spectral data by NIRS. A set (n = 400) of soil samples previously analyzed by traditional methods were used to generate a NIRS calibration curve. The clay...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Calibration; Validation; Mathematical models; Spectral pretreatment.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782020000100251

Hydrological simulation as subside for management of surface water resources at the Mortes River Basin
Provedor de dados: 64
Autores: Eduardo,Eliete Nazaré; Mello,Carlos Rogério de; Viola,Marcelo Ribeiro; Owens,Phillip Ray; Curi,Nilton.
ABSTRACT Hydrological models are tools which describe processes and allow predicting the results of making management decisions, and are an important water resource management tool, especially for small-sized watersheds. This work had as an objective to test different calibration strategies and apply the SWAT model for hydrological simulation of the Mortes River Basin, MG. We evaluated 6 fluviometric stations, with drainage area between 272 and 6070 km² for purposes of water resource management. The evaluation of the model performance was conducted by using Nash-Sutcliffe coefficients (CNS) and percent bias (PBIAS). The results obtained from the statistic indices applied in the analysis of the model performance qualified the SWAT hydrological model as...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Environmental management; SWAT; Drainage area; Calibration.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542016000400390