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Wyszukujesz frazę "variability" wg kryterium: Temat


Tytuł:
Observed variability in physical and biogeochemical parameters in the Central Arabian Gulf
Autorzy:
Rakib, F.
Al-Ansari, E.M.A.S.
Husrevoglu, Y.S.
Yigiterhan, O.
Al-Maslamani, I.
Aboobacker, V.M.
Vethamony, P.
Powiązania:
https://bibliotekanauki.pl/articles/2078929.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
economic zone
Arabian Gulf
vertical variability
spatial variability
temporal variability
water column
dissolved oxygen
hydrography
chlorophyll a
Opis:
In situ measurements of physical and biogeochemical variables were conducted along a transect in the Exclusive Economic Zone (EEZ) of Qatar during late summer (September 2014) and winter (January 2015) to investigate their vertical, spatial and temporal variability. The study reveals that the water column is characterized by strong stratification during late summer in the deepest station, where the water depth is around 65 m and the surface to bottom temperature variation is around 9.1°C. The water column is vertically homogeneous during winter due to surface cooling and wind mixing. The surface to 23 m water column is characterized by ample dissolved oxygen (DO) during late summer and winter in the offshore regions, however, relatively low DO is found during late summer due to weak mixing and advection under weak winds and currents. Dissolved oxygen drops to hypoxic levels below the summer thermocline, and the winter high DO layer extends up to the bottom. Chlorophyll-a (Chl-a) is relatively high during late summer in the offshore region, while that in the nearshore regions is very low, which is linked to the anthropogenic stresses from the central east coast of Qatar. The results identified in this study fill an essential gap in the knowledge of regional primary production dynamics.
Źródło:
Oceanologia; 2021, 63, 2; 227-237
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrogeochemistry and magnitude of SGD in the Bay of Puck, Southern Baltic Sea
Autorzy:
Klostowska, Z.
Szymczycha, B.
Lengier, M.
Zarzeczanska, D.
Dzierzbicka-Glowacka, L.
Powiązania:
https://bibliotekanauki.pl/articles/47678.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
hydrogeochemistry
submarine groundwater discharge
seasonal variability
spatial variability
Puck Bay
Baltic Sea
Źródło:
Oceanologia; 2020, 62, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatial and temporal variability of soil water content
Autorzy:
Oyedele, D.J.
Tijani, F.O.
Powiązania:
https://bibliotekanauki.pl/articles/24729.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
soil water
water content
spatial variability
temporal variability
ploughing
soil layer
Źródło:
International Agrophysics; 2010, 24, 2; 171-176
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatial Variability of Chosen Soil Properties on Mountainous Area on Example of the Kasinczanka Stream Basin, Western Carpathians
Autorzy:
Kruk, E.
Ryczek, M.
Klatka, S.
Malec, M.
Powiązania:
https://bibliotekanauki.pl/articles/123331.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
spatial variability
semivariogram
krigring
geostatistics
Opis:
The phenomenon of erosion on mountain and submontane areas influences directly on high variability of soil properties. In the work there were presented results of analysis of spatial variability of bulk density, total porosity, organic matter content and saturated hydraulic conductivity, on eroded slopes of the Kasińczanka stream basin. Geostatistical analysis was carried out using the kriging method, based on irregular network, consisted of 52 points, situated by means of the GPS. Taking into account the calculated variability coefficient it was stated, that on the investigated area, the most flexible spatially was saturated hydraulic conductivity, while the less flexible turned out total porosity. Using the determined models of semivariance, the maps of spatial variability of chosen parameters were drafted. It was stated that high value of variance influenced on higher smoothing of spatial distribution in interpolation. Results of geostatistical analysis will allow to find locations for new measuring points, what has substantial significance in mountain areas, for precision analysis of soil properties. Based on the obtained results, it can be stated that the kriging method may be useful tool for determination spatial variability analysis of soil properties on an areas of mountain basins.
Źródło:
Journal of Ecological Engineering; 2018, 19, 3; 146-153
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Soil Sequences Along a Slope of the Opalenica Plain
Autorzy:
Kozłowski, M.
Komisarek, J.
Powiązania:
https://bibliotekanauki.pl/articles/123339.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
Luvisols
Retisols
toposequence
spatial variability
Opis:
The paper presents the results of a study on differentiation of the morphological structure of soil and selected physical and chemical properties of soils in toposequence of the Opalenica Plain. The study was conducted in a 1200 m long transect running through a typical soil toposequence for the Polish Lowland, and therefore the results presented in this study can be extrapolated to similar geomorphological conditions of the area. On the basis of pedological cross-section, the following soil units were distinguished: PWspgl – Albic Luvisols (Arenic) with glossic properties, PAt – Albic Glossic Retisols (Loamic), PAsp – Albic Glossic Retisols (Aric, Arenic), PAspgg – Albic Glossic Retisols (Aric, Arenic, Oxyaquic), PWsggl – Albic Luvisols (Aric, Arenic, Stagnic) with glossic properties, PWgggl – Albic Luvisols (Aric, Loamic, Stagnic) with glossic properties, CZgg – Mollic Reductigleyic Eutric Gleysols (Aric, Loamic), CFt – Fluvic Phaeozems (Aric, Arenic). Each of these units has its own specific position in toposequence but the occurrence of Fluvic Phaeozems (Aric, Arenic) are associated with geogenetic processes of Mogilnica river. In this work, using a multiple regression analysis a statistically significant relationships between the position of the soils in relief and the terrain slopes and the organic carbon content in Ap horizon, the cation exchangeable capacity, the sum of exchangeable bases and the pH were obtained. Systematic variability of most soil properties of Ap horizon have shown two distances of spatial variation. The first concerns the systematic changes in shorter distance (from 132 to 344 m) and can be associated with differences in soil properties between separate soil units. The second distance of spatial correlation ranges from 431 m to 792 m, which testify to the fact that quantitative changes in the properties of soils are realized gradually and distinctly, together with the differentiation of the slope, over several separate cartographic units.
Źródło:
Journal of Ecological Engineering; 2016, 17, 1; 69-76
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Technical note: Comparison between two methods for estimating the vertical scale of fluctuation for modeling random geotechnical problems
Autorzy:
Pieczyńska-Kozłowska, J.
Powiązania:
https://bibliotekanauki.pl/articles/178384.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
scale of fluctuation
spatial variability
Opis:
The design process in geotechnical engineering requires the most accurate mapping of soil. The difficulty lies in the spatial variability of soil parameters, which has been a site of investigation of many researches for many years. This study analyses the soilmodeling problem by suggesting two effective methods of acquiring information for modeling that consists of variability from cone penetration test (CPT). The first method has been used in geotechnical engineering, but the second one has not been associated with geotechnics so far. Both methods are applied to a case study in which the parameters of changes are estimated. The knowledge of the variability of parameters allows in a long term more effective estimation, for example, bearing capacity probability of failure.
Źródło:
Studia Geotechnica et Mechanica; 2015, 37, 4; 95-103
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatial and temporal variability of sea surface temperature in the Baltic Sea based on 32-years (1982–2013) of satellite data
Autorzy:
Stramska, M.
Bialogrodzka, J.
Powiązania:
https://bibliotekanauki.pl/articles/48273.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
satellite data
sea surface temperature
Baltic Sea
annual cycle
climate change
spatial variability
temporal variability
Źródło:
Oceanologia; 2015, 57, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The impact of tides and waves on near-surface suspended sediment concentrations in the English Channel
Autorzy:
Guillou, N.
Rivier, A.
Chapalain, G.
Gohin, F.
Powiązania:
https://bibliotekanauki.pl/articles/48548.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
suspended sediment concentration
spatial variability
temporal variability
coastal water
English Channel
bathymetry
numerical modelling
ROMS model
MERIS data
Opis:
Numerous ecological problems of continental shelf ecosystems require a refined knowledge of the evolution of suspended sediment concentrations (SSC). The present investigation focuses on the spatial and temporal variabilities of near-surface SSC in coastal waters of the English Channel (western Europe) by exploiting numerical predictions from the Regional Ocean Modeling System ROMS. Extending previous investigations of ROMS performances in the Channel, this analysis refines, with increased spatial and temporal resolutions, the characterization of near-surface SSC patterns revealing areas where concentrations are highly correlated with evolutions of tides and waves. Significant tidal modulations of near-surface concentrations are thus found in the eastern English Channel and the French Dover Strait while a pronounced influence of waves is exhibited in the Channel Islands Gulf. Coastal waters present furthermore strong SSC temporal variations, particularly noticeable during storm events of autumn and winter, with maximum near-surface concentrations exceeding 40 mg l1 and increase by a factor from 10 to 18 in comparison with time-averaged concentrations. This temporal variability strongly depends on the granulometric distribution of suspended sediments characterized by local bimodal contributions of silts and sands off coastal irregularities of the Isle of Wight, the Cotentin Peninsula and the southern Dover Strait.
Źródło:
Oceanologia; 2017, 59, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatial variability and efficiency of treatment mean comparisons in an experiment with fodder pea using modern statistical methods.
Autorzy:
Gołaszewski, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/2198840.pdf
Data publikacji:
2001-06-21
Wydawca:
Instytut Hodowli i Aklimatyzacji Roślin
Tematy:
spatial variability
ANOVA
ANCOVA
NNA
kriging
relative efficiency
Opis:
It is typical of breeding experimentation to conduct experiments on large breeding material tested on small plots with a limited number of replications. Under such conditions, observations made on adjacent plots are biased by the effect of autocorrelation and fertility trends. The actual treatment effects can be masked and the capability of the breeder to detect true treatment differences is impaired. This paper deals with the problem of the estimation of effects of spatial variability and their impact on the efficiency of treatment comparisons. The considerations are based on the results from a breeding experiment with 25 treatments of fodder pea arranged according to the partially balanced incomplete block design (IBD) with 4 replications. Plant height and seed yield were analysed with the conventional statistical method ANOVA, the nearest neighbour analysis (NNA) and kriging. Eventually, the efficiency of the neoclassical methods relative to the completely randomised design (CRD) and randomised block design (RBD) was calculated. The estimation of the treatment effect on plant height was accomplished most efficiently with the NNA, whereas the efficiency of the alternative methods in the estimation of seed yield was comparable to the efficiency of the RBD.
Źródło:
Plant Breeding and Seed Science; 2001, 45, 1; 87-98
1429-3862
2083-599X
Pojawia się w:
Plant Breeding and Seed Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorptive properties of natural water surfactant films. Dead Vistula catchment water studies
Autorzy:
Pogorzelski, S.J.
Kogut, A.D.
Powiązania:
https://bibliotekanauki.pl/articles/48236.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
temporal variability
natural water
inland water
natural film
surface isotherm
scaling procedure
spatial variability
surfactant
adsorption kinetics
Vistula River
catchment area
Opis:
The paper contains the results of natural film experiments carried out on inland waters in the Dead Vistula (Martwa Wisła) catchment area during 1999–2002 using the integrated Langmuir trough-Wilhelmy plate system,w hich ‘cuts out’ an undisturbed film-covered area without any physicochemical sample processing. The static film parameters result from the generalized scaling procedures applied to the surface pressure-area isotherms. They appear to correspond well to observations of the film composition (Alim, MW, Eisoth),film solubility and the miscibility of its components (via R, ΔSc and y factors),and surface concentration (πeq, Γeq). A novel approach is presented for the adsorption dynamics on the basis of the mixed kinetic-diffusion model and analyses of the dynamic surface pressure plots,whic h leads to the determination of the effective relative diffusion coefficient Deff/D and activation energy barrier Ea/RT . There is reason to believe that certain classes of film-forming components or ‘end-members’ may dominate the static and dynamic surface properties. Some of these substances can be used as source-specific surface-active biomarkers to trace temporal and spatial changes due to environmental factors or the production of biological matter. The concept was tested for the Dead Vistula river and its tributaries. The results demonstrate that natural films are a complex mixture of biopolymeric molecules covering a wide range of solubilities,sur face activities and molecular masses with an apparent structural film architecture. Such studies could lead to the development of film structure parameters – indicators of ecosystem quality and the state of the environment.
Źródło:
Oceanologia; 2003, 45, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The analysis of spatial variability of precipitation in Poland in the multiyears 1981–2010
Autorzy:
Grzywna, Antoni
Bochniak, Andrzej
Ziernicka-Wojtaszek, Agnieszka
Krużel, Joanna
Jóźwiakowski, Krzysztof
Wałęga, Andrzej
Ciupak, Agnieszka
Mazur, Andrzej
Obroślak, Radomir
Serafin, Artur
Powiązania:
https://bibliotekanauki.pl/articles/292589.pdf
Data publikacji:
2020
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
climate change
kriging
Polska
precipitation
spatial variability
water resources
Opis:
The purpose of the paper is to analyze the spatial variability of precipitation in Poland in the years 1981–2010. The average annual rainfall was 607 mm. Precipitation in Poland is characterized by high spatial and temporal variability. The lowest annual precipitation was recorded in the central part of the country, where they equaled 500 mm. The highest annual precipitation totals were determined in the south, equaling 970 mm. The average precipitation in the summer half-year is 382 mm (63% of the annual total). On the basis of data from 53 climate stations, maps were made of the spatial distribution of precipitation for the period of the year and winter and summer half-year. The kriging method was used to map rainfall distribution in Poland. In the case study, cross-validation was used to compare the prediction performances of three periods. Kriging, with exponential type of semivariogram, gave the best performance in the statistical sense. Their application is justices especially in areas where landform is very complex. In accordance with the assumptions, the mean prediction error (ME), mean standardized prediction error (MSE), and root mean-square standardized prediction error (RMSSE) values are approximately zero, and root-mean-square prediction error (RMSE) and average standard error (ASE) reach values well below 100.
Źródło:
Journal of Water and Land Development; 2020, 46; 105-111
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Spatial Variability of Selected Soil Properties in the Hard Coal Post-Mining Area
Autorzy:
Klatka, Sławomir Tomasz
Malec, Magdalena
Ryczek, Marek
Powiązania:
https://bibliotekanauki.pl/articles/125377.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
spatial variability
soil properties
coal post-mining area
kriging
Opis:
The result of geomechanical and hydrological degradation caused by the underground extraction of hard coal are the transformations of the environmentally managed terrains and high variability of soil properties occurring in these areas. The analysis of selected soil properties of spatial variability in the post-mining area conducted by means of the kriging technique was presented in the paper. The determined points of empirical semivariogram were described by means of mathematical functions and theoretical semivariograms were plotted. The conducted analysis allowed to plot the maps of variability isolines, which my provide a basis to delineate the boundaries of areas most susceptible to the hydrological degradation of soils. The obtained research results indicate that the applied kriging technique may prove to be a useful tool for determining spatial variability of soils in the areas of hard coal mining operations and allow to delineate the boundaries of the areas most susceptible to soil degradation.
Źródło:
Journal of Ecological Engineering; 2019, 20, 3; 185-193
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena przestrzennej zmienności występowania opadów atmosferycznych w Centralnej Polsce w latach 2013-2015
Assessment of spatial and temporal variability of rainfall in Central Poland in the year 2013-2015
Autorzy:
Wójcik, K.
Treder, W.
Zbudniewek, A.
Powiązania:
https://bibliotekanauki.pl/articles/101053.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Infrastruktura i Ekologia Terenów Wiejskich PAN
Tematy:
deszcz
okres bezdeszczowy
zmienność przestrzenna
precipitation
rainless period
spatial variability
Opis:
W warunkach klimatycznych Polski opady atmosferyczne są podstawowym źródłem wody dla roślin. Klimat Polski określany jest jako przejściowy, zmienny i kontrastowy. Zmienny jest także rozkład opadów w czasie sezonu wegetacyjnego, w tej samej porze roku mogą występować wielodniowe okresy bezopadowe lub długotrwałe nadmierne opady. Opady charakteryzują się różną wielkością i intensywnością. Celem podjętych badań była analiza przestrzennej zmienności opadów atmosferycznych w centralnej Polsce. Dane pomiarowe obejmowały okresy wegetacyjne od IV do X w latach 2013-2015. Analiza wyników potwierdza opinię o bardzo dużej zmienności sum opadów, ich maksymalnych wysokości i intensywności oraz długości ciągów dni z opadem i bez opadów. Różnice wykazano na stacjach położonych nawet bardzo blisko siebie. Na podstawie przeprowadzonej analizy można stwierdzić, że opady powinny być mierzone bezpośrednio w miejscu, dla którego szacowany jest bilans wodny.
In Polish climatic conditions rainfall constitutes the main source of water for vegetation. The climate of Poland is characterized by high temporal and spatial variation. The total amount and seasonal distribution of precipitation show significant variability. The aim of the study was to analyze spatial changeability of rainfall in Central Poland. Data concerning rainfall were collected during the vegetative seasons of April - October in years 2013 - 2015. Analysis of the results confirms the observation which states that there is a great spatial variability of sum of precipitation, its maximum amount and intensity as well as the length of dry and rainy periods. Significant differences were observed between the stations located very close to each other. On the basis of obtained results it is stated that the rainfall must be measured directly on the area for which the water balance is to be estimated.
Źródło:
Infrastruktura i Ekologia Terenów Wiejskich; 2016, I/1; 73-87
1732-5587
Pojawia się w:
Infrastruktura i Ekologia Terenów Wiejskich
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatial variability study of rainfall in Cartagena de Indias, Colombia
Autorzy:
Mouthon-Bello, Javier A.
Quiñones-Bolaños, Edgar
Ortiz-Corrales, Jairo E.
Mouthon-Barraza, Natalia
Hernández-Fuentes, Maria D.J.
Caraballo-Meza, Andrea C.
Powiązania:
https://bibliotekanauki.pl/articles/2174346.pdf
Data publikacji:
2022
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
coastal city
rainfall duration
rainfall intensity
spatial correlation
spatial variability
Opis:
Precipitation is a component of the hydrological cycle, knowing its spatial distribution is vital for the management of hydrographic basins, the territory and the development of fundamental activities for society. That is why the present study shows the spatial variability of rainfall in Cartagena de Indias city with a network of rain gauges, made up of nine pieces of equipment, separated from each other by 0.9-27 km. After a year of recording (2019), using historical series of data, it was found that the maximum rainfall occurs in the trimester between September and November, with interpolated maps made by the Ordinary Kriging (OK) method it was found that the maximum rainfall is focused on the north, centre and west of the territory, instead, the maximum intensities are presented in the centre and west, the minimums for both variables are presented to the east and south. The 70 and 90% of the rain events have a duration of less than 30 min and 1 h, respectively. Three-parameter exponential function was fitted to the paired correlation distances, and presented correlations lower than 0.8, 0.5 and 0.2 from distances of 1, 3 and 7 km, respectively, in 30 min rain integration. It was also found that with a pluviometric network conformed by at least six pieces of equipment and separated by a 5 km distance from each other in the urban area, a correlation of 0.5 and compliance with the WMO recommendations would be obtained.
Źródło:
Journal of Water and Land Development; 2022, 55; 138--149
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł

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