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    Wyświetlanie 1-21 z 21
    Tytuł:
    Impact of Microphytobenthos Photosynthesis on the Characteristics of the Echo Signal from Baltic Sandy Sediments
    Autorzy:
    Gorska, N.
    Kowalska-Duda, E.
    Marszal, J.
    Schmidt, J.
    Klusek, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/177331.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    hydroacoustics
    backscattering
    microphytobenthos photosynthesis
    Baltic Sea
    Opis:
    The understanding the influence of biological processes on the characteristics of the signals backscattered by the sea floor is crucial in the development of the hydroacoustical benthic habitat classification techniques. The impact of the microphytobenthos photosynthesis on the acoustical backscattering properties of the Atlantic sandy sediments was previously demonstrated by Holliday et al. (2004) and Wildman and Huettel (2012). To account for the sensitivity of the hydroacoustical classification techniques to the backscattering properties of local marine sediments, it is important to understand the microphytobenthos photosynthesis impact for the Baltic Sea where the techniques are being actively developed now. This is the main motivation of the paper. In the paper the influence of the microphytobenthos photosynthesis on the characteristics of the echo signals reflected by sandy sediments in the typical Baltic temperature and the salinity conditions is discussed. The interdisciplinary multiday laboratory experiment was conducted to study the impact of benthic microalgal photosynthesis on the characteristics of the echo signal reflected by sandy sediments. Hydroacoustical data were collected under controlled constant light, temperature and salinity conditions. The oxygen content at different levels of the water column was simultaneously monitored.
    Źródło:
    Archives of Acoustics; 2015, 40, 3; 395-405
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of microphytobenthos photosynthesis on the spectral characteristics of the signal reflected from Baltic sandy sediments
    Autorzy:
    Jaśniewicz, D.
    Gorska, N.
    Powiązania:
    https://bibliotekanauki.pl/articles/332045.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Tematy:
    hydroacoustics
    backscattering
    microphytobenthos photosynthesis
    Baltic Sea
    Opis:
    The use of hydracoustical techniques to classify benthic fauna and flora is one of the important challenges in present marine research. It is crucial to understand the microphytobenthos photosynthesis impact on the backscattering properties of the sea floor in the Baltic Sea, where the techniques are actively developed now. This motivated our study. The data used in the analysis was collected in the multiday laboratory experiment conducted in the frame of the grant of the National Science Centre, Poland (No. N306 773940). In this experiment, during changing light conditions (light/dark photocycles), the hydroacoustical backscattering data was acquired in the aquarium with a sandy bottom. The constant temperature and salinity conditions, typical for the Southern Baltic, were kept, and oxygen content was monitored. In this paper data collected at 280 kHz, was processed. It was studied how the energy of echo and power spectral density of the echo signal, are sensitive to the microphytobenthos photosynthesis.
    Źródło:
    Hydroacoustics; 2016, 19; 165-171
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An acoustic study of zooplankton diel vertical migration in the Black Sea
    Autorzy:
    Pezacki, P. D.
    Gorska, N.
    Soloviev, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/332185.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Tematy:
    hydroacoustics
    backscattering
    ADCP
    velocity of zooplankton
    Opis:
    Reliable, rapid and non-invasive techniques are important for the monitoring of the ecosystem of the semi-enclosed Black Sea, especially sensitive to the human impact. Hydroacoustic techniques meet these requirements. In the study, the ADCP data (volume backscattering strength and water velocities), collected in the north-east part of the Black Sea in October 2014, were used to understand some biotic and abiotic processes in the environment. The study was motivated by the fact that the used ADCP mounted on the autonomous (moving vertically) platform provided measurements with significantly higher spatial resolution that it was in the previous hydroacoustical studies of Black Sea ecosystem. The main objective of the analysis was to determine the velocity of zooplankton diel vertical migration and understand the processes responsible for the variability of the volume backscattering strength.
    Źródło:
    Hydroacoustics; 2017, 20; 139-148
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Temperature detection based on nonparametric statistics of ultrasound echoes
    Autorzy:
    Byra, M.
    Gambin, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/332315.pdf
    Data publikacji:
    2015
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Tematy:
    noninvasive temperature monitoring
    nonparametric statistics
    ultrasound backscattering
    Opis:
    Different ultrasound echoes properties have been used for the noninvasive temperature monitoring. Temperature variations that occur during heating/cooling process induce changes in a random process of ultrasound backscattering. It was already proved that the probability distribution of the backscattered RF (radio frequency) signals is sensitive to the temperature variations. Contrary to previously used methods which explored models of scattering and involved techniques of fitting histograms to a special probability distribution two more direct measures of changes in statistics are proposed in this paper as temperature markers. They measure the ''distance'' between the probability distributions. The markers are the Kolmogorov Smirnov distance and Kulback-Leiber divergence. The feasibility of using such nonparametric statistics for non- invasive ultrasound temperature estimation is demonstrated on the ultrasounds data collected during series of heating experiments in which the temperature was independently registered by the classical thermometer or thermocouples.
    Źródło:
    Hydroacoustics; 2015, 18; 17-23
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study of a Compton backscattering wall defects detection device using the Monte Carlo method
    Autorzy:
    Qin, Xuan
    Yang, Jianbo
    Du, Zhengcong
    Xu, Jie
    Li, Rui
    Li, Hui
    Liu, Qi
    Powiązania:
    https://bibliotekanauki.pl/articles/24202748.pdf
    Data publikacji:
    2023
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    compton backscattering
    Monte Carlo
    nondestructive testing
    wall defect
    Opis:
    In view of the shortcomings of traditional wall defect detection methods, such as small detection range, poor accuracy, non-portable device, and so on, a wall defects detection device based on Compton backscattering technology is designed by Monte Carlo method, which is mainly used to detect the size and location information of defects in concrete walls. It mainly consists of two parts, the source container and the detection system: first, through the simulation and analysis of the parameters such as the receiving angle of thebackscattered particles and the rear collimating material of the detector, the influence of the fluorescent X-ray peak of the detector collimating material on the backscattered particle counts is eliminated and the detected error is reduced; second, the ring array detector design, compared with single array detector and surface array detector, can facilitate real-time detection of defect orientation, expanding the single scan range and improving the detection efficiency. After simulation and comparative analysis, the relevant optimal parameters are obtained: the object is detected using a Cs-137 γ-ray source with an activity of 6 mCi, and a ring detector consisting of four 0.5-inch cube-shaped CsI scintillator detectors is placed at 150° to receive the backscattered photons. The simulation analysis using the Monte Carlo FLUKA program showed that the maximum depth of wall defect detection is 8 cm, the maximum error fl uctuation range of defect depth and thickness is ±1 cm, the overall device weight is <20 kg, and the measurement time is <5 min.
    Źródło:
    Nukleonika; 2023, 68, 2; 57--63
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Monte Carlo calculations of positron implantation profiles and backscattering probabilities in gold
    Autorzy:
    Aydin, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/147555.pdf
    Data publikacji:
    2001
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    backscattering
    computer simulation
    incoming angle
    mean penetration depth
    positron
    Opis:
    The transport of charged particles through matter is worth considering for various applications. In this work, backscattering probabilities and mean penetration depths were calculated from the implantation profiles for positrons of energies 1-75 keV entering normally at various angles into a semi-infinite gold target. The theoretical results of backscattering probability and mean penetration depth are compared with other published [1, 3, 4, 10, 11, 13]. Monte Carlo calculations and experimental results for the semi-infinite gold target. In general, good agreement is observed.
    Źródło:
    Nukleonika; 2001, 46, 3; 87-90
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Monte Carlo calculations of low energy positrons in silicon
    Autorzy:
    Aydin, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/148795.pdf
    Data publikacji:
    2005
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    Monte Carlo method
    positron transmission
    backscattering
    angular distribution
    energy distribution
    Opis:
    Theoretical data for positron scattering from a thin silicon film and semi-infinite silicon are presented as a function of incident and outgoing angles and energies. These theoretical data of the scattering processes of low energy positrons penetrating into silicon were performed by Monte Carlo simulation. The simulation is based on the use of different types of differential cross sections for individual elastic and inelastic scattering i) inelastic scattering; Gryzinski's excitation function to simulate the energy loss and Liljequist's model to calculate the inelastic scattering cross section, ii) elastic scattering; the screened Rutherford differential cross section with the spin-relativistic factor. In calculations on positron traversing matter, it is important to know the transmission through medium, their path lengths, and their energy and angular distribution through matter. The simulation results are well agreed with experiments.
    Źródło:
    Nukleonika; 2005, 50, 1; 37-42
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Ultrasonic Simulation Research of Two-Dimensional Distribution in Gas-Solid Two-Phase Flow by Backscattering Method
    Autorzy:
    Fan, Jinhui
    Wang, Fei
    Powiązania:
    https://bibliotekanauki.pl/articles/31339986.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    gas-solid two-phase flow
    COMSOL simulation
    ultrasonic backscattering method
    Opis:
    The two-dimensional distribution of gas-solid flow parameters is a great research significance to reflect the actual situation in industry. The commonly used method is the ultrasonic tomography method, in which multiple probes are arranged at various angles, or the measurement device is rotated as that in medicine, but in most industrial situations, it is impossible to install probes at all angles or rotate the measured pipe. The backscattering method, however, uses only one transducer to both transmit and receive signals, and the two-dimensional information is obtained by only rotating the transducer. Ultrasound attenuates greatly in the air, and the attenuation changes with frequency. Therefore, Comsol is used to study the reflection of particles with different radii in the air to ultrasound with various frequencies. It is found that the backscattering equivalent voltage is the largest when the product of ultrasonic frequency and particle radius is about 27.78 Hz·m, and the particle concentration of 30% causes the strongest backscattering. The simulated results are in good agreement with the Faran backscattering model, which can provide references for selecting the appropriate frequency and obtaining the concentration when measuring gas-solid two-phase flow with the ultrasonic backscattering method.
    Źródło:
    Archives of Acoustics; 2022, 47, 3; 373-382
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Parameterization of light scattering for solving the inverse problem of determining the concentrations of the principal light scattering and absorbing admixtures in shelf waters
    Autorzy:
    Pelevin, V.N.
    Rostovtseva, V.V.
    Powiązania:
    https://bibliotekanauki.pl/articles/48226.pdf
    Data publikacji:
    2001
    Wydawca:
    Polska Akademia Nauk. Instytut Oceanologii PAN
    Tematy:
    bio-optical modelling
    backscattering
    sea water
    shelf water
    light absorption
    irradiance
    Opis:
    A method for estimating the water backscattering coefficient was put forward on the basis of experimental data of diffuse attenuation coefficient for downwelling irradiance and irradiance reflectance. Calculations were carried out for open sea waters of different types and the spectral dependencies were found (‘anomalous’ spectra) and explained. On this basis, a new model of light backscattering on particles in the sea is proposed. This model may be useful for modelling remote sensing reflectance spectra in order to solve the inverse problems of estimating the concentration of natural admixtures in shelf waters.
    Źródło:
    Oceanologia; 2001, 43, 4
    0078-3234
    Pojawia się w:
    Oceanologia
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Monte Carlo simulation of polarization of light back-scattered from randomly rough surfaces
    Autorzy:
    Jiang, Yuxiang
    Li, Zhenhua
    Powiązania:
    https://bibliotekanauki.pl/articles/2202767.pdf
    Data publikacji:
    2023
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    backscattering
    randomly rough surface
    Stokes parameters
    Monte Carlo method
    polarized light
    Opis:
    Laser detection devices obtain target information from back-scattered light, such as lidar. The recognition rate can be improved by analyzing intensity and polarization of echo signal. In this paper, Monte Carlo method is used to generate a large number of randomly rough surfaces to simulate targets. Every rough surface is discretized into a large number of micro-surface elements. Stokes parameters of back-scattered light are calculated by numerical integration. Incident light is p-, s-, 45° linearly polarized light and right-hand circularly polarized light, respectively. Numerical results show that when s- and p-linearly polarized light incident on a metal rough surface, back-scattered light appears circularly polarized component. Metal rough surface resembles a wave plate with phase difference, with the fast axis parallel or perpendicular to the 45° direction. When linearly polarized light is incident on dielectric rough surface, back-scattered light has no circularly polarized component. Experimental data are consistent with the numerical results. The above research provides a new basis for laser detection device to identify metal targets from the environmental background.
    Źródło:
    Optica Applicata; 2023, 53, 1; 65--85
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Brillouin backscattering analysis in recent generation of telecom optical fibers
    Autorzy:
    Lakomski, Mateusz
    Tosik, Grzegorz
    Powiązania:
    https://bibliotekanauki.pl/articles/2172828.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    Brillouin backscattering
    optical fibre
    optical fibre application
    optical fibre sensor
    strain measurement
    Opis:
    This paper reports on examination of the latest generation of telecom optical fibers for the Brillouin backscattering strain sensor application. Over 30 fibers from 5 different manufactures have been tested in terms of their ability to create a stable and accurate strain sensor. It has been proved that fibers that belong to the same standard, according to ITU-T (International Telecommunication Union), and even if provided by one manufacturer, demonstrate fundamentally different Brillouin backscattering response. It has been shown that unimodal Brillouin spectrum cannot be treated as the main parameter for fiber selection. In order to achieve accurate and reproducible results of strain measurement, it is necessary to perform initial examination of the fibers over the range of laser pulse width.
    Źródło:
    Optica Applicata; 2022, 52, 3; 405--416
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Post-acceleration of ions from the laser-generated plasma
    Autorzy:
    Giuffrida, L.
    Torrisi, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/146664.pdf
    Data publikacji:
    2011
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    laser ablation
    laser-plasma
    post-acceleration
    ion implantation
    Rutherford backscattering spectrometry (RBS) analysis
    Opis:
    An application of the laser-generated plasma for multi-energetic ion implantation is reported. In an experiment performed at Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud (INFN-LNS) of Catania, Italy the Nd:YAG laser was used, operating at the 1064 nm wavelength with the intensity of 1010 W/cm2. A laser pulse of 9 ns duration and 300 mJ energy was employed to ablate a solid target placed in a high vacuum. The free ion expansion occurred in a constant potential chamber placed at 30 kV positive voltage with respect to the ground, which allowed to extract ions with energy proportional to the charge state. In an another experiment, performed at the PALS Prague laser facility (1315 nm, 400 ps pulse width and the laser pulse energy delivered on target equal to about 35 J) Ti ions were obtained through the ablation of solid targets in vacuum by means of 1015 W/cm2 laser pulses. In both cases ion energy analyzers were used to measure the energy-to-charge ratio of the ions. The ion energy distribution was determined from the time-of-flight measurements. The depth profiles measured through Rutherford backscattering spectrometry (RBS) analysis are in good agreement with the ion energy analyzer spectroscopy measurements.
    Źródło:
    Nukleonika; 2011, 56, 2; 161-163
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthesis and Characterization of Co-Cs-Nd-Sr-Doped Perovskite-Rutile-Type Structure
    Autorzy:
    Smolinski, T.
    Zhao, L.
    Rogowski, M.
    Wawszczak, D.
    Olczak, T.
    Brykala, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/355628.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Synroc
    X-ray diffraction
    Rutherford backscattering
    particle induced X-ray emission
    Roentgen computed microtomography
    Opis:
    The perovskite type matrix is considered as solidification material for high-level radioactive waste. In this work the perovskite-rutile-type matrix doped by Co, Cs, Nd and Sr which simulate nuclear waste was prepared by sol-gel route. The material was characterized by several methods such as: X-ray diffraction, energy dispersive X-ray spectrometer, and particle induced X-ray emission combined with Rutherford backscattering spectrometry. The analyzes confirmed chemical composition Co-Cs-Nd-Sr-doped perovskite-rutile-type structure. A virtual model of the pellet`s structure was created non-destructively by Roentgen computed micro-tomography. The leaching tests confirmed high chemical resistance of the matrix.
    Źródło:
    Archives of Metallurgy and Materials; 2020, 65, 4; 1417-1423
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Spectral dependence of the correlation between the backscattering coefficient and the volume scattering function measured in the Southern Baltic Sea
    Autorzy:
    Freda, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/47893.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Instytut Oceanologii PAN
    Tematy:
    volume scattering function
    backscattering coefficient
    marine optics
    Baltic Sea
    optical property
    sea water
    spectral variability
    Opis:
    Direct measurements of the backscattering coefficient bb require the determination of the Volume Scattering Function (VSF) and its integration over a backward hemisphere. In sea water they are difficult and are therefore carried out very rarely. That is why the backscattering coefficient is much more frequently obtained with so-called single angle scattering meters: these operate by measuring the VSF for a fixed angle region of the backward hemisphere. This article examines the spectral variability of the correlation between directly measured backscattering coefficients and VSFs. Also presented are the averaged slopes of VSF spectra, measured in southern Baltic waters over a wide range of scattering angles.
    Źródło:
    Oceanologia; 2012, 54, 3
    0078-3234
    Pojawia się w:
    Oceanologia
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Crystal Lattice Damage and Recovery of Rare-Earth implanted Wide Bandgap Oxides
    Autorzy:
    Sarwar, Mahwish
    Ratajczak, Renata
    Ivanov, Vitalii
    Mishra, Sushma
    Turek, Marcin
    Wierzbicka, Aleksandra
    Woźniak, Wojciech
    Guziewicz, Elżbieta
    Powiązania:
    https://bibliotekanauki.pl/articles/2204945.pdf
    Data publikacji:
    2022
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    wide bandgap oxides
    zinc oxide
    gallium oxide
    rare earth
    ion implantation
    Rutherford backscattering spectrometry
    low temperature photoluminescence
    Opis:
    Rare earth (RE) elements are important for the optical tuning of wide bandgap oxides (WBO) such as β-Ga2O3 or ZnO, because β-Ga2O3:RE or ZnO:RE show narrow emission lines in the visible, ultra-violet and infra-red region. Ion implantation is an attractive method to introduce dopant into the crystal lattice with an extraordinary control of the dopant ion composition and location, but it creates the lattice damage, which may render the dopant optically inactive. In this research work, we investigate the post-implantation crystal lattice damage of two matrices of wide-bandgap oxides, β-Ga2O3 and ZnO, implanted with rare-earth (RE) to a fluence of 5 x 10^14, 1 x 10^15 and 3 x 10^15 atoms/cm^2, and post-growth annealed in Ar and O2 atmosphere, respectively. The effect of implantation and annealing on both crystal lattices was investigated by channeling Rutherford backscattering spectrometry (RBS/C) technique. The level of crystal lattice damage caused by implantation with the same RE fluences in the case of β-Ga2O3 seems to be higher than in the case of ZnO. Low temperature photoluminescence was used to investigate the optical activation of RE in both matrices after performed annealing.
    Źródło:
    Advances in Science and Technology. Research Journal; 2022, 16, 5; 147--154
    2299-8624
    Pojawia się w:
    Advances in Science and Technology. Research Journal
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Simple statistical formulas for estimating biogeochemical properties of suspended particulate matter in the Southern Baltic Sea potentially useful for optical remote sensing applications
    Autorzy:
    Wozniak, S.B.
    Powiązania:
    https://bibliotekanauki.pl/articles/47701.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Instytut Oceanologii PAN
    Tematy:
    biogeochemical property
    suspended particulate matter
    particulate organic carbon
    inherent optical property
    chlorophyll a
    light absorption
    backscattering coefficient
    remote sensing
    Baltic Sea
    Źródło:
    Oceanologia; 2014, 56, 1
    0078-3234
    Pojawia się w:
    Oceanologia
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A comparison of ASCAT wind measurements and the HIRLAM model over the Baltic Sea
    Autorzy:
    Sluzenikina, J.
    Mannik, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/48369.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Instytut Oceanologii PAN
    Tematy:
    backscattering
    Baltic Sea
    HIRLAM model
    numerical weather prediction
    ocean surface
    sea surface
    stormy season
    wind direction
    wind field
    wind scatterometer
    wind speed
    Opis:
    This paper presents a comparison of the wind data measured by the ASCAT polar-orbiting satellite scatterometer and winds forecast by the numerical weather prediction model HIRLAM in the Baltic Sea region during the stormy season in 2009. Two different resolution models were used in the comparison. Mutual quality and uncertainty characteristics of the measurements and predictions are determined. The results of the study show that the ASCAT wind data are well correlated with the HIRLAM predicted winds, which raises the credibility of both data sources in operational and hindcasting applications over the Baltic Sea. A case of phase error in a HIRLAM forecast of cyclonic activity over the Baltic Sea is discussed.
    Źródło:
    Oceanologia; 2011, 53, (1-TI)
    0078-3234
    Pojawia się w:
    Oceanologia
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Revisiting the role of oceanic phase function in remote sensing reflectance
    Autorzy:
    Freda, W.
    Piskozub, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/48003.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Instytut Oceanologii PAN
    Tematy:
    marine optics
    remote sensing
    scattering
    backscattering
    volume scattering function
    angular variation
    scattering light intensity
    inherent optical property
    sea surface
    solar radiation
    angular distribution
    Opis:
    The effect of angular structure differences between measured and best-fit analytical phase functions of the equivalent backscattering ratio on calculated reflectance values was studied and shown to be significant. We used a Monte Carlo radiative transfer code to check the effect of choosing different analytical (several Fournier- Forand (1994) and Henyey-Greenstein (1941)) phase functions with backscattering ratios identical to the ‘classical’ average Petzold function. We show that the additional variability of the resulting water leaving radiance is about 7% (4% between the Fournier-Forand functions themselves) for most scenarios. We also show a previously unknown maximum of the discrepancy (up to 10%) for highly scattering waters. We discuss the importance of relative differences in phase function for different angular ranges to this maximum and to the behaviour of the discrepancy as a function of solar zenith angle.
    Źródło:
    Oceanologia; 2012, 54, 1
    0078-3234
    Pojawia się w:
    Oceanologia
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wpływ parametrów fizycznych aerozoli na efektywny współczynnik odbicia wstecznego
    Influence of aerosol physical characteristics on backscattering coefficient
    Autorzy:
    Wojtanowski, J.
    Mierczyk, Z.
    Zygmunt, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/208490.pdf
    Data publikacji:
    2009
    Wydawca:
    Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
    Tematy:
    rozpraszanie
    współczynnik odbicia
    teoria Mie
    zdalne wykrywanie aerozoli
    LIDAR
    teledetekcja laserowa
    aerozol
    scattering
    backscattering coefficient
    Mie theory
    remote sensing of aerosols
    lidar
    laser remote sensing
    aerosol
    Opis:
    W artykule przeprowadzono wielopłaszczyznową analizę wpływu poszczególnych parametrów fizycznych na wartość współczynnika wstecznego odbicia od aerozolu. W technikach teledetekcji laserowej, współczynnik ten jest kluczową wielkością charakteryzującą analizowany aerozol. Umiejętność jego wyznaczania dla promieniowania o dowolnej długości fali, na podstawie znajomości zespolonego współczynnika załamania oraz rozkładu wielkości cząstek tworzących dany aerozol stwarza więc możliwości w zakresie jego identyfikacji (odwrotne zagadnienie lidarowe). Zasadniczym celem pracy jest wielospektralna analiza parametrów rozproszeniowych aerozoli wynikających z teorii Mie oraz wyznaczenie charakterystyk zasięgowych systemu lidarowego do zdalnego wykrywania i identyfikacji skażeń chemicznych i biologicznych.
    A wide analysis of the main aerosol physical parameters' impact on the backscattering coefficient has been developed. In the remote-sensing techniques, its value is considered to be one of the most crucial factors, since it corresponds to the properties of the remotely sensed aerosol. The capability of determining it theoretically, basing on the value of complex refractive index and the size distribution function of particles, creates the fundamental tool for identifying the unknown aerosol (inverse lidar problem). A computational code has been developed at the MATLAB environment. The calculations presented in the paper have been performed in accordance with Mie scattering theory.
    Źródło:
    Biuletyn Wojskowej Akademii Technicznej; 2009, 58, 1; 123-139
    1234-5865
    Pojawia się w:
    Biuletyn Wojskowej Akademii Technicznej
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Bio-optical trends of seas around Turkey: An assessment of the spatial and temporal variability
    Autorzy:
    Bengil, F.
    Mavruk, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/48746.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Instytut Oceanologii PAN
    Tematy:
    chlorophyll a
    coloured dissolved organic matter
    optical property
    backscattering coefficient
    marine ecosystem
    spatial variability
    temporal variability
    bio-optical property
    Aegean Sea
    Marmara Sea
    Black Sea
    Turkey
    Źródło:
    Oceanologia; 2018, 60, 4
    0078-3234
    Pojawia się w:
    Oceanologia
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modelowanie wymiany netto ekosystemu (NEE) na obszarach bagiennych z zastosowaniem danych satelitarnych
    Modeling of net ecosystem exchange (nee) at wetlands applying remote sensing
    Autorzy:
    Dąbrowska-Zielińska, K.
    Budzyńska, M.
    Tomaszewska, M.
    Malińska, A.
    Bartold, M.
    Gatkowska, M.
    Turlej, K.
    Małek, I.
    Turbiak, J.
    Jaszczyński, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/338335.pdf
    Data publikacji:
    2017
    Wydawca:
    Instytut Technologiczno-Przyrodniczy
    Tematy:
    ENVISAT ASAR
    Landsat 8 OLI
    NEE
    Sentinel-1A
    TerraSAR-X
    wilgotność gleby
    współczynnik wstecznego rozpraszania
    zawartość wody w roślinach
    backscattering coefficient
    soil moisture
    vegetation water content
    Opis:
    W artykule przedstawiono wyniki badań nad modelowaniem wymiany netto ekosystemu (NEE – ang. Net Ecosystem Exchange) bagiennego na przykładzie doliny Biebrzy z wykorzystaniem zdjęć satelitarnych i danych z pomiarów naziemnych z lat 2011–2015. Przeprowadzono szczegółową analizę zastosowania zdjęć optycznych i radarowych do uzyskania charakterystyk roślinno-wilgotnościowych wpływających na wymianę węgla. W wyniku przeprowadzonych analiz opracowano modele szacowania NEE, w których zastosowano opracowane na podstawie danych satelitarnych następujące parametry: wilgotność gleby (WG), zawartość wody w roślinach (WR). Do analizy WG i WR został zastosowany współczynnik wstecznego rozpraszania (σº) obliczony z sygnału zarejestrowanego w zakresie mikrofalowym przez urządzenia SAR (ang. Synthetic Aperture Radar) dla różnych polaryzacji fal. Prace badawcze zmierzające do określenia wielkości wymiany węgla oraz jego zróżnicowania przestrzennego i czasowego, przeprowadzone z uwzględnieniem informacji o pokrywie roślinnej i wilgotności gleby uzyskanych z danych satelitarnych, są ważne dla monitorowania ekosystemów bagiennych.
    The article presents results of the study on modeling Net Ecosystem Exchange (NEE) in the wetland ecosystem using remote sensing and in-situ data. The study has been conducted in Biebrza Valley for the years 2011–2015. The analysis of application of optical and microwave images for the assessment of vegetation-moisture conditions influenced carbon exchange has been performed. The impact of soil moisture and type of vegetation habitat on CO2 flux in wetland ecosystems has been analyzed to develop NEE models. Soil moisture (WG) and vegetation water content (WR) have been correlated with backscattering coefficient (σº) calculated from the signal registered by microwave satellites in different wave polarization. The research was focused on the assessment of carbon balance in time and space taking into account vegetation cover and soil moisture derived from satellite data. The research is important for monitoring wetland ecosystem.
    Źródło:
    Woda-Środowisko-Obszary Wiejskie; 2017, 17, 1; 31-51
    1642-8145
    Pojawia się w:
    Woda-Środowisko-Obszary Wiejskie
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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