• Airborne Investigation of Quasi-Specular Ku-Band Radar Scattering for Satellite Altimetry Over Snow-Covered Arctic Sea Ice 

      de Rijke Thomas, Claude; Landy, Jack Christopher; Mallett, Robbie; Willatt, Rosemary; Tsamados, Michel; King, Joshua (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-22)
      Surface-based Ku-band radar altimetry investigations indicate that the radar signal is typically backscattered from well above the snow–sea ice interface. However, this would induce a bias in satellite altimeter sea ice thickness retrievals not reflected by buoy validation. Our study presents a mechanism to potentially explain this paradox: probabilistic quasi-specular radar scattering from the ...
    • The airglow layer emission altitude cannot be determined unambiguously from temperature comparison with lidars 

      Dunker, Tim (Journal article; Peer reviewed; Tidsskriftartikkel, 2018)
      I investigate the nightly mean emission height and width of the OH*(3–1) layer by comparing nightly mean temperatures measured by the ground-based spectrometer GRIPS 9 and the Na lidar at ALOMAR. The data set contains 42 coincident measurements taken between November 2010 and February 2014, when GRIPS 9 was in operation at the ALOMAR observatory (69.3° N, 16.0° E) in northern Norway. To closely ...
    • Aktive antenner for ultrabredbånd-radar til deteksjon av brystkreft 

      Ryeng, Kristoffer (Master thesis; Mastergradsoppgave, 2008-10-01)
      Motivasjonen for denne oppgaven er en aktiv, smertefri og ufarlig metode for deteksjon av brystkreft ved bruk av ultrabredbånd mikrobølgeradar. Montering av lavstøyforsterker direkte etter mottakerantennen har en positiv effekt på signal-til-støyforholdet i radar-systemet, og en vesentlig del av oppgaven er å måle lavstøyforsterkeren gir. Grunnleggende teori om mikrobølger, antenner, forsterkere, ...
    • Algal hot spots in a changing Arctic Ocean: Sea-ice ridges and the snow-ice interface 

      Fernández-Méndez, Mar; Olsen, Lasse Mork; Kauko, Hanna M.; Meyer, Amelie; Rösel, Anja; Merkouriadi, Ioanna; Mundy, Christopher John; Ehn, Jens K.; Johansson, Malin; Wagner, Penelope Mae; Ervik, Åse; Sorrell, BK; Duarte, Pedro; Wold, Anette; Hop, Haakon; Assmy, Phillipp (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-12)
      During the N-ICE2015 drift expedition north-west of Svalbard, we observed the establishment and development of algal communities in first-year ice (FYI) ridges and at the snow-ice interface. Despite some indications of being hot spots for biological activity, ridges are under-studied largely because they are complex structures that are difficult to sample. Snow infiltration communities can grow at ...
    • Alignment of Multifrequency SAR Images Acquired over Sea Ice Using Drift Compensation 

      Demchev, Denis; Eriksson, Leif E.B.; Hildeman, Anders; Dierking, Wolfgang Fritz Otto (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-07)
      In this article, we investigate the feasibility to align synthetic aperture radar (SAR) imagery based on a compensation for sea ice drift occurring between temporally shifted image acquisitions. The image alignment is a requirement for improving sea ice classification by combining multifrequency SAR images acquired at different times. Images obtained at different radar frequencies provide ...
    • An alternative approach for calculating the SAR damping ratio of verified oil slicks 

      Quigley, Cornelius Patrick; Johansson, Malin; Jones, Cathleen Elaine (Journal article; Tidsskriftartikkel; Peer reviewed, 2022)
      The damping ratio is a calculated feature that measures the contrast between oil-slicked water and the open ocean in SAR data. To implement the damping ratio, the current literature suggests estimating the open water backscatter by taking strips of undefined width across the range direction, obtaining the damping ratio as a function of incidence angle. We show in this paper that the method proposed ...
    • The altitude of green OI 557.7 nm and blue N2+ 427.8 nm aurora 

      Whiter, Daniel K.; Partamies, Noora; Gustavsson, Bjorn Johan; Kauristie, Kirsti (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-01-06)
      We have performed a large statistical study of the peak emission altitude of green O(1D2–1S0) (557.7 nm) and blue 1 N (427.8 nm) aurora using observations from a network of all-sky cameras stationed across northern Finland and Sweden recorded during seven winter seasons from 2000 to 2007. Both emissions were found to typically peak at about 114 km. The distribution of blue peak altitudes is more ...
    • Amplitude and size scaling for interchange motions of plasma filaments 

      Kube, Ralph; Wiesenberger, Matthias; Garcia, Odd Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-07)
      The interchange dynamics and velocity scaling of blob-like plasma filaments are investigated using a two-field reduced fluid model. For incompressible flows due to buoyancy, the maximum velocity is proportional to the square root of the relative amplitude and the square root of its cross-field size. For compressible flows in a non-uniform magnetic field, this square root scaling only holds ...
    • Analyse av energibruk og teknisk drift ved Bryne videregående skole 

      Tjøtta, Louise Mitchell (Master thesis; Mastergradsoppgave, 2019-12-15)
      Tidligere Bryne videregående skole (vgs.) og Time vgs. ble i 2015 slått sammen til nye Bryne vgs. I den anledning ble det bygget tre nye skolebygg med et moderne og komplekst energisystem. Skolen er et pilotprosjekt i tråd med Rogaland fylkeskommune sin miljøpolitikk og er bygget med fokus på bærekraftige prinsipper, lavt energiforbruk og bruk av energikilder med begrenset CO2 utslipp. Skolens varme ...
    • Analysis of Correlations between Energy Consumption, Structural Specifications and Climate-Induced Variables to increase Energy Efficiency in Households and Buildings through a Prediction Model 

      Rasmussen, Christoffer Stene (Master thesis; Mastergradsoppgave, 2021-05-31)
      In a world where the transition towards increasingly progressive renewable energy sources is of great importance moving towards sustainability for our planet and future generations, a large portion of mundane equipment and machinery will turn to the usage of electricity rather than fossil fuel as a resource. This does however pose some challenges to the infrastructure in place as it increases the ...
    • Analysis of Deep Convolutional Neural Networks Using Tensor Kernels and Matrix-Based Entropy 

      Wickstrøm, Kristoffer; Løkse, Sigurd Eivindson; Kampffmeyer, Michael; Yu, Shujian; Príncipe, José C.; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-03)
      The aquaculture industry is expanding to meet the daily requirements of humanity from high-quality seafood. In this regard, intensive aquaculture systems are suggested, resulting in high production but being challenged with immunosuppression and disease invaders. Antibiotics were used for a long time to protect and treat aquatic animals; however, continuous use led to severe food safety issues, ...
    • Analysis of Deep Convolutional Neural Networks Using Tensor Kernels and Matrix-Based Entropy 

      Wickstrøm, Kristoffer Knutsen; Løkse, Sigurd Eivindson; Kampffmeyer, Michael Christian; Yu, Shujian; Príncipe, José C.; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-03)
      Analyzing deep neural networks (DNNs) via information plane (IP) theory has gained tremendous attention recently to gain insight into, among others, DNNs’ generalization ability. However, it is by no means obvious how to estimate the mutual information (MI) between each hidden layer and the input/desired output to construct the IP. For instance, hidden layers with many neurons require MI estimators ...
    • Analysis of dust impacts observed with the Radio Plasma Wave instrument onboard ESA’s Solar Orbiter 

      Ferkic, Alen (Master thesis; Mastergradsoppgave, 2023-12-15)
      Dust particles are one of the major constituents of the interplanetary medium in our solar system. They are presumably formed by fragmentation processes of meteoroids and for a certain range of sizes and parameters the dust particles move radially outwards from the Sun. The Radio plasma Wave (RPW) instrument on Solar Orbiter can measure dust particles that impact the spacecraft. By measuring the ...
    • Analysis of evolving oil spills in full-polarimetric and hybrid-polarity SAR 

      Espeseth, Martine Mostervik; Skrunes, Stine; Jones, Cathleen Elaine; Brekke, Camilla; Holt, Benjamin; Doulgeris, Anthony Paul (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-25)
      Oil spill detection using a time series of images acquired off Norway in June 2015 with the uninhabited aerial vehicle synthetic aperture radar is examined. The relative performance of a set of features derived from quad-polarization versus hybrid-polarity (HP) modes in detection of various types of slicks as they evolve on a high wind driven sea surface is evaluated. It is shown that the HP mode ...
    • Analysis of the dynamical behavior of the Minidusty rocket payloads, and its influence on the plasma probe measurements 

      Nácher Rodríguez, María (Master thesis; Mastergradsoppgave, 2007-06-25)
      In the present master thesis the dynamical behavior of the Mini-Dusty rockets will be analyzed with the aim to obtain accurate information on the absolute coning and orientation history during the flight, and in particular around all the critical phases.
    • Analysis of the potential of the Ku-band Gamma Portable Radar Interferometer for sea ice information extraction. 

      Asbjørnslett, Andreas Hansen (Master thesis; Mastergradsoppgave, 2020-06-29)
      Radar remote sensing is a key technology for monitoring sea ice. In this regard, passive microwave and Synthetic Aperture Radars (SARs) are the most important sensor types. This technology has been used for sea ice applications for four decades, but there are still many uncertainties related to sea ice monitoring by SAR. Some of these may be solved by multi-sensor observations, in which case other ...
    • Analysis of time series of polarimetric sea ice signatures observed in fast ice it the Belgica Bank area 

      Eltoft, Torbjørn; Johansson, Malin; Lohse, Johannes; Ferro-Famil, Laurent (Journal article; Tidsskriftartikkel, 2023-10-20)
      The CIRFA-Cruise 2022 with <i>RV Kronprins Haakon</i> to the north-eastern coast of Greenland in the period April 22nd to May 9th 2022 was organised to perform measurements and make observations which allow for validation of sea ice remote sensing information and forecast products resulting from work in the Centre for Integrated Remote Sensing and Forecasting for Arctic Operations(CIRFA), a Centre ...
    • Analyzing Behavioral Biometrics of Handwriting Using Myo Gesture Control Armband 

      Tveit, Brynjulv (Master thesis; Mastergradsoppgave, 2018-06-05)
      Through the last few decades, computer technology has gradually merged into our everyday lives. Computers and sensors are embedded in an increasing amount of household items, enabling us to monitor and remotely control our connected devices from apps on our smartphones. The technology interfaces are also evolving along with new technologies. Among the up and coming digital interfaces are wearable ...
    • Analyzing the Impact of Peak-Shaving on Load Reduction and on Battery Energy Storage System Degradation: A Simulation-Based Study in Husøy 

      Kournoutis, Georgios (Mastergradsoppgave; Master thesis, 2023-11-14)
      The island of Husøy, in Northern Senja, Norway, faces numerous voltage quality difficulties, which arise from the consequent surge in electricity demand by the local growing fishing industry. Collaborating with the local distribution system operator (DSO), Arva, the current study explores the implementation of Battery Energy Storage Systems (BESS) using a peak-shaving strategy to alleviate high-demand ...
    • Angle Dependent Reflectance and Performance of Solar Cells and Absorbers 

      Jordheim, Øystein (Master thesis; Mastergradsoppgave, 2018-05-14)
      In this thesis, the reflectance was measured for angles from 10 deg to 80 deg for different n-type silicon based solar cells and for solar absorbers. The measurements were done with unpolarized, p polarized and s polarized light. The reflectance results show that both the solar cells and solar absorbers perform well under small variation from perpendicular angle well but as the angle of incidence ...