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Resolution enhanced sea ice concentration: a new algorithm applied to AMSR2 microwave radiometry data
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-30)Passive-microwave sea ice concentration (SIC) algorithms employ different frequencies and polarisations in their operational implementations. Commonly, these algorithms utilise combinations such as 19/37 GHz, yielding reduced measurement uncertainties but at a coarse spatial resolution. Alternatively, these algorithms can solely use 89 GHz, producing a higher spatial resolution but with increased ... -
Assessing the potential of Eddy detection in MIZ using SAR and Lagrangian modeling: A test case on Fram Strait
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-08-22)The analysis of ocean eddies in the marginal ice zone via remote sensing and modeling data is a challenging task. However, it is of crucial importance for various scientific applications and anthropogenic activities in the Arctic. Models often struggle to accurately represent eddies near the MIZ due to the intricate nature of sea ice-ocean interactions, unresolved small-scale processes, and ... -
Exploring the universe through dusty visions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-05-13)Dust in space is a universal phenomenon that can be observed within our cosmic neighbourhood. Examples include the dust from the surface of the moon to the further reaches of the outer solar system, such as Saturn’s rings, and even beyond in the galactic environment. Dust in the universe has constantly challenged astronomers’ views of heavenly bodies and phenomena, often obscuring light coming from ... -
Conceptualization of a vehicle-to-grid assisted nation-wide renewable energy system – A case study with spain
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-02-08)This study explores the potential of Vehicle-to-Grid (V2G) technology in utilizing Electric Vehicle (EV) batteries for energy storage, aiming to fulfil Spain’s 2030 and 2050 energy goals. The validated Simulink model uses 3.15 million EVs in 2030 and 22.7 million EVs in 2050 as primary energy storage. The results show that Spain can achieve its 2030 target of 42 % renewable energy by utilizing ... -
The influence of socio-technical variables on vehicle-to-grid technology
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-07-04)Vehicle-to-grid technology (V2G) is a novel large scale energy storage option to improve the grid integration of renewable energy sources (RES). Using electric vehicle (EV) batteries to store and provide electricity to the grid, the intermittency of RES can be reduced. However, a successful implementation of this technology depends on various social and technological factors. This study analyses the ... -
Leveraging Explainability Maps for Group-unsupervised Robustness to Spurious Correlations
(Master thesis; Mastergradsoppgave, 2023-08-22)Shortcut learning, the tendency for models to rely on spurious correlations, is a widespread issue in deep learning. Although being a known issue, uncovering the shortcuts present in a dataset can be a difficult task. Over the last few years, explainability methods have been leveraged to find previously unknown shortcuts within mainstream datasets. However, how to best mitigate a model’s reliance ... -
Taxonomy of hybridly polarized Stokes vortex beams
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-02-15)Structured beams carrying topological defects, namely phase and Stokes singularities, have gained extensive interest in numerous areas of optics. The non-separable spin and orbital angular momentum states of hybridly polarized Stokes singular beams provide additional freedom for manipulating optical fields. However, the characterization of hybridly polarized Stokes vortex beams remains challenging ... -
Abrupt increase in Greenland melt enhanced by atmospheric wave changes
(Journal article; Tidsskriftartikkel, 2024-05-25)Recent Greenland ice-sheet melt constitutes a considerable contribution to global sea-level rise. Observations indicate an approximate zero mass balance of the ice sheet until the late 1990s, after which a strong increase in melting occurred. This cannot be attributed linearly to gradually-increasing global warming. Instead the abrupt shift has been linked to atmospheric circulation changes, although ... -
Propagating information like waves in GNNs
(Master thesis; Mastergradsoppgave, 2024-05-31)Various deep learning architectures are appearing in the field of machine learning with the goal of being able to handle various types of data, or solving inherent problems within the networks. In this thesis, we propose the idea of creating architectures based on physics partial differential equations (PDEs), where we transfer the known properties of PDEs as a method of introducing inductive bias ... -
Bruk av solceller i rehabilitering av gjenreisningsboliger i Nord-Norge – et klimaperspektiv
(Master thesis; Mastergradsoppgave, 2024-05-31)Denne masteroppgaven utforsker potensialet for solceller i rehabilitering av gjenreisningsboliger i Nord-Norge gjennom en detaljert livssyklusanalyse (LCA) for å evaluere miljøpåvirkningen av solskifertak sammenlignet med tradisjonelle skifertak. Ved hjelp av modellering i PVsyst v6.88, ble energiproduksjonen for et system på 11m2 med nominell ytelse 1.4 kW simulert og effekten av viktige ... -
Exploring methane detection with Sentinel-2 data: capabilities for monitoring landfill emissions
(Master thesis; Mastergradsoppgave, 2024-06-01)Methane is an extremely potent greenhouse gas, as it is about 80 times more effective at trapping heat than carbon dioxide. To mitigate global warming and the related consequences, reducing our emissions of methane is crucial. Therefore, being able to detect unknown releases and monitor the effects of emission mitigation efforts is essential. A few satellites with methane monitoring as one of their ... -
Antarctic ice shelf response to ocean tides and atmospheric pressure variations using satellite interferometry
(Master thesis; Mastergradsoppgave, 2024-06-02)Ice shelves, the floating extensions of the Antarctic ice sheet, are supporting the upstream ice and regulates the outflow into the ocean. They are a key component in future predictions of sea level rise, as their direct contact with both the ocean and the atmosphere makes them subject to changing climatic conditions. This thesis aims to investigate how Fimbulisen, a large ice shelf in East ... -
Uncertainty Guided Polygon Generation for Building Detection
(Mastergradsoppgave; Master thesis, 2024-06-01)Enhanced accuracy of building detection algorithms has the potential to benefit a wide array of applications, including urban planning, environmental monitoring, and disaster response efforts. However, building extraction algorithms struggle with robustness due to among others, occlusions from vegetation and shadows of nearby tall buildings, complex building shapes, and a large distributional shift ... -
Implementing renewable energy technologies in buildings: impacts of local-specific conditions, intermittency and volatile power markets
(Master thesis; Mastergradsoppgave, 2024-05-31)Increased implementations of small-scale renewable energy technologies in buildings can potentially save costs and reduce greenhouse gas emissions. The aim of this thesis is to analyse the total costs and climatic impact of implementations in major cities in Norway. Basing the analysis in data of hourly resolutions captures effects of how intermittency and volatility in the power market ... -
Seasonal Thermal Energy Storage Using Sand Batteries: Feasibility and Economic Analysis in Northern Norway
(Master thesis; Mastergradsoppgave, 2024-05-31)The global shift from fossil fuels to renewable energy sources necessitates effective energy storage solutions to address the intermittent nature of renewable power. This thesis investigates the feasibility and economic viability of using sand batteries for seasonal thermal energy storage in Northern Norway. Sand batteries leverage the high heat capacity of sand to store excess thermal energy during ... -
Assessing ice rate and ice load at Davvi wind farm using WRF model with wind turbine scheme
(Master thesis; Mastergradsoppgave, 2024-05-31)Wind farms located in cold climates are exposed to temperatures under the design limit and icing conditions, where the main challenges are production losses and mechanical failures. The goal of this thesis is to investigate the impact related to icing on the location of Davvi wind farm using Weather Research and Forecasting (WRF) model. The thesis have investigated the icing intensity and production ... -
Stellar CCD Photometry in the Auroral Zone
(Master thesis; Mastergradsoppgave, 2000-12)Observing pulsating stars in the auroral zone, seemed for many years to be an impossible task. Due to the aurora, the sky is bright and rapidly changing. Precise photometry could only be performed on stars down to 7 th. magnitude.<p> <p>A new instrument for continuous photometry, with the use of CCD technology, and windowed readout, is developed by the Astrophysics group at the University of ... -
An Investigation of Turbulence and Intermittency in the High-Latitude Ionosphere: A Multi Case Study
(Master thesis; Mastergradsoppgave, 2024-06-03)High-latitude electron density irregularities can affect technology such as the Global Navigation Satellite Services (GNSS) by degrading radio signals. These irregularities are not fully understood. In this work we investigate turbulence and intermittency in varying regions of the high- latitude ionosphere using the structure function, empirical flatness and probability density function. Our ... -
Seasonal and interannual variability in hydrography and currents along the Nansen Legacy transect across the Barents Sea
(Master thesis; Mastergradsoppgave, 2023-12-20)The Barents Sea is an Arctic shelf sea that is an important site forwater mass formation and transformation. It is characterized by interactions between Atlanticand Arctic-originWaters, and by strong seasonality in terms of alternating atmospheric and sea-ice conditions throughout the year. How these aspects impact the seasonal evolution of the water column properties is yet to be fully ... -
Leveraging tensor kernels to reduce objective function mismatch in deep clustering
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-12-29)Objective Function Mismatch (OFM) occurs when the optimization of one objective has a negative impact on the optimization of another objective. In this work we study OFM in deep clustering, and find that the popular autoencoder-based approach to deep clustering can lead to both reduced clustering performance, and a significant amount of OFM between the reconstruction and clustering objectives. To ...
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