• Comparative study of data-driven short-term wind power forecasting approaches for the Norwegian Arctic region 

      Chen, Hao; Birkelund, Yngve; Anfinsen, Stian Normann; Yuan, Fuqing (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-26)
      This paper conducts a systemic comparative study on univariate and multivariate wind power forecasting for five wind farms inside the Arctic area. The development of wind power in the Arctic can help reduce greenhouse gas emissions in this environmentally fragile region. In practice, wind power forecasting is essential to maintain the grid balance and optimize electricity generation. This study first ...
    • Data science in wind energy: a case study for Norwegian offshore wind 

      Chen, Hao; Birkelund, Yngve; Zhang, Qixia (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-17)
      In the digital and green transitions, rapidly growing renewable energies are accumulating more and more data. Big data gives room to apply emerging data science to solve challenges in the energy sector. Offshore wind power receives accelerating attention due to its sufficient resources and cleanness. This paper uses data science, including statistical analysis and machine learning, to systematically ...
    • Data-augmented sequential deep learning for wind power forecasting 

      Chen, Hao; Birkelund, Yngve; Qixia, Zhang (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-15)
      Accurate wind power forecasting plays a critical role in the operation of wind parks and the dispatch of wind energy into the power grid. With excellent automatic pattern recognition and nonlinear mapping ability for big data, deep learning is increasingly employed in wind power forecasting. However, salient realities are that in-situ measured wind data are relatively expensive and inaccessible and ...
    • Evaluation of surface wind using WRF in complex terrain: Atmospheric input data and grid spacing 

      Solbakken, Kine; Birkelund, Yngve; Samuelsen, Eirik Mikal (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-04)
      This study evaluates a numerical weather prediction model as a tool for wind resource assessment in complex terrain and how the simulations are affected by the selection of initial and boundary conditions and various grid resolutions. Two global reanalyses, ERA-Interim and ERA5, and four grid resolutions, 27 km, 9 km, 3 km and 1 km, have been considered. The simulations have been compared to ...
    • Evaluation of the Weather Research and Forecasting (WRF) model with respect to wind in complex terrain 

      Solbakken, Kine; Birkelund, Yngve (Journal article; Tidsskriftartikkel; Peer reviewed, 2018)
      In this study the performance of the Weather Research and Forecast (WRF) model in a complex and coastal terrain has been evaluated with focus on wind resource assessment. The study area is a small community on the northern part of the island Senja, Norway. The community, with fishery and seafood as its main industry, is being limited by poor grid connection. One of the solutions is to increase ...
    • An Evaluation on Diverse Machine Learning Algorithms for Hourly Univariate Wind Power Prediction in the Arctic 

      Chen, Hao; Birkelund, Yngve (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-23)
      Wind power forecasting is crucial for wind power systems, grid load balance, maintenance, and grid operation optimization. The utilization of wind energy in the Arctic regions helps reduce greenhouse gas emissions in this environmentally vulnerable area. In the present study, eight various models, seven of which are representative machine learning algorithms, are used to make 1, 2, and 3 step ...
    • Examination of turbulence impacts on ultra-short-term wind power and speed forecasts with machine learning 

      Chen, Hao; Birkelund, Yngve; Yuan, Fuqing (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-25)
      Wind turbines’ economic and secure operation can be optimized through accurate ultra-short-term wind power and speed forecasts. Turbulence, considered as a local short-term physical wind phenomenon, affects wind power generation. This paper investigates the use of turbulence intensity for ultra-short-term predictions of wind power and speed with a wind farm in the Arctic, including and excluding ...
    • Exploring the Potential of Sentinel-1 Ocean Wind Field Product for Near-Surface Offshore Wind Assessment in the Norwegian Arctic 

      Khachatrian, Eduard; Asemann, Patricia; Lihong, Zhou; Birkelund, Yngve; Ezau, Igor; Ricaud, Benjamin (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-24)
      The exploitation of offshore wind resources is a crucial step towards a clean energy future. It requires an advanced approach for high-resolution wind resource evaluations. We explored the suitability of the Sentinel-1 Level-2 OCN ocean wind field (OWI) product for offshore wind resource assessments. The SAR data were compared to in situ observations and three reanalysis products: the global ...
    • The First Magnetotelluric Image of the Lithospheric-Scale Geological Architecture in Central Svalbard, Arctic Norway 

      Beka, Thomas Ibsa; Smirnov, Maxim; Bergh, Steffen G; Birkelund, Yngve (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-12-17)
      Magnetotelluric data, collected from 30 stations on Spitsbergen as part of a reconnaissance geothermal resource assessment along a profile with 0.53-km spacing in 0.0031000-s period range, were used to develop a lithospheric-scale two-dimensional (2D) resistivity model, heretofore unavailable for the region. Inverting the determinant of the impedance tensor in 2D, we found the smoothest model ...
    • Machine learning forecasts of Scandinavian numerical weather prediction wind model residuals with control theory for wind energy 

      Chen, Hao; Zhang, Qixia; Birkelund, Yngve (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-22)
      The quality of wind data from the numerical weather prediction significantly influences the accuracy of wind power forecasting systems for wind parks. Therefore, an in-depth investigation of these wind data themselves is essential to improve wind power generation efficiency and maintain grid reliability. This paper proposes a novel framework based on machine learning for concurrently analyzing and ...
    • Magnetotelluric signatures of the complex tertiary fold–thrust belt and extensional fault architecture beneath Brøggerhalvøya, Svalbard 

      Beka, Thomas Ibsa; Bergh, Steffen G; Smirnov, Maxim; Birkelund, Yngve (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-18)
      Magnetotelluric (MT) data were recently collected on Brøggerhalvøya, Svalbard, in a 0.003–1000 s period range along a curved WNW–ESE profile. The collected data manifested strong three-dimensional (3D) effects. We modelled the full impedance tensor with tipper and bathymetry included in 3D, and benchmarked the result with determinant data two-dimensional (2D) inversion. The final inversion results ...
    • Noise-intensification data augmented machine learning for day-ahead wind power forecast 

      Chen, Hao; Birkelund, Yngve; Batalden, Bjørn-Morten; Barabadi, Abbas (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-10)
      The day-ahead wind power forecast is essential for the designation of dispatch schedules for the grid and rational arrangement for production planning by power generation companies. This paper specifically investigates the effect of adding noise to the original wind data for forecasting models. Linear regression, artificial neural networks, and adaptive boosting predictive models based on ...
    • Preliminary Assessment of Remote Wind Sites 

      Bilal, Muhammad; Araya, Guillermo; Birkelund, Yngve (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-08)
      Wind energy is becoming a reliable and affordable source of clean energy and is rapidly expanding to remote places around the world. A crucial input for wind farming prospect is the assessment of potential wind sites. Sites, especially remotely located, often do not have a wind resource map and thus lack credible historical records of wind resources. Measurement campaigns to map these sites are ...
    • Probability distributions for wind speed volatility characteristics: A case study of Northern Norway 

      Chen, Hao; Anfinsen, Stian Normann; Birkelund, Yngve; Yuan, Fuqing (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11)
      The Norwegian Arctic is rich in wind resources. The development of wind power in this region can boost green energy and also promote local economies. In wind power engineering, it is a tremendous advantage to base projects on a sound understanding of the intrinsic properties of wind resources in an area. Wind speed volatility, a phenomenon that strongly affects wind power generation, has not received ...
    • Radiometric temperature reading of a hot ellipsoidal object inside the oral cavity by a shielded microwave antenna put flush to the cheek 

      Klemetsen, Øystein; Jacobsen, Svein Ketil; Birkelund, Yngve (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      A new scheme for detection of vesicoureteral reflux (VUR) in children has recently been proposed in the literature. The idea is to warm bladder urine via microwave exposure to at least fever temperatures and observe potential urine reflux from the bladder back to the kidney(s) by medical radiometry. As a preliminary step toward realization of this detection device, we present non-invasive temperature ...
    • A southern, middle, and northern Norwegian offshore wind energy resources analysis by a transfer learning method for Energy Internet 

      Chen, Hao; Birkelund, Yngve; Ricaud, Benjamin; Zhang, Qixia (Journal article; Tidsskriftartikkel; Peer reviewed, 2023)
      As renewable energy sources offshore wind energy develop quickly, countries like Norway with long coastlines are exploring their potential. However, the diverse wind resources across different regions of Norway present challenges for study for effective utilization of offshore wind energy. This study proposes a novel method that utilizes transfer learning techniques to analyse the resource differences ...
    • Synthetic Aperture Focusing of Ultrasonic Data From Multilayered Media Using an Omega-K Algorithm 

      Skjelvareid, Martin H.; Olofsson, Tomas; Birkelund, Yngve; Larsen, yngvar (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      The synthetic aperture focusing technique (SAFT) is used to create focused images from ultrasound scans. SAFT has traditionally been applied only for imaging in a single medium, but the recently introduced phase shift migration (PSM) algorithm has expanded the use of SAFT to multilayer structures. In this article we present a similar focusing algorithm called multi-layer omega-k (MULOK), which ...
    • Three-dimensional ultrasonic imaging in multilayered media 

      Skjelvareid, Martin Hansen; Olofsson, Tomas; Birkelund, Yngve (Conference object; Konferansebidrag, 2011)
      The synthetic aperture focusing technique is a method for focusing ultrasonic scans used in nondestructive testing. Traditionally, the technique has mainly been used for contact testing, where the speed of sound is constant throughout the whole medium, but a number of recently proposed algorithms have extended the technique to multilayered media. One important application for such multilayer methods ...
    • Ultrasonic imaging of pitting using multilayer synthetic aperture focusing 

      Skjelvareid, Martin Hansen; Olofsson, Tomas; Birkelund, Yngve (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      Synthetic aperture focusing is known to increase both the lateral resolution and signal-to-noise level of pulse-echo ultrasonic images. In this paper, the use of synthetic aperture imaging for detection and sizing of pitting in a plate is considered. It is assumed that a water layer is present between the transducer and the plate, and that the pitting is on the back side of the plate, seen from the ...
    • Wind power predictions in complex terrain using analog ensembles 

      Birkelund, Yngve; Alessandrini, Stefano; Byrkjedal, Øyvind; Monache, Luca Delle (Journal article; Tidsskriftartikkel, 2018)