Recent additions

  • Winter storms accelerate the demise of sea ice in the Atlantic sector of the Arctic Ocean 

    Graham, Robert M.; Itkin, Polona; Meyer, Amelie; Sundfjord, Arild; Spreen, Gunnar; Smedsrud, Lars H.; Liston, Glen E.; Cheng, Bin; Cohen, Lana; Divine, Dmitry; Fer, Ilker; Fransson, Agneta; Gerland, Sebastian; Haapala, Jari; Hudson, Stephen R.; Johansson, Malin; King, Jennifer A.; Merkouriadi, Ioanna; Peterson, Algot Kristoffer; Provost, Christine; Randelhoff, Achim; Rinke, Annette; Rösel, Anja; Sennechael, Nathalie; Walden, Von P.; Duarte, Pedro; Assmy, Philipp; Steen, Harald; Granskog, Mats A. (Journal article; Peer reviewed, 2019-06-25)
    A large retreat of sea-ice in the ‘stormy’ Atlantic Sector of the Arctic Ocean has become evident through a series of record minima for the winter maximum sea-ice extent since 2015. Results from the Norwegian young sea ICE (N-ICE2015) expedition, a five-month-long (Jan-Jun) drifting ice station in first and second year pack-ice north of Svalbard, showcase how sea-ice in this region is frequently ...
  • Authenticating the presence of a relativistic massive black hole binary in OJ 287 using its general relativity centenary flare: Improved orbital parameters 

    Dey, Lankeswar; Valtonen, MJ; Gopakumar, A; Zola, S; Hudec, R; Pihajoki, P; Ciprini, S; Matsumoto, K; Sadakane, K; Kidger, M; Nilsson, K; Mikkola, S; Sillanpää, A; Takalo, LO; Lehto, HJ; Berdyugin, A; Piirola, V; Jermak, H; Baliyan, KS; Pursimo, T; Caton, DB; Alicavus, F; Baransky, A; Blay, P; Boumis, P; Boyd, D; Campas Torrent, M; Campos, F; Carrillo Goméz, J; Chandra, S; Chavushyan, V; Dalessio, J; Debski, B; Drozdz, M; Er, H; Erdem, A; Escartin Pérez, A; Fallah Ramazani, V; Filippenko, AV; Gafton, E; Ganesh, S; Garcia, F; Gazeas, K; Godunova, V; Goméz Pinilla, F; Gopinathan, M; Haislip, JB; Harmanen, J; Hurst, G; Janik, J; Jelinek, M; Joshi, A; Kagitani, M; Karjalainen, R; Kaur, N; Keel, WC; Kouprianov, VV; Kundera, T; Kurowski, S; Kvammen, Andreas; Lacluyze, AP; Lee, BC; Liakos, A; Lindfors, E; Lozano de Haro, J; Mugrauer, M; Naves Nogues, R; Neely, AW; Nelson, RH; Ogloza, W; Okano, S; Pajdosz-Śmierciak, U; Pandey, JC; Perri, M; Poyner, G; Provencal, J; Raj, A; Reichart, DE; Reinthal, R; Reynolds, T; Saario, J; Sadegi, S; Sakanoi, T; Salto González, J-L; Sameer, S; Schweyer, T; Simon, A; Siwak, M; Soldán Alfaro, FC; Sonbas, E; Steele, I; Stocke, JT; Strobl, J; Tomov, T; Tremosa Espasa, L; Valdes, JR; Perez, J Valero; Verrecchia, F; Webb, JR; Yoneda, M; Zejmo, M; Zheng, W; Zielinski, P (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-05)
    Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show that observations associated with the binary black hole (BBH) central engine of blazar OJ 287 demand the inclusion of gravitational radiation reaction effects beyond the quadrupolar order. It turns out that even the effects ...
  • Shock location and CME 3D reconstruction of a solar type II radio burst with LOFAR 

    Zucca, P; Morosan, D; Rouillard, A; Fallows, Richard; Gallagher, P. T.; Magdalenic, J; Klein, K-L; Mann, G; Vocks, C; Carley, E. P.; Bisi, M. M.; Kontar, E. P.; Rothkaehl, Hanna; Dabrowski, B; Krankowski, A; Anderson, James; Asgekar, A; Bell, M. E.; Bentum, M. J.; Best, P; Blaauw, R; Breitling, F.; Broderick, J. W.; Brouw, W. N.; Brüggen, M.; Butcher, H. R.; Ciardi, B.; de Geus, E.; Deller, A.; Duscha, S.; Eislöffel, J.; Garrett, M. A.; Grießmeier, J. M.; Gunst, A. W.; Heald, G.; Hoeft, M.; Hörandel, J.; Iacobelli, M.; Juette, E; Karastergiou, A.; van Leeuwen, J.; McKay, Derek; Mulder, H.A.; Munk, H.; Nelles, A.; Orru, E.; Paas, H.; Pandey, V. N.; Pekal, R.; Pizzo, R.; Polatidis, A. G.; Reich, W.; Rowlinson, A.; Schwarz, D. J.; Shulevski, A.; Sluman, J.; Smirnov, O.V.; Sobey, C.; Soida, M.; Thoudam, S.; Toribio, M. C.; Vermeulen, R.; van Weeran, R. J.; Wucknitz, O.; Zarka, P. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-19)
    <p><i>Context - </i>Type II radio bursts are evidence of shocks in the solar atmosphere and inner heliosphere that emit radio waves ranging from sub-meter to kilometer lengths. These shocks may be associated with coronal mass ejections (CMEs) and reach speeds higher than the local magnetosonic speed. Radio imaging of decameter wavelengths (20–90 MHz) is now possible with the Low Frequency Array ...
  • Classification of Micro-Damage in Piezoelectric Ceramics Using Machine Learning of Ultrasound Signals 

    Tripathi, Gaurav; Anowarul, Habib; Agarwal, Krishna; Prasad, Dilip K. (Journal article; Peer reviewed, 2019-09-28)
    Ultrasound based structural health monitoring of piezoelectric material is challenging if a damage changes at a microscale over time. Classifying geometrically similar damages with a difference in diameter as small as 100 m is difficult using conventional sensing and signal analysis approaches. Here, we use an unconventional ultrasound sensing approach that collects information of the entire ...
  • Multi-scale measurements of mesospheric aerosols and electrons during the MAXIDUSTY campaign 

    Antonsen, Tarjei; Havnes, Ove; Spicher, Andres (Journal article; Peer reviewed, 2019-04-08)
    We present in situ measurements of small-scale fluctuations in aerosol populations as recorded through a mesospheric cloud system from the Faraday cups DUSTY and MUDD during on the MAXIDUSTY-1 and 1B sounding rocket payloads launched in the summer of 2016. <br>Two mechanically identical DUSTY probes mounted with an inter-spacing of ∼10 cm recorded very different currents, with strong spin modulation, ...
  • Gaussian Process Sensitivity Analysis for Oceanic Chlorophyll Estimation 

    Blix, Katalin; Camps-Valls, Gustau; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-01-04)
    Gaussian process regression (GPR) has experienced tremendous success in biophysical parameter retrieval in the past years. The GPR provides a full posterior predictive distribution so one can derive mean and variance predictive estimates, i.e., point-wise predictions and associated confidence intervals. GPR typically uses translation invariant covariances that make the prediction function very ...
  • Wind power predictions in complex terrain using analog ensembles 

    Birkelund, Yngve; Alessandrini, Stefano; Byrkjedal, Øyvind; Monache, Luca Delle (Journal article; Tidsskriftartikkel, 2018)
  • Unsupervised domain adaptation for automatic estimation of cardiothoracic ratio 

    Dong, Nanqing; Kampffmeyer, Michael C.; Liang, Xiaodan; Wang, Zeya; Dai, Wei; Xing, Eric P. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-26)
    The cardiothoracic ratio (CTR), a clinical metric of heart size in chest X-rays (CXRs), is a key indicator of cardiomegaly. Manual measurement of CTR is time-consuming and can be affected by human subjectivity, making it desirable to design computer-aided systems that assist clinicians in the diagnosis process. Automatic CTR estimation through chest organ segmentation, however, requires large amounts ...
  • Time Series Kernel Similarities for Predicting Paroxysmal Atrial Fibrillation from ECGs 

    Bianchi, Filippo Maria; Livi, Lorenzo; Ferrante, Alberto; Milosevic, Jelena; Miroslaw, Malek (Journal article; Tidsskriftartikkel, 2018)
    We tackle the problem of classifying Electrocardiography (ECG) signals with the aim of predicting the onset of Paroxysmal Atrial Fibrillation (PAF). Atrial fibrillation is the most common type of arrhythmia, but in many cases PAF episodes are asymptomatic. Therefore, in order to help diagnosing PAF, it is important to design procedures for detecting and, more importantly, predicting PAF episodes. ...
  • The deep kernelized autoencoder 

    Kampffmeyer, Michael C.; Løkse, Sigurd; Bianchi, Filippo Maria; Jenssen, Robert; Livi, Lorenzo (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-18)
    Autoencoders learn data representations (codes) in such a way that the input is reproduced at the output of the network. However, it is not always clear what kind of properties of the input data need to be captured by the codes. Kernel machines have experienced great success by operating via inner-products in a theoretically well-defined reproducing kernel Hilbert space, hence capturing topological ...
  • Results from the intercalibration of optical low-light calibration sources 2011 

    Brändström, B. Urban E.; Enell, Carl-Fredrik; Widell, Ola; Hansson, Thord; Whiter, Daniel; Mäkinen, Sanna; Mikhaylova, Daria; Axelsson, Katarina; Sigernes, Fred; Gulbrandsen, Njål; Schlatter, Nicola M.; Gjendem, Amund Gjerde; Cai, L.; Reistad, Jone Peter; Daae, Marianne; Demissie, Teferi Dejene; Andalsvik, Yngvild Linnea; Roberts, Owen; Poluyanov, Stepan Viktorovich; Chernouss, Sergey (Journal article; Tidsskriftartikkel; Peer reviewed, 2012-05-03)
    Following the 38th Annual European Meeting on Atmospheric Studies by Optical Methods in Siuntio in Finland, an intercalibration workshop for optical low light calibration sources was held in Sodankylä, Finland. The main purpose of this workshop was to provide a comparable scale for absolute measurements of aurora and airglow. All sources brought to the intercalibration workshop were compared to the ...
  • Urban land cover classification with missing data modalities using deep convolutional neural networks 

    Kampffmeyer, Michael C.; Salberg, Arnt Børre; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-14)
    Automatic urban land cover classification is a fundamental problem in remote sensing, e.g., for environmental monitoring. The problem is highly challenging, as classes generally have high interclass and low intraclass variances. Techniques to improve urban land cover classification performance in remote sensing include fusion of data from different sensors with different data modalities. However, ...
  • A new method of inferring the size, number density, and charge of mesospheric dust from its in situ collection by the DUSTY probe 

    Havnes, Ove; Antonsen, Tarjei; Baumgarten, Gerd; Hartquist, Thomas W.; Biebricher, Alexander; Fredriksen, Åshild; Friedrich, Martin; Hedin, Jonas (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-15)
    <p>We present a new method of analyzing measurements of mesospheric dust made with DUSTY rocket-borne Faraday cup probes. It can yield the variation in fundamental dust parameters through a mesospheric cloud with an altitude resolution down to 10 cm or less if plasma probes give the plasma density variations with similar height resolution. A DUSTY probe was the first probe that unambiguously detected ...
  • Weather situation during observed ship-icing events off the coast of Northern Norway and the Svalbard archipelago 

    Samuelsen, Eirik Mikal; Graversen, Rune (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-19)
    Ship icing may lead the ship and crew in great jeopardy. Usually, predictions of such ice build-up are based on the modelling of the heat fluxes capable of freezing sea water originated from wave-ship interactions. This study, on the other hand, follows a different and more general approach by investigating the relationship between the weather situation and icing both using observed parameters from ...
  • Impact of assimilating sea ice concentration, sea ice thickness and snow depth in a coupled ocean-sea ice modelling system 

    Fritzner, Sindre Markus; Graversen, Rune; Christensen, Kai Håkon; Rostosky, Philip; Wang, Keguang (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-08)
    The accuracy of the initial state is very important for the quality of a forecast, and data assimilation is crucial for obtaining the best-possible initial state. For many years, sea-ice concentration was the only parameter used for assimilation into numerical sea-ice models. Sea-ice concentration can easily be observed by satellites, and satellite observations provide a full Arctic coverage. During ...
  • SKIM, a Candidate Satellite Mission Exploring Global Ocean Currents and Waves 

    Ardhuin, Fabrice; Brandt, Peter; Gaultier, Lucile; Donlon, Craig James; Battaglia, Alessandro; Boy, Francois; Casal, Tania; Chapron, Bertrand; Collard, Fabrice; Cravatte, Sophie; Delouis, Jean-Marc; De Witte, Erik; Dibarboure, Gerald; Engen, Geir; Johnsen, Harald; Lique, Camille; López-Dekker, Paco; Maes, Christophe; Martin, Adrien; Marie, Louis; Menemenlis, Dimitris; Nouguier, Frederic; Peureux, Charles; Rampal, Pierre; Ressler, Gerhard; Rio, Marie-Helene; Rommen, Bjorn; Shutler, Jamie D.; Suess, Martin; Tsamados, Michel; Ubelmann, Clement; van Sebille, Erik; van den Oever, Martin; Stammer, Detlef (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-30)
    The Sea surface KInematics Multiscale monitoring (SKIM) satellite mission is designed to explore ocean surface current and waves. This includes tropical currents, notably the poorly known patterns of divergence and their impact on the ocean heat budget, and monitoring of the emerging Arctic up to 82.5°N. SKIM will also make unprecedented direct measurements of strong currents, from boundary currents ...
  • Deep Reinforcement Learning for Query-Conditioned Video Summarization 

    Zhang, Yujia; Kampffmeyer, Michael C.; Zhao, Xiaoguang; Tan, Min (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-21)
    Query-conditioned video summarization requires to (1) find a diverse set of video shots/frames that are representative for the whole video, and that (2) the selected shots/frames are related to a given query. Thus it can be tailored to different user interests leading to a better personalized summary and differs from the generic video summarization which only focuses on video content. Our work targets ...
  • Sparse signal recovery in MIMO specular meteor radars with waveform diversity 

    Urco, Miguel; Chau, Jorge Luis; Weber, Tobias; Vierinen, Juha; Volz, Ryan (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-15)
    Since the 1950s, specular meteor radars (SMRs) have been used to study the mesosphere and lower thermosphere (MLT) dynamics. Atmospheric parameters derived from SMRs are highly dependent on the number of detected meteors and the accuracy of the meteors' locations. Recently, incoherent and coherent multiple-input-multiple-output (MIMO) radar approaches combined with waveform diversity have been ...
  • Investigation of exceptionally radar-dark regions on the lunar nearside 

    Tveito, Torbjørn; Vierinen, Juha; Serrano, Alessandra (Conference object; Konferansebidrag, 2019-08)
    Remote sensing of planetary surfaces is an effective method for gaining knowledge of the processes that shape the planetary bodies in our solar system. This is useful for uncovering the environment of the primordial solar system and to study the current state of the upper crusts of the other planets in our neighborhood. A recent 6-meter wavelength polarimetric radar map of the Moon [?] showed ...
  • The Thorpex polar low analysed with AROME-Arctic 

    Stoll, Patrick J.; Valkonen, Teresa M.; Graversen, Rune G.; Noer, Gunnar (Conference object; Konferansebidrag, 2019-04)

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