Blar i forfatter "Grahn, Jakob"

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    • Mapping and characterization of unstable slopes with Sentinel-1 multi-geometry InSAR (activity line 2: public sector applications) 

      Lauknes, Tom Rune; Grahn, Jakob; Royet, Line; Larsen, Yngvar; Böhme, Martina; Dehls, John F.; Kristiansen, Lene (Research report; Forskningsrapport, 2020)
      This is a high-level report that summarizes the main achievements and results of the research and development conducted in the project “Mapping and Characterization of unstable slopes with Sentinel-1 multi-geometry InSAR (activity line 2: public sector applications)”, where multi-geometry Sentinel-1 Synthetic Aperture Radar Interferometry (InSAR) is used for improving characterization of unstable ...

    • Multi-frequency radar remote sensing of sea ice. Modelling and interpretation of polarimetric multi-frequency radar signatures of sea ice 

      Grahn, Jakob (Doctoral thesis; Doktorgradsavhandling, 2018-06-08)
      This thesis deals with polarimetric multi-frequency radar signatures of sea ice. It presents a thorough background on the topic and three case studies. The first study presents a global sensitivity analysis of the fully polarimetric radar backscatter response from snow covered sea ice. The analysis is global in the sense that it takes into account the observed ranges of sea ice properties that ...

    • Recognition of polar lows in Sentinel-1 SAR images with deep learning 

      Grahn, Jakob; Bianchi, Filippo Maria (Journal article; Tidsskriftartikkel, 2022-09-06)
      In this article, we explore the possibility of detecting polar lows in C-band synthetic aperture radar (SAR) images by means of deep learning. Specifically, we introduce a novel dataset consisting of Sentinel-1 images divided into two classes, representing the presence and absence of a maritime mesocyclone, respectively. The dataset is constructed using the ECMWF reanalysis version 5 (ERA5) dataset ...

    • Snow avalanche segmentation in SAR images with Fully Convolutional Neural Networks 

      Bianchi, Filippo Maria; Grahn, Jakob; Eckerstorfer, Markus; Malnes, Eirik; Vickers, Hannah (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-10)
      Knowledge about frequency and location of snow avalanche activity is essential for forecasting and mapping of snow avalanche hazard. Traditional field monitoring of avalanche activity has limitations, especially when surveying large and remote areas. In recent years, avalanche detection in Sentinel-1 radar satellite imagery has been developed to improve monitoring. However, the current state-of-the-art ...