Browsing Bergen Open Research Archive by Author "Röhrs, Johannes"

Now showing items 1-7 of 7

    • Constraining energetic slope currents through assimilation of high-frequency radar observations 

      Sperrevik, Ann Kristin; Christensen, Kai Håkon; Röhrs, Johannes (Peer reviewed; Journal article, 2015-03-11)
      Assimilation of high-frequency (HF) radar current observations and CTD hydrography is performed with the 4D-Var analysis scheme implemented in the Regional Ocean Modeling System (ROMS). We consider both an idealized case, ...

    • Current shear and turbulence during a near-inertial wave 

      Röhrs, Johannes; Halsne, Trygve; Sutherland, Graig; Dagestad, Knut-Frode; Hole, Lars Robert; Brostrøm, Gøran; Christensen, Kai Håkon (Journal article; Peer reviewed, 2023-04-11)
      Surface currents and turbulent mixing were observed during a near-inertial wave (NIW) using an accousting doppler current profiler (ADCP) and satellite-tracked drifters. Drifter trajectories sampled at three depth levels ...

    • The effect of vertical mixing on the horizontal drift of oil spills 

      Röhrs, Johannes; Dagestad, Knut-Frode; Asbjørnsen, Helene; Nordam, Tor; Skancke, Jørgen; Jones, Cathleen; Brekke, Camilla (Peer reviewed; Journal article, 2018)
      Vertical and horizontal transport mechanisms for marine oil spills are investigated using numerical model simulations. To realistically resolve the 3-D development of a spill on the ocean surface and in the water column, ...

    • Evaluating the leeway coefficient of ocean drifters using operational marine environmental prediction systems 

      Sutherland, Graig; Soontiens, Nancy; Davidson, Fraser; Smith, Gregory C.; Bernier, Natacha; Blanken, Hauke; Schillinger, Douglas; Marcotte, Guillaume; Röhrs, Johannes; Dagestad, Knut-Frode; Christensen, Kai Håkon; Breivik, Øyvind (Journal article; Peer reviewed, 2020)
      The water following characteristics of six different drifter types are investigated using two different operational marine environmental prediction systems: one produced by Environment and Climate Change Canada (ECCC) and ...

    • Impact of data assimilation on Eulerian versus Lagrangian estimates of upper ocean transport 

      Sperrevik, Ann Kristin; Röhrs, Johannes; Christensen, Kai Håkon (Peer reviewed; Journal article, 2017)
      Using four-dimensional variational analysis, we produce an estimate of the state of a coastal region in Northern Norway during the late winter and spring in 1984. We use satellite sea surface temperature and in situ ...

    • OpenDrift v1.0: A generic framework for trajectory modelling 

      Dagestad, Knut-Frode; Röhrs, Johannes; Breivik, Øyvind; Ådlandsvik, Bjørn (Peer reviewed; Journal article, 2018-04-13)
      OpenDrift is an open-source Python-based framework for Lagrangian particle modelling under development at the Norwegian Meteorological Institute with contributions from the wider scientific community. The framework is ...

    • Surface wave effects in the upper ocean and consequences for biological modeling 

      Röhrs, Johannes (Doctoral thesis, 2014-03-21)
      Effects of surface gravity waves on particle transport and currents in the upper ocean are studied using field observations and numerical models. Knowledge on upper ocean particle drift is needed for plankton transport ...