| 1. |
- Jogestrand, T., et al.
(författare)
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Equalis kriterier för karotisdiagnostik – under kontinuerlig uppgradering
- 2012
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Ingår i: Läkartidningen. - 0023-7205 .- 1652-7518. ; 109:13, s. 702-703
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Tidskriftsartikel (refereegranskat)abstract
- Ultraljudsundersökning av karotisartärerna med så kallad duplexteknik har använts i Sverige sedan början av 1980-talet. Equalis expertgrupp för fysiologisk kärldiagnostik har nyligen presenterat sina rekommendationer för karotisdiagnostik med ultraljudsteknik.
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| 2. |
- Rohrs, J., et al.
(författare)
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Observation-based evaluation of surface wave effects on currents and trajectory forecasts
- 2012
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Ingår i: Ocean Dynamics. - : Springer Science and Business Media LLC. - 1616-7341 .- 1616-7228. ; 62:10-12, s. 1519-1533
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge of upper ocean currents is needed for trajectory forecasts and is essential for search and rescue operations and oil spill mitigation. This paper addresses effects of surface waves on ocean currents and drifter trajectories using in situ observations. The data set includes colocated measurements of directional wave spectra from a wave rider buoy, ocean currents measured by acoustic Doppler current profilers (ADCPs), as well as data from two types of tracking buoys that sample the currents at two different depths. The ADCP measures the Eulerian current at one point, as modelled by an ocean general circulation model, while the tracking buoys are advected by the Lagrangian current that includes the wave-induced Stokes drift. Based on our observations, we assess the importance of two different wave effects: (a) forcing of the ocean current by wave-induced surface fluxes and the Coriolis-Stokes force, and (b) advection of surface drifters by wave motion, that is the Stokes drift. Recent theoretical developments provide a framework for including these wave effects in ocean model systems. The order of magnitude of the Stokes drift is the same as the Eulerian current judging from the available data. The wave-induced momentum and turbulent kinetic energy fluxes are estimated and shown to be significant. Similarly, the wave-induced Coriolis-Stokes force is significant over time scales related to the inertial period. Surface drifter trajectories were analysed and could be reproduced using the observations of currents, waves and wind. Waves were found to have a significant contribution to the trajectories, and we conclude that adding wave effects in ocean model systems is likely to increase predictability of surface drifter trajectories. The relative importance of the Stokes drift was twice as large as the direct wind drag for the used surface drifter.
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| 3. |
- Rohrs, J., et al.
(författare)
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Wave-induced transport and vertical mixing of pelagic eggs and larvae
- 2014
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Ingår i: Limnology and Oceanography. - : Wiley. - 0024-3590. ; 59:4, s. 1213-1227
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Tidskriftsartikel (refereegranskat)abstract
- The transport of pelagic plankton by wind-driven ocean currents and surface gravity waves is investigated for the example of Northeast Arctic cod eggs and larvae on the coast of northern Norway. Previous studies indicate that the wave-induced drift (i.e., Stokes drift) is relevant for the transport of particles in the upper ocean. We use an ocean general circulation model together with a numerical wave prediction model and a Lagrangian particle tracking model to calculate trajectories of fish eggs and larvae. Waves are considered not only for particle drift but also for the air-sea momentum flux, its contribution to the Coriolis force, and vertical mixing. The sample species provides the advantage that many of its physical and behavioral properties are well known (e.g., egg buoyancy), allowing investigation of vertical particle displacement by turbulent mixing in response to wind forcing and wave breaking. The approach accounting for particle mixing by breaking waves enhances agreement between observed and modeled egg profiles. Results also show a general shoreward transport of particles by the Stokes drift. This wave drift exhibits a more constant direction than the Eulerian current and hence stabilizes particle diffusion to favor a dominant direction. For the case of Northeast Arctic cod, waves concentrated model eggs and larvae on average 1.5 km closer to shore, which is 20% of their total distance to the coast. This increases the residence time of first-feeding larvae close to the spawning areas compared to earlier models.
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