Bjørn Gjevik

• Lynge, Birgit Kjoss; Hjelmervik, Karina Bakkeløkken & Gjevik, Bjørn (2013). Storm surge and tidal interaction in the Tjeldsund channel, northern Norway. Ocean Dynamics. ISSN 1616-7341. 63(7), s. 723–739. doi: 10.1007/s10236-013-0625-1. Vis sammendrag

  The aim of this study is to investigate tide–surge interaction in narrow channels with complex and relatively shallow topography. A high-resolution depth-integrated tidal and storm surge model has been implemented for the Tjeldsund channel which is an important sailing lane in northern Norway. A horizontal grid resolution down to 50 m is applied in order to represent the complex bottom topography and the formation of jets and small-scale eddies. Two typically storm surge events in December 2004 have been examined in detail. The tide–surge interaction is found to influence the generation of higher harmonics and the formation of eddies in the current field. In some cases, the magnitude of storm surge currents may reach the same magnitude as the tidal currents enhancing the formation of jets and eddies.

• Bondevik, Stein; Gjevik, Bjørn & Sørensen, Mathilde B. (2013). Norwegian seiches from the giant 2011 Tohoku earthquake. Geophysical Research Letters. ISSN 0094-8276. 40(13), s. 3374–3378. doi: 10.1002/grl.50639.
• Teigen, Sigurd Henrik; Nilsen, Frank; Skogseth, Ragnheid; Gjevik, Bjørn & Beszczynska-Möller, A. (2011). Baroclinic instability in the West Spitsbergen Current. Journal of Geophysical Research (JGR): Oceans. ISSN 2169-9275. 116. doi: 10.1029/2011JC006974.
• Teigen, Sigurd Henrik; Nilsen, Frank & Gjevik, Bjørn (2010). Barotropic instability in the West Spitsbergen Current. Journal of Geophysical Research (JGR): Oceans. ISSN 2169-9275. 115. doi: 10.1029/2009JC005996.
• Lynge, Birgit Kjoss; Berntsen, J & Gjevik, Bjørn (2010). Numerical studies of dispersion due to tidal flow through Moskstraumen, northern Norway. Ocean Dynamics. ISSN 1616-7341. 60(4), s. 907–920. doi: 10.1007/s10236-010-0309-z.
• Christensen, Ole; Kostylev, Vladimir; Longva, Oddvar; Thorsnes, Terje; Courtney, Robert C. & Gjevik, Bjørn (2009). Correlations of geological and biological elements in marine habitat mapping in glaciated areas; field tests from the coast of More and Romsdal County, western Norway. Norsk Geologisk Tidsskrift. ISSN 0029-196X. 89(3), s. 229–246.
• Pankratz, Normann; Natvig, Jostein Roald; Gjevik, Bjørn & Noelle, Sebastian (2007). High-order well-balanced finite-volume schemes for barotropic flows: Development and numerical comparisons. Ocean Modelling. ISSN 1463-5003. 18, s. 53–79. doi: 10.1016/j.ocemod.2007.03.005.
• Gjevik, Bjørn (2006). Flo og fjære langs kysten av Norge. I Aksnes, Kaare (Red.), Almanakk for Norge for året etter Kristi fødsel 2007. Gyldendal Norsk Forlag A/S. ISSN 8205354944. s. 48–51.
• Orre, Steinar; Gjevik, Bjørn & LaCasce, Joseph H. (2006). Characterizing chaotic dispersion in a coastal tidal model. Continental Shelf Research. ISSN 0278-4343. 26, s. 1360–1374. doi: 10.1016/j.csr.2005.11.015.
• Nilsen, F; Gjevik, Bjørn & Schauer, U (2006). Cooling of the West Spitsbergen Current: Isopycnal diffusion by topographic vorticity waves. Journal of Geophysical Research (JGR). ISSN 0148-0227. 111.
• Gjevik, Bjørn; Hareide, D.; Lynge, B.K.; Ommundsen, A; Skailand, J.H. & Urheim, H.B. (2006). Implementation of High Resolution Tidal Current Fields in Electronic Navigational Chart Systems. Marine Geodesy. ISSN 0149-0419. 29, s. 1–17.
• Thiem, Øyvind; Thiem, O; Berntsen, Jarle & Gjevik, Bjørn (2006). Development of eddies in an idealised shelf slope area due to an along slope barotropic jet. Continental Shelf Research. ISSN 0278-4343. 26, s. 1481–1495.
• Gjevik, Bjørn; Flather, R.A. & Hareide, D. (2004). Sea level oscillahions with 6-h period in the North Sea 29-31 October 2000. An analysis of data from stations in the northen North Sea and along the western coast of Norway. Ocean Dynamics. ISSN 1616-7341. 54, s. 477–488. doi: 10.1007/S10236-004-0093-8.
• Davies, Alan M.; Xing, Jiuxing & Gjevik, Bjørn (2003). Barotropic eddy generation by flow instability at the shelf edge: Sensitvity to open boundary conditions, inflow and diffusion. Journal of Geophysical Research (JGR). ISSN 0148-0227. 108(C2), s. 17-1–17-15.
• Moe, Halvard; Gjevik, Bjørn & Ommundsen, Atle (2003). A high resolution tidal model for the coast of Møre and Trøndelag, Mid-Norway. Norsk Geografisk Tidsskrift. ISSN 0029-1951. 57, s. 65–82.
• Gjevik, Bjørn; Moe, Halvard & Ommundsen, Atle (2002). Idealized model simulations of barotropic flow on the Catalan shelf. Continental Shelf Research. ISSN 0278-4343. 22, s. 173–198. Vis sammendrag

  The effect of along shelf variation in shelf width on barotropic shelf edge flows and topographic shelf waves are investigated with a numerical model. The model topography represents a gradual transition from a narrow straight to a broader straight shelf region. It is designed primary to model the Catalan shelf on the northeastern Mediterranean coast of Spain, but the results obtained here are of general validity and will also apply to shelf flow under similar conditions elsewhere. The numerical experiments are carried out with flow imposed, both steady and oscillatory, at the upstream end of the narrow shelf region. With a prescribed shelf edge flow there is a strong tendency for topographic steering in the transition zone. The adjustment is found to take place on a short time scale of 2-5 days set by propagating wave modes rather than by advection. Bottom friction effects do not lead to significant on-shelf leakage of the flow. Flow instability and eddy formation are found to occur, even in cases where the potential vorticity for the imposed flow does not have a local maximum on the shelf slope. The instability leads to development of anticyclonic eddies on the narrow shelf which undergo strong non-linear adjustment at the transition zone from a narrow to a broader shelf. On the broad section of the shelf near the transition zone there is a tendency for formation of a large anticyclonic eddy. Bottom friction is found to influence the flow instability and the formation of eddies in cases where the flow is marginal for instability and growth of eddies. Particle tracking has been performed in order to study cross shelf mixing and transport. Finally we have studied the current response due to a concentrated wind stress jet acting perpendicular to the coast line in the transition zone between the narrow and the broad shelf regions. A dipolar eddy structure is found to develop with the axis of the dipole tilting about 30 degrees with the axis of the wind jet and with strong current shear in the zone near the dipole axis.

• Moe, Halvard; Ommundsen, Atle & Gjevik, Bjørn (2002). A high resolution tidal model for the area around The Lofoten Islands, Northern Norway. Continental Shelf Research. ISSN 0278-4343. 22, s. 485–504. Vis sammendrag

  A depth-integrated numerical model with grid resolution 500 m has been used to simulate tides around The Lofoten Islands in northern Norway. The model spans more than 3 deg latitude and covers a sea area of approximately 1.2*10^5 km^2. The fine spatial resolution resolves the important fine scale features of the bottom topography on the shelf and the complex coastline with fjords and islands. Boundary conditions at the oceanic sides of the model domain are obtained by interpolation from a large scale tidal model covering the Nordic Seas and implemented with the flow relaxation scheme (FRS). The semi-diurnal components M2, S2 and N2 and the diurnal component K1 are simulated. Harmonic constants for sea level are compared with observations from 21 stations. The best fit is found for the M2 component with a standard deviation between the observed and modelled amplitude and phase of 2.3 cm and 2.5 degrees, respectively. The standard deviation for the other smaller components ranges between 1.5 to 2.8 cm and 5.3 to 16.7 degrees. Current fields from the model are compared with observations in four locations; the Moskenes sound, the Gimsøy channel, the Tjeldsund channel and the Sortland channel. In the Sortland channel the model predicts a dominant diurnal K1 current in agreement with observations.

• Gjevik, Bjørn; Moe, Halvard & Ommundsen, Atle (2002). Idealized Model Simulations of Barotopic Flow on the Catalan Shelf. Continental Shelf Research. ISSN 0278-4343.
• Gjevik, Bjørn; Pedersen, Geir Kleivstul; Dybesland, Elen; Harbitz, Carl Bonnevie; Miranda, P.M.A. & Baptista, M.A. [Vis alle 10 forfattere av denne artikkelen] (1997). Modeling tsunamis from earthquake sources near Gorringe Bank southwest of Portugal. Journal of Geophysical Research (JGR): Oceans. ISSN 2169-9275. 102(C13), s. 931–949. doi: 10.1029/97JC02179. Vis sammendrag

  The Azores-Gibraltar fracture zone with the huge bathymetric reliefs in the area southwest of Portugal is believed to have been the source of large historic tsunami events. This report describes simulations of tsunami generation and propagation from sources near the Gorringe Bank. The well-documented 1969 tsunami event is examined both with a ray-tracing technique and with finite difference models based on various shallow water equations. Both methods show that the most likely source location is southeast of the Gorringe Bank near the epicenter location determined from seismic data. The tsunami source is calculated by formulas given by Okada [1985] for surface deformation of an elastic half-space caused by faulting. Observed wave amplitude and travel time and values computed from an initial wave field according to Okada [1985] formulas show acceptable agreement for most stations along the coast of Portugal and Spain. However, in order to explain a large primary wave with downward displacement observed on the coast of Morocco, an alternative source model with a larger area of downward displacement has been introduced. This also leads to a better overall fit with observed travel time. Implications for disastrous events, as the one in 1755, are also discussed. Linear hydrostatic shallow water models are used for most of the simulations, but the importance of nonlinearity and dispersion is examined with the Boussinesq equations. The sensitivity of the solution to changes in the location and the strength of the source is discussed, and a series of grid refinement studies are performed in order to assess the accuracy of the simulations.

• Gjevik, Bjørn; Moe, Halvard & Ommundsen, Atle (1997). Sources of the Maelstrom. Nature. ISSN 0028-0836. 388, s. 837–838.
• Røed, Lars Petter; Hackett, Bruce; Gjevik, Bjørn & Eide, Lars Ingolf (1995). A review of the Metocean Modeling Project (MOMOP) Part 1: Model comparison study. I Lynch, Daniel R. & Davies, Alan M. (Red.), Quantitative Skill Assessment for Coastal Ocean Models. American Geophysical Union (AGU). ISSN 0-87590-261-8. s. 285–305.
• Hackett, Bruce; Røed, Lars Petter; Gjevik, Bjørn; Martinsen, Eivind A. & Eide, Lars Ingolf (1995). A review of the Metocean Modeling Project (MOMOP) Part 2: Model validation study. I Lynch, Daniel R. & Davies, Alan M. (Red.), Quantitative Skill Assessment for Coastal Ocean Models. American Geophysical Union (AGU). ISSN 0-87590-261-8. s. 307–327.
• Harbitz, Carl Bonnevie; Pedersen, Geir Kleivstul & Gjevik, Bjørn (1993). Numerical Simulations of Large Water Waves due to Landslides. Journal of Hydraulic Engineering. ISSN 0733-9429. 1119(12). doi: 10.1061/%28ASCE%290733-9429%281993%29119%3A12%281325%29. Vis sammendrag

  A mathematical model based on the hydrodynamic shallow water equations is developed for numerical simulation of slide generated waves in fjords. The equations are solved numerically by a finite difference technique. To examine the performance of the numerical model we have simulated the slide catastrophe in Tafjord, western Norway, 1934. The predicted runup heights are in good agreement with measured runup heights. The effects of wave amplification are estimated in runup zones with gentle beach slopes. The model results reveal wave energy trapping due to the fjord geometry. This causes standing wave oscillations in accordance with the observations.

• Martinsen, Eivind A.; Gjevik, Bjørn & Røed, Lars Petter (1979). A numerical model for long barotropic waves and storm surges along the western coast of Norway. Journal of Physical Oceanography. ISSN 0022-3670. 9, s. 1126–1138.
• Gjevik, Bjørn & Røed, Lars Petter (1976). Storm surges along the western coast of Norway. Tellus. Series A, Dynamic meteorology and oceanography. ISSN 0280-6495. 28(2), s. 166–182. Vis sammendrag

  Storm surge situations along the western coast of Norway between 62oN and 68oN are examined. The observations show that large storm surges are caused by strong south westerly winds acting along a large section of the coast. This situation occurs when an intense low pressure center moves relatively close to the coast and in a direction nearly parallel to it. A model of surge generation by propagating wind fields acting along a straight coast is studied. Analytical solutions for the surge amplitude along the coast are obtained and discussed. The theory is applied to storm surge situations along the western coast of Norway, and it shows that the wind stress in the direction along the coast and the Coriolis force are important forces for the generation of large surges. The wind stress component normal to the coast (i.e., north westerly winds) and the changes in the atmospheric pressure contribute less to the surge.

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• Gjevik, Bjørn (2009). Flo og fjære langs kysten av Norge og Svalbard. Farleia Forlag. ISBN 978-82-998031-0-6. 351 s.
• Grue, John; Gjevik, Bjørn & Weber, Jan Erik (1996). Waves and Nonlinear Processes in Hydrodynamics. Kluwer Academic Publishers. ISBN 0-7923-4031-0. 402 s.

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• Gjevik, Bjørn (2016). Ulykken på Ona i 1670 - Kan noe liknende skje i dag? I Sanden, Jarle (Red.), Årbok 2016 Romsdalsmuseet- Naturkatastrofer. Romsdalsmuseet. ISSN 978-82-90251-94-4. s. 35–48.
• Gjevik, Bjørn & Nilsen, Steinar (2014). Beretninger om linefiske på bankene utenfor Midt-NorgeBeretninger om linefiske på bankene utenfor Midt-Norge. I Aune, Kolbjørn & Bjørkvik, Eilert (Red.), Årbok for Fosen 2014. Fosen Historielag. ISSN 978-82-90341-44-7. s. 115–140.
• Hjelmervik, Karina Bakkeløkken; Lynge, Birgit Kjoss & Gjevik, Bjørn (2013). Modelling of tides and storm surges in Theldsund channel.
• Sørensen, Mathilde B.; Bondevik, Stein & Gjevik, Bjørn (2012). Norwegian fjords sang along – observations of seiches following the 2011 Tohoku, Japan, earthquake.
• Bondevik, Stein; Sørensen, Mathilde B. & Gjevik, Bjørn (2012). Norwegian fjords sang along – observations of seiches following the 2011 Tohoku, Japan, earthquake.
• Gjevik, Bjørn (2011). Månen nær jorda 19.mars. Forskning.no. ISSN 1891-635X.
• Gjevik, Bjørn (2011). Vær, vind og sjø - fra Petter Dass til moderne forskning. I Skorpen, Knut & Severinsen, Anne (Red.), Årbok for Helgeland 2011. Helgeland Historielag. ISSN 978-82-90148-41-1. s. 10–18.
• Gjevik, Bjørn (2010). Flo og fjære langs kysten av Norge. Almanakk for Norge. ISSN 0806-5632. s. 48–51.
• Gjevik, Bjørn (2010). Flo og fjære langs norskekysten. Kysten. ISSN 0332-9550. s. 16–20.
• Gjevik, Bjørn (2010). Tidevannet - Et mangfoldig og komplekst fenomen. Fra Fysikkens Verden. ISSN 0015-9247.
• Hjelmervik, Karina Bakkeløkken; Lynge, Birgit Kjoss; Ommundsen, Atle & Gjevik, Bjørn (2009). Modelling of tides and storm surges in the Tjeldsund channel in northern Norway.
• Weber, Jan Erik H. & Gjevik, Bjørn (2008). Havnivået langs Norskekysten. Forskning.no. ISSN 1891-635X.
• Hjelmervik, Karina Bakkeløkken; Ommundsen, Atle & Gjevik, Bjørn (2007). Model simulations of tidal currents in Tjeldsundet and Ramsundet, northern Norway.
• Gjevik, Bjørn; Pedersen, Geir Kleivstul & Harbitz, Carl Bonnevie (2005). Flodbølger – kan de varsles? Aftenposten (morgenutg. : trykt utg.). ISSN 0804-3116.
• Gjevik, Bjørn (2005). Flodbølge-faren i Norge. Aftenposten (morgenutg. : trykt utg.). ISSN 0804-3116.
• Gjevik, Bjørn & Pedersen, Geir Kleivstul (2005). Flodbølger fra skred og jordskjelv. Fra Fysikkens Verden. ISSN 0015-9247. s. 4–10.
• Gjevik, Bjørn (2000). Modeller for tidevann og tidevannstrømmer langs norskekysten. Vis sammendrag

  Tidevann og tidevannsstrømmer kan beregnes ved hjelp av matematiske modeller og datamaskiner. I foredraget forklares det hvordan slike beregninger blir gjennomført. Resultatene sammenlignes med målinger langs norskekysten og visualiseres ved videoanimasjoner. Beregnet strømfelt vil i fremtiden inngå i den nye generasjon av elekroniske sjøkart og strømfelter vil kunne sees på kartmonitoren når man seiler i strømsterke farvann.

• Gjevik, Bjørn & Hareide, Daniel (2000). Ekstrem vannstandsendring og strøm i Oslofjorden. Natten mellom 3. og 4. desember 1999. Naturen. ISSN 0028-0887. s. 258–263. Vis sammendrag

  I Oslofjorden er tidevannet, altså de regelmessige skiftningene i vannstand som følge av månen og solas virkning, mindre enn 36 cm. Atmosfærisk pådrag som lufttrykkendringer og sterk vind kan enkelte ganger føre til mye større utslag enn dette. Når vannstanden endrer seg mye over forholdsvis kort tid må storevannmasser transporteres gjennom Drøbaksundet og det vil medføre meget sterk strøm i det trange sundet. Manuskript finnes på: http://www.math.uio.no/~bjorng/oslofjord/manus.pdf

• Gjevik, Bjørn; Moe, Halvard & Ommundsen, Atle (2000). Venturing into the vortex. [Radio]. Channel Four, Equinox Lethal Seas : Northlight Productions. Vis sammendrag

  The whirlpool occupies a mythical place in our consciousness. It is an oceanic phenomenon which inspires worldwide awe and terror. Every culture which witnesses this rare spectacle has its legends of monsters of the deep, seizing seafarers and dragging them to their doom. But what are the scientific facts behind the legend? Equinox ventures into the eye of the Maelstrom to capture unique footage of the world's most lethal seas, showing the whirlpool in all its mighty grandeur.

• Gjevik, Bjørn (2000). Summary and assessment of the NDP MetOcean project.
• Gjevik, Bjørn (2000). Hva vet vi om Golfstrømmen utenfor norskekysten ?
• Gjevik, Bjørn (1999). Moskstraumen; Myter Diktning og Virkelighet.
• Gjevik, Bjørn & Moe, Halvard (1999). Idealized model simulations of barotropic flow on the Catalan shelf. Vis sammendrag

  The effect of a shelf width increase on barotropic shelf edge flows and topographic shelf waves are investigated with a numerical model. The numerical experiments are carried out with flow imposed upstream, both steady and oscillatory, at the narrow shelf. A prescribed shelf edge flow gives a strong tendency for topographic steering in the transition zone. The adjustment is found to take place on a short time scale of 2-5 days set by propagating wave modes rather than by advection. Bottom friction effects do not lead to significant on-shelf leakage of the flow. Flow instability and eddy formation is found to occur, even in cases when the potential vorticity for the imposed flow does not have a local maximum on the shelf slope. The instability lead to development of anticyclonic eddies on the narrow shelf which undergo a strong non-linear adjustment at the transition zone from a narrow to a broader shelf. On the broad section of the shelf near the transition zone there is a tendency for formation of a large anticyclonic eddy. Bottom friction influences the flow instability and eddy formation in cases where the situation is marginal for flow instability and growth of eddies. Finally we have studied the current response due to a consentrated wind stress jet acting perpendicular to the coast line in the zone between the narrow and the broad shelf regions. A dipole eddy structure is found to develop with the axis tilting about 30 degrees with the axis of the wind jet and with strong current shear in the zone near the dipole axis.

• Gjevik, Bjørn; Moe, Halvard & Ommundsen, Atle (1999). Idealized model simulations of barotropic flow on the Catalan shelf. Vis sammendrag

  The effect of longshelf variation in shelf width on barotropic shelf edge flows and topographic shelf waves are investigated with a numerical model. The model topography represents a gradual transition from a narrow straight to a broader straight shelf region. It is designed primary to model the Catalan shelf on the northeastern Mediterranean coast of Spain, but the results obtained here are of general validity and will also apply to shelf flow under similar conditions elsewhere. The numerical experiments are carried out with flow imposed, both steady and oscillatory, at the upstream end of the narrow shelf region. With a prescribed shelf edge flow there is a strong tendency for topographic steering in the transition zone. The adjustment is found to take place on a short time scale of 2-5 days set by propagating wave modes rather than by advection. Bottom friction effects do not lead to significant on-shelf leakage of the flow. Flow instability and eddy formation are found to occur, even in cases where the potential vorticity for the imposed flow does not have a local maximum on the shelf slope. The instability leads to development of anticyclonic eddies on the narrow shelf which undergo strong non-linear adjustment at the transition zone from a narrow to a broader shelf. On the broad section of the shelf near the transition zone there is a tendency for formation of a large anticyclonic eddy. Bottom friction is found to influence the flow instability and the formation of eddies in cases where the flow is marginal for instability and growth of eddies. Particle tracking has been performed in order to study cross shelf mixing and transport. Finally we have studied the current response due to a concentrated wind stress jet acting perpendicular to the coast line in the transition zone between the narrow and the broad shelf regions. A dipolar eddy structure is found to develop with the axis of the dipole tilting about 30 degrees with the axis of the wind jet and with strong current shear in the zone near the dipole axis.

• Gjevik, Bjørn (1999). Effect of along shelf variation in bathymetry on shelf slope currents and tides.
• Hjelmervik, Karina Bakkeløkken; Ommundsen, Atle & Gjevik, Bjørn (2006). Modellsimuleringer av tidevannstrømmen i Tjeldsundet og Ramsundet. Universitetet i Oslo. ISSN 0809-4403.
• Hjelmervik, Karina Bakkeløkken; Ommundsen, Atle & Gjevik, Bjørn (2005). Implementation of non-linear advection terms in a high resolution tidal model. Universitetet i Oslo. ISSN 0809-4403.
• Ommundsen, Atle; Hjelmervik, Karina Bakkeløkken & Gjevik, Bjørn (2005). Tidevannstrømmen i Tjeldsund-Ramsund, 1.-3. november 2005. Forsvarets forskningsinstitutt.
• Gjevik, Bjørn & Fagerland, Morten Wang (2003). Felteori og vektoranalyse. Forelesninger og oppgaver i MEK1100. Universitetet i Oslo .
• Moe, Halvard; Gjevik, Bjørn & Ommundsen, Atle (2000). A high resolution tidal model for the coast of Møre and Trøndelag, Mid Norway. Matematisk Institutt, Universitetet i Oslo. ISSN 82-553-1236-6. Vis sammendrag

  A numerical model with grid resolution 500 m has been used to simulate tides on a section of the shelf off the coast of Møre and Trøndelag in western Norway. The model spans about 3 degrees latitude and covers a sea area of approximately 8x10^4 km^2. The fine spatial resolution resolves the important fine scale features of the bottom topography on the shelf and the complex coastline with fjords and islands. Boundary conditions at the oceanic sides of the model domain are obtained by interpolation from a larger scale tidal model covering the Nordic Seas. The semi-diurnal components M_2, S_2 and N_2 and the diurnal component K_1 are simulated. Harmonic constants for sea level are compared with observations from 28 stations. The standard deviations between the observed and modelled amplitudes and phases for the dominant semi-diurnal component, M_2, are 1.7 cm and 5.1 degrees respectively. Current fields from the model are compared with observations from stations along the pipeline from Tjeldbergodden on the coast to the oil and gas fields on the northern rim of Haltenbanken.

• Moe, Halvard; Ommundsen, Atle & Gjevik, Bjørn (2000). A high resolution tidal model for the area around The Lofoten Islands, Northern Norway. Matematisk Institutt, Universitetet i Oslo. ISSN 82-553-1237-4. Vis sammendrag

  A numerical model with grid resolution 500 m has been used to simulate tides around The Lofoten Islands in northern Norway. The model spans more than 3 degrees latitude and covers a sea area of approximately 1.2x10^5 km^2. The fine spatial resolution resolves the important fine scale features of the bottom topography on the shelf and the complex coastline with fjords and islands. Boundary conditions at the oceanic sides of the model domain are obtained by interpolation from a large scale tidal model covering the Nordic Seas. The semi-diurnal components M_2, S_2 and N_2 and the diurnal component K_1 are simulated. Harmonic constants for sea level are compared with observations from 21 stations. The best fit is found for the M_2 component with a standard deviation between the observed and modelled amplitude and phase of respectively 2.3 cm and 2.5 degrees. The standard deviation for the other smaller components ranges 1.5-2.8 cm and 5.3-16.7 degrees. Current fields from the model are compared with observations in four locations; the Moskenes sound, the Gimsøy channel, the Tjeldsund channel and the Sortland channel. Current speed is found to be in good agreement with observations. In the Sortland channel the model predicts a dominant diurnal K_1 current in agreement with observations.

• Ommundsen, Atle & Gjevik, Bjørn (2000). Scattering of tidal Kelvin waves along shelves which vary in their lengthwise direction. University of Oslo, Department of Mathematics. ISSN 82-553-1245-5. 4. Vis sammendrag

  The effect of along shelf variation in shelf width on the propagation of Kevin waves with semi-diurnal, M2, or diurnal, K1, period is studied using a numerical model. Two idealized cases are considered characterized by either a transition zone from a broad to a narrow shelf or vice versa. Simulations show that the semi-diurnal Kelvin waves adjust gradually in the transition zone to a transmitted Kelvin wave matching the downstream depth profile. The simulations of a propagating diurnal Kelvin wave show mode conversion and the development of shelf waves. This may lead to regions on the shelf with dominant diurnal currents even in cases where the sea surface amplitude of the diurnal tide is much smaller than the semi-diurnal.

• Gjevik, Bjørn (2000). Summary and assessment of the NDP MetOcean project. Norwegian Depwater Programme, Norske Shell, Stavanger.

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