Papers by Maarten Buijsman
Ocean Science Discussions, 2015
The Brazilian continental shelf break in the tropical Atlantic Ocean off the Amazon River mouth i... more The Brazilian continental shelf break in the tropical Atlantic Ocean off the Amazon River mouth is amongst the most energetic regions in the world for generation of internal tides (Baines, 1982). Since the early 1980s there have been in situ observations of Internal Solitary Waves (ISWs) near the North Equatorial Counter Current (NECC) off the Brazilian continental shelf, where localized surface velocity pulses of up to 2 m/s have been documented (e.g. . Despite these early efforts, the region remained largely unexplored until recently. Here we present a first account of the coherence crest-lengths, propagation characteristics and seasonal variability of ISWs on and off the shelf, based on Synthetic Aperture Radar (SAR) images. Available ENVISAT ASAR scenes (29 in total), and additional ERS-1/2 SAR, TerraSAR-X and RADARSAT images of the region of the tropical Atlantic Ocean comprising the geographic coordinates [40°-50° W, 0°-8° N] have been examined. The SAR image analysis revealed the following main results: 1) The ISW signatures, whose coherence crest-lengths can exceed 200 km, are first detected near the southern edge of the countercurrent and intensify on the northern edge of the NECC; 2) In October, there is a strong refraction/ advection of ISWs towards the east, as they enter the influence of the NECC (in between 4° and 5° N); 3) Some on-shelf regions are prone to intense ISW signatures in the SAR, which are believed to be associated with intricate bottomtopography.
Internal waves on the upstream side of a large sill of the Mascarene Ridge: a comprehensive view of their generation mechanisms and evolution
Deep Sea Research Part I: Oceanographic Research Papers, 2015
The evolution of Mode-2 nonlinear internal waves over the northern Heng-Chun ridge south of Taiwan
Nonlinear Processes in Geophysics Discussions, 2015
ABSTRACT Two research cruises were conducted from the R/V OCEAN RESEARCHER 3 during 5–16 August 2... more ABSTRACT Two research cruises were conducted from the R/V OCEAN RESEARCHER 3 during 5–16 August 2011 to study the generation of high-frequency nonlinear internal waves (NLIW) over the northern Heng-Chun Ridge south of Taiwan. The primary study site, centered near 21°34' N, 120°54' E, was on top of a smaller ridge about 15 km wide by 400 m high atop the primary ridge, with a sill depth of approximately 600 m. The bottom slope was steep over both sides of the ridge, supercritical with respect to both diurnal and semidiurnal tides. The key result of the experiments is that a profusion of mode-2 NLIW were observed by all the sensors. Some of the waves were solitary while others had as many as seven evenly-spaced waves per packet. The waves all exhibited classic mode-2 velocity structure with a core near 150–200 m and opposing velocities in the layers above and below. At least two and possibly three most common propagation directions emerged from the analysis, suggesting multiple generation sites near the east side of the ridge. The turbulent dissipation due to overturns in the wave cores was very high at order 10−4–10−3 W kg−1. The energy budget suggests that the waves cannot persist very far from the ridge and likely do not contribute to the South China Sea transbasin wave phenomenon.
Development of Parameterizations of Tidal Mixing Using Numerical Process Studies
Modeling Semidiurnal Internal Tide Variability in the Southern California Bight
Journal of Physical Oceanography, 2012
Historical Sediment Budget Study
Impact of parameterized internal wave drag on the semidiurnal energy balance in a global ocean circulation model
Journal of Physical Oceanography, 2016
Corrigendum: The formation and fate of internal waves in the South China Sea
Nature, Jan 18, 2015
Two field experiments on the ebb-tidal delta and adjacent beaches near Grays Harbor, Washington U... more Two field experiments on the ebb-tidal delta and adjacent beaches near Grays Harbor, Washington USA provide detailed information about bed sediments, waves, currents, suspended-sediment concentrations, and sea-bed change for the calibration and verification of numerical models of sediment transport and morphology change. For the first time, process and nearshore bottom change measurements are being coupled along the high-energy dissipative beaches typical of the U.S. Pacific Northwest. The experiments successfully capture the transition between low-energy beach-building conditions typical of summer and the high-energy erosive conditions of winter (Fall 1999 experiment), as well as the spring transition back to progradational conditions (Spring 2001 experiment).
Morphodynamics of a tidal lagoon and the adjacent coast
Indirect evidence for substantial damping of low-mode internal tides in the open ocean
Journal of Geophysical Research: Oceans, 2015
Nature, Jan 7, 2015
Internal gravity waves, the subsurface analogue of the familiar surface gravity waves that break ... more Internal gravity waves, the subsurface analogue of the familiar surface gravity waves that break on beaches, are ubiquitous in the ocean. Because of their strong vertical and horizontal currents, and the turbulent mixing caused by their breaking, they affect a panoply of ocean processes, such as the supply of nutrients for photosynthesis, sediment and pollutant transport and acoustic transmission; they also pose hazards for man-made structures in the ocean. Generated primarily by the wind and the tides, internal waves can travel thousands of kilometres from their sources before breaking, making it challenging to observe them and to include them in numerical climate models, which are sensitive to their effects. For over a decade, studies have targeted the South China Sea, where the oceans' most powerful known internal waves are generated in the Luzon Strait and steepen dramatically as they propagate west. Confusion has persisted regarding their mechanism of generation, variabilit...
Journal of Physical Oceanography, 2015
Luzon Strait is the generation region for strong internal tides that radiate westward into the So... more Luzon Strait is the generation region for strong internal tides that radiate westward into the South China Sea and eastward into the western Pacific.
Sensitivity of Shoreline Change Predictions to Wave Climate Variability along the Southwest Washington Coast, USA
Coastal Dynamics '01, 2001
A processes‐based shoreline change model is applied to simulate historical shoreline behaviour an... more A processes‐based shoreline change model is applied to simulate historical shoreline behaviour and predict future change along a 40‐km stretch of coast in the US Pacific Northwest. The sensitivity of the modeled shoreline change to different schematizations of the wave climatology is ...
Shoreface Sand Supply to Beaches
Coastal Engineering 2000, 2001
Shoreface Sand Supply to Beaches. [ASCE Conference Proceedings 276, 195 (2000)]. Peter J. Cowell,... more Shoreface Sand Supply to Beaches. [ASCE Conference Proceedings 276, 195 (2000)]. Peter J. Cowell, Marcel JF Stive, Peter S. Roy, George M. Kaminsky, Maarten C. Buijsman, Bruce G. Thom, L. Don Wright. Abstract. The possibility ...
Predicting Shoreline Change at Decadal Scale in the Pacific Northwest, USA
Coastal Engineering 2000, 2001
This paper presents the approach taken to model and predict decadal scale shoreline change in the... more This paper presents the approach taken to model and predict decadal scale shoreline change in the Columbia River littoral cell along the coast of southwest Washington and northwest Oregon. This work is a principal component of the Southwest Washington Coastal ...
For the last several thousand years the Columbia River has supplied sand to nearby bays, coastal ... more For the last several thousand years the Columbia River has supplied sand to nearby bays, coastal dunes, the continental shelf, and the continental slope and submarine canyons and fans. By quantifying the amount of sand that occupies these environments, we will gain a better understanding of the Columbia River dispersal system. We can use this insight to better predict the
Coastal Evolution and Sediment Budget at the Mouth of the Columbia River, USA
Coastal Dynamics '01, 2001
Ocean Modelling, 2015
A global tuning experiment for the semidiurnal tide is performed with a barotropic model. The mod... more A global tuning experiment for the semidiurnal tide is performed with a barotropic model. The model is forced with the M 2 equilibrium tide and accounts for the self-attraction and loading (SAL) term. In addition to a quadratic drag, various linear internal wave drag terms adjusted by a scale factor of Oð1Þ are applied. The drag terms include the original Nycander (2005) tensor scheme, the Nycander tensor scheme reduced at supercritical slopes, and their scalar sisters, a Nycander scalar scheme computed for additional abyssal hill roughness, and the Jayne and St. Laurent (2001) scalar scheme. The Nycander scheme does not have a tunable parameter, but to obtain the best tidal solutions, it is demonstrated that some tuning is unavoidable. It is shown that the scalar Nycander schemes yield slightly lower root-mean square (RMS) elevation errors vs. the data-assimilative TPXO tide model than the tensor schemes. Although the simulation with the optimally tuned original Nycander scalar yields dissipation rates close to TPXO, the RMS error is among the highest. The RMS error is lowered for the reduced schemes, which place relatively more dissipation in deeper water. The inclusion of abyssal hill roughness improves the regional agreement with TPXO dissipation rates, without changing the RMS errors. It is difficult to have each ocean basin optimally tuned with the application of a constant scale factor. The relatively high RMS error in the Atlantic Ocean is reduced with a spatially varying scale factor with a larger value in the Atlantic. Our best global mean RMS error of 4.4 cm for areas deeper than 1000 m and equatorward of 66°is among the lowest obtained in a forward barotropic tide model.
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Papers by Maarten Buijsman