A Stratigraphic Soil Model for Coastal Morphodynamics

Sediment Transport and Morphodynamic

The impact of a wave farm on large scale sediment transport

This study investigates the interactions of waves and tides at a wave farm in the southwest of England, in particular their effects on radiation stress, bottom stress, and consequently on the sediment transport and the coast adjacent to the wave-farm (the Wave Hub). In this study, an integrated complex numerical modelling system is setup at the Wave Hub site and is used to compute the wave and current fields by taking into account the wave-current interaction, as well as the sediment transport. Results show that tidal elevation and tidal currents have a significant effect on the wave height and direction predictions; tidal forcing and wind waves have a significant effect on the bed shear-stress, relevant to sediment transport; waves via radiation stresses have an important effect on the longshore and cross-shore velocity components, particularly during the spring tides. Waves can impact on bottom boundary layer and mixing in the water column. The results highlight the importance of the interactions between waves and tides when modelling coastal morphology with presence of wave energy devices

Integrated Numerical Models in Coastal Areas: An Example of Their Application in the North Adriatic Sea

Recent decades have witnessed considerable developments in the field of integrated numerical models used for simulating dynamic processes in coastal areas, that can now provide quantitative support to decision makers for questions such as erosion and coastal vulnerability. Improvements in various theoretical formulations and an on-going increase in computing power (alongside the growing availability of long-term observations and numerical output from meteorological and sea-state models) allow the implementation of high-resolution and long-term applications.However, the efficient use of these numerical tools is a function of their capacity to describe a variety of physical processes that are ‘integrated’ amongst themselves correctly. Indeed, from the air-sea interface to the turbulent mixing of water masses and the water-sediment interaction, integrated numerical modelling has to face a series of scientific and practical challenges still open. Examples include the non-linear interaction of waves and currents, the problem of turbulence, the modelling of resuspension and sediment-transport processes, the role of longperiod waves in generating beach and dune erosion. Dealing with these using numerical models is necessary for a variety of reasons, from protecting the coast to search-and-rescue activities and support for marine construction work of all types

Efeito do Acoplamento dos Modelos numéricos Roms-WRF na camada Limite Planetária – Um Estudo de Caso sobre a Confluência Brasil-Malvias

The planetary boundary layer (PBL) region of the atmosphere, is strongly influencied by the interaction with the surface. This paper studied the effect on PBL over the ocean using a coupled ocean-atmosphere-wave-sediment transport numerical model (COAWST). It was done two experiments, one with COAWST and another with atmospheric model WRF.A camada limite planetária (CLP), região da atmosfera na qual habitamos, é fortemente regida pela interação com a superfície terrestre. Neste trabalho foi estudado o efeito na CLP da confluência Brasil-Malvinas utilizando o COAWST, um modelo numérico acoplado oceano-atmosfera-ondas-transporte de sedimentos. Para isso foi realizado dois experimentos, um somente com o modelo COAWST e outro somente o modelo atmosférico WRF. Foi notada uma intensificação nos gradientes horizontais de vento e theta, e no cisalhamento vertical do vento. Estas alterações podem levar a instabilidades afetando níveis mais altos da atmosfera.

New developments and validations for the 3D sediment transport modelling within the Telemac Modelling System

Water Qualit

Numerical Model of Geochronological Tracers for Deposition and Reworking Applied to the Mississippi Subaqueous Delta

Measurements of naturally occurring, short-lived radioisotopes from sediment cores on the Mississippi subaqueous delta have been used to infer event bed characteristics such as depositional thicknesses and accumulation rates. Specifically, the presence of Beryllium-7 (Be-7) indicates recent riverine-derived terrestrial sediment deposition; while Thorium-234 (Th-234) provides evidence of recent suspension in marine waters. Sediment transport models typically represent coastal flood and storm deposition via estimated grain size patterns and deposit thicknesses, however, and do not directly calculate radioisotope activities and profiles, which leads to a disconnect between the numerical model and field observations. Here, observed radioisotopic profiles from the Mississippi subaqueous delta cores were directly related to a numerical model that represented resuspension and deposition using a new approach to account for the behavior of short-lived radioisotopes. Appropriate selection of parameters such as the bioditfusion coefficient, sediment accumulation rate, and radioisotopic source terms enabled a good match between the modeled and observed cores. Comparisons of modelled profiles with geochronological analytical models that estimate accumulation rate and flood layer thickness revealed potential avenues for refining these tools, and highlight the importance of constraining the biodiffusion coefficient

Modeling of storm surges and wave heights during few cyclones over Bay of Bengal using uncoupled and coupled (ADCIRC+SWAN) models

867-878In this study, the uncoupled (ADCIRC) and a tightly-coupled SWAN (Simulating Waves at Near shore) + ADCIR (Advance circulation Model) models are used to estimate the storm surge heights along the east coast of India. four cyclones over the Bay of Bengal during 2013, viz; Mahasen ( May 10-17 ), Phailin (October 8-14 ), Helen (November 19-23) and Lehar (November 23-28),. Due to finite element nature of ADCIRC, the mesh (grid) structure was having variable spatial resolution with higher resolution (~5Km) near to the coast and 50 km offshore. The validation of simulated surges from both stand alone and coupled configurations was carried out using observations from tide gauges .The simulated wave heights were validated using observations from Ka-band Altimeter onboard SARAL(Satellite with ARgos and ALtiKa). It is found that the coupled model (ADCIRC+SWAN) performed well compared with the uncoupled model, in predicting the storm surges. The simulated maximum Water level for uncoupled (ADCIRC only) run that considers the astronomical and meteorological forcing was about 2.3 m, at Gopalpur coast (landfall point). The coupled model that considers additional wave radiation stress provides the maximum water level elevation as 3.0 m at the above location. The observed surge height close to this location was 2.9 m. The significant wave heights (SWH) estimated by the models are compared with the SARAL Altika data. More than 12000 observations are used for comparison, It is found that the correlation between the estimated and observed values of SWHs were high and significant in all the four cyclones and the highest correlation of 0.67 was observed in case of Lehar</em

Gelo marinho Antártico e a trajetória de ciclones sobre o oceano Atlântico do sul

Cyclones play an important role in the general circulation of the atmosphere, enabling the southern transport of heat, humidity and surplus moment from low latitudes to highlatitudes. In the South Atlantic, the most favorable areas for cyclone formation are close to the east coast of South America (30 ° S to 45 ° S) and the Antarctic Peninsula. One of the factors that favor the formation of cyclogenesis on the east coast of South America is the temperature contrast between the South Atlantic Oceanwith the surface air layer. Whereas cyclogenesis near the Antarctic Peninsula may be associated with pre-existing baroclinic instabilities at higher levels of the atmosphere. The objective of this work is to investigate the role of the Antarctic Peninsula in the behavior of extratropical cyclones thatact on South America and adjacent oceans. For this, the TRACK algorithm was applied to track cyclones. The ocean-atmosphere interaction will be investigated through the ocean-atmosphere mode of the COAWST coupled model. The execution of TRACK proved to be satisfactory, since the results found corroborate with the literature of the region.Os ciclones desempenham um papel importante na circulação geral da atmosfera, possibilitando os transportes meridionais de calor, umidade e momento excedentes das baixas latitudes para altas latitudes. No Atlântico Sul as áreas mais favoráveis para a formação de ciclones são próximo à costa leste da América do Sul (30°S a 45°S) e Península Antártica. Um dos fatores que favorecem a formação da ciclogênese na costa leste da América do Sul é o contraste de temperatura entre o oceano Atlântico Sul com a camada de ar superficial. Enquanto que a ciclogênese próxima à Península Antártica pode estar associada a instabilidades baroclínicas pré existentes em níveis mais altos da atmosfera. O objetivo deste trabalho é investigar qual o papel da Península Antártica no comportamento dos ciclones extratropicais que atuam sobre a América do sul e oceanos adjacentes. Para tal, foi aplicado o algoritmo TRACK para rastreamento dos ciclones. A interação oceano-atmosfera será investigada por meio do modo oceano-atmosfera do modelo acoplado COAWST. A execução do TRACK se mostrou satisfatória, uma vez que os resultados encontrados corroboram com a literatura da região