The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform
Dano Roelvink - One of the best experts on this subject based on the ideXlab platform.
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do salt marshes survive sea level rise modelling Wave Action morphodynamics and vegetation dynamics
Environmental Modelling and Software, 2018Co-Authors: U S N Best, M Van Der Wegen, J Dijkstra, Pim Wilhelmus Johannes Maria Willemsen, Bastiaan Wijnand Borsje, Dano RoelvinkAbstract:This paper aims to fundamentally assess the resilience of salt marsh-mudflat systems under sea level rise. We applied an open-source schematized 2D area model (Delft3D) that couples intertidal flow, Wave-Action, sediment transport, geomorphological development with a population dynamics approach including temporal and spatial growth of vegetation and bio-accumulation. Wave-Action maintains a high sediment concentration on the mudflat while the tidal motion transports the sediments within the vegetated marsh areas during flood. The marsh-mudflat system attained dynamic equilibrium within 120 years. Sediment deposition and bio-accumulation within the marsh make the system initially resilient to sea level rise scenarios. However, after 50–60 years the marsh system starts to drown with vegetated-levees being the last surviving features. Biomass accumulation and sediment supply are critical determinants for the marsh drowning rate and survival. Our model methodology can be applied to assess the resilience of vegetated coast lines and combined engineering solutions for long-term sustainability.
Victor I Shrira - One of the best experts on this subject based on the ideXlab platform.
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explicit Wave Action conservation for water Waves on vertically sheared flows
Ocean Modelling, 2017Co-Authors: Brenda Quinn, Yaron Toledo, Victor I ShriraAbstract:Abstract This paper addresses a major shortcoming of the current generation of Wave models, namely their inability to describe Wave propagation upon ambient currents with vertical shear. The Wave Action conservation equation (WAE) for linear Waves propagating in horizontally inhomogeneous vertically-sheared currents is derived following Voronovich (1976). The resulting WAE specifies conservation of a certain depth-averaged quantity, the Wave Action, a product of the Wave amplitude squared, eigenfunctions and functions of the eigenvalues of the boundary value problem for water Waves upon a vertically sheared current. The formulation of the WAE is made explicit using known asymptotic solutions of the boundary value problem which exploit the smallness of the current magnitude compared to the Wave phase velocity and/or its vertical shear and curvature; the adopted approximations are shown to be sufficient for most of the conceivable applications. In the limit of vanishing current shear, the new formulation reduces to that of Bretherton and Garrett (1968) without shear and the invariant is calculated with the current magnitude taken at the free surface. It is shown that in realistic oceanic conditions, the neglect of the vertical structure of the currents in Wave modelling which is currently universal might lead to significant errors in Wave amplitude. The new WAE which takes into account the vertical shear can be better coupled to modern circulation models which resolve the three-dimensional structure of the uppermost layer of the ocean.
N M Shapiro - One of the best experts on this subject based on the ideXlab platform.
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global oceanic microseism sources as seen by seismic arrays and predicted by Wave Action models
Geochemistry Geophysics Geosystems, 2012Co-Authors: Gregor Hillers, Nicholas E Graham, Michel Campillo, S Kedar, M Landes, N M ShapiroAbstract:We analyze global microseism excitation patterns between July 2000 and June 2001. Seismological observations are compared with modeling results to isolate robust activity features of relevant source processes. First, we use observations of microseism source locations estimated by Landes et al. (2010) based on array processing of ambient noise correlations. Second, we construct synthetic activity patterns by coupling sea state estimates derived from Wave Action models to the excitation theory for microseisms. The overall spatiotemporal evolution of both estimates is characterized by a seasonal character that is associated with strong activity during winter months. The distribution of landmass causes seasonal changes on the Northern Hemisphere (NH) to exceed the variability on the Southern Hemisphere (SH). Our systematic comparison of the two estimates reveals significant microseism excitation along coastlines and in the open ocean. Since coastal reflections are not accounted for in the modeling approach, the consistent mismatch between near-coastal observations and predictions suggests that relevant microseism energy arriving at the networks is generated in these areas. Simultaneously, systematic coincidence away from coastlines verifies the open ocean generation hypothesis. These conclusions are universal and robust with respect to the seismic network locations on the NH. The spatially homogeneous resolution of our synthetics provides a valuable resource for the assessment of the global microseism weather. Similar to previously identified hot spot areas in the North Atlantic, the modeled distributions hypothesize regions of strong localized activity on the SH, which are only partially confirmed by the analyzed data sets.
U S N Best - One of the best experts on this subject based on the ideXlab platform.
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do salt marshes survive sea level rise modelling Wave Action morphodynamics and vegetation dynamics
Environmental Modelling and Software, 2018Co-Authors: U S N Best, M Van Der Wegen, J Dijkstra, Pim Wilhelmus Johannes Maria Willemsen, Bastiaan Wijnand Borsje, Dano RoelvinkAbstract:This paper aims to fundamentally assess the resilience of salt marsh-mudflat systems under sea level rise. We applied an open-source schematized 2D area model (Delft3D) that couples intertidal flow, Wave-Action, sediment transport, geomorphological development with a population dynamics approach including temporal and spatial growth of vegetation and bio-accumulation. Wave-Action maintains a high sediment concentration on the mudflat while the tidal motion transports the sediments within the vegetated marsh areas during flood. The marsh-mudflat system attained dynamic equilibrium within 120 years. Sediment deposition and bio-accumulation within the marsh make the system initially resilient to sea level rise scenarios. However, after 50–60 years the marsh system starts to drown with vegetated-levees being the last surviving features. Biomass accumulation and sediment supply are critical determinants for the marsh drowning rate and survival. Our model methodology can be applied to assess the resilience of vegetated coast lines and combined engineering solutions for long-term sustainability.
Brenda Quinn - One of the best experts on this subject based on the ideXlab platform.
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explicit Wave Action conservation for water Waves on vertically sheared flows
Ocean Modelling, 2017Co-Authors: Brenda Quinn, Yaron Toledo, Victor I ShriraAbstract:Abstract This paper addresses a major shortcoming of the current generation of Wave models, namely their inability to describe Wave propagation upon ambient currents with vertical shear. The Wave Action conservation equation (WAE) for linear Waves propagating in horizontally inhomogeneous vertically-sheared currents is derived following Voronovich (1976). The resulting WAE specifies conservation of a certain depth-averaged quantity, the Wave Action, a product of the Wave amplitude squared, eigenfunctions and functions of the eigenvalues of the boundary value problem for water Waves upon a vertically sheared current. The formulation of the WAE is made explicit using known asymptotic solutions of the boundary value problem which exploit the smallness of the current magnitude compared to the Wave phase velocity and/or its vertical shear and curvature; the adopted approximations are shown to be sufficient for most of the conceivable applications. In the limit of vanishing current shear, the new formulation reduces to that of Bretherton and Garrett (1968) without shear and the invariant is calculated with the current magnitude taken at the free surface. It is shown that in realistic oceanic conditions, the neglect of the vertical structure of the currents in Wave modelling which is currently universal might lead to significant errors in Wave amplitude. The new WAE which takes into account the vertical shear can be better coupled to modern circulation models which resolve the three-dimensional structure of the uppermost layer of the ocean.
