Journal Sciences News
Urologic Oncology: Seminars and Original Investigations
May 2018
Model-based assessment of a Northwestern Tropical Pacific moored array to monitor intraseasonal variability
Publication date: June 2018
Source:Ocean Modelling, Volume 126 Author(s): Danian Liu, Jiang Zhu, Yeqiang Shu, Dongxiao Wang, Weiqiang Wang, Shuqun Cai The Northwestern Tropical Pacific Ocean (NWTPO) moorings observing system, including 15 moorings, was established in 2013 to provide velocity profile data. Observing system simulation experiments (OSSEs) were carried out to assess the ability of the observation system to monitor intraseasonal variability in a pilot study, where ideal “mooring-observed” velocity was assimilated using Ensemble Optimal Interpolation (EnOI) based on the Regional Oceanic Modeling System (ROMS). Because errors between the control and “nature” runs have a mesoscale structure, a random ensemble derived from 20–90-day bandpass-filtered nine-year model outputs is proved to be more appropriate for the NWTPO mooring array assimilation than a random ensemble derived from a 30-day running mean. The simulation of the intraseasonal currents in the North Equatorial Current (NEC), North Equatorial Countercurrent (NECC), and Equatorial Undercurrent (EUC) areas can be improved by assimilating velocity profiles using a 20–90-day bandpass-filtered ensemble. The root mean square errors (RMSEs) of the intraseasonal zonal (U) and meridional velocity (V) above 500
May 2018
Editorial Board
Publication date: May 2018
Source:Ocean Modelling, Volume 125

May 2018
The importance of modeling nonhydrostatic processes for dense water reproduction in the Southern Adriatic Sea
Publication date: May 2018
Source:Ocean Modelling, Volume 125 Author(s): Debora Bellafiore, William J. McKiver, Christian Ferrarin, Georg Umgiesser Dense water (DW) formation commonly occurs in the shallow Northern Adriatic Sea during winter outbreaks, when there is a combination of the cooling of surface waters by the winds and high salinity as a result of reduced river inputs. These DWs subsequently propagate southwards over a period of weeks/months, eventually arriving in the Southern Adriatic Sea. The investigation is based on a new nonhydrostatic (NH) formulation of the 3D finite element model SHYFEM that is validated for a number of theoretical test cases. Subsequently this model is used to simulate, through high-resolution numerical simulations, an extreme DW event that occurred in the Adriatic Sea in 2012. We perform both hydrostatic (HY) and NH simulations in order to explicitly see the impact of NH processes on the DW dynamics. The modeled results are compared to observations collected in the field campaign of March–April 2012 in the Southern Adriatic Sea. The NH run correctly reproduces the across isobath bottom-trapped gravity current characterizing the canyon DW pathways. It also more accurately captures the frequency and intensity of dense water cascading pulsing events, as the inclusion of NH processes produces stronger currents with different DW mixing characteristics. Finally, the NH run simulates internal gravity waves (IGW), generated during the cascading at the edge of the canyon, which propagate downslope. This IGW activity is not captured in the HY case.
May 2018
A parameterization of the passive layer of a quasigeostrophic flow in a continuously-stratified ocean
Publication date: May 2018
Source:Ocean Modelling, Volume 125 Author(s): E.S. Benilov This paper examines quasigeostrophic flows in an ocean that can be subdivided into an upper active layer (AL) and a lower passive layer (PL), with the flow and density stratification mainly confined to the former. Under this assumption, an asymptotic model is derived parameterizing the effect of the PL on the AL. The model depends only on the PL’s depth, whereas its V
May 2018
Representing grounding line migration in synchronous coupling between a marine ice sheet model and a z-coordinate ocean model
Publication date: May 2018
Source:Ocean Modelling, Volume 125 Author(s): D.N. Goldberg, K. Snow, P. Holland, J.R. Jordan, J.-M. Campin, P. Heimbach, R. Arthern, A. Jenkins Synchronous coupling is developed between an ice sheet model and a z-coordinate ocean model (the MITgcm). A previously-developed scheme to allow continuous vertical movement of the ice-ocean interface of a floating ice shelf (“vertical coupling”) is built upon to allow continuous movement of the grounding line, or point of floatation of the ice sheet (“horizontal coupling”). Horizontal coupling is implemented through the maintenance of a thin layer of ocean (
May 2018
A discontinuous Galerkin approach for conservative modeling of fully nonlinear and weakly dispersive wave transformations
Publication date: May 2018
Source:Ocean Modelling, Volume 125 Author(s): Mohammad Kazem Sharifian, Georges Kesserwani, Yousef Hassanzadeh This work extends a robust second-order Runge–Kutta Discontinuous Galerkin (RKDG2) method to solve the fully nonlinear and weakly dispersive flows, within a scope to simultaneously address accuracy, conservativeness, cost-efficiency and practical needs. The mathematical model governing such flows is based on a variant form of the Green–Naghdi (GN) equations decomposed as a hyperbolic shallow water system with an elliptic source term. Practical features of relevance (i.e. conservative modeling over irregular terrain with wetting and drying and local slope limiting) have been restored from an RKDG2 solver to the Nonlinear Shallow Water (NSW) equations, alongside new considerations to integrate elliptic source terms (i.e. via a fourth-order local discretization of the topography) and to enable local capturing of breaking waves (i.e. via adding a detector for switching off the dispersive terms). Numerical results are presented, demonstrating the overall capability of the proposed approach in achieving realistic prediction of nearshore wave processes involving both nonlinearity and dispersion effects within a single model.
May 2018
The numerics of hydrostatic structured-grid coastal ocean models: State of the art and future perspectives
Publication date: May 2018
Source:Ocean Modelling, Volume 125 Author(s): Knut Klingbeil, Florian Lemari
Available online 18 April 2018
Some effects of horizontal discretization on linear baroclinic and symmetric instabilities
Publication date: May 2018
Source:Ocean Modelling, Volume 125 Author(s): William Barham, Scott Bachman, Ian Grooms The effects of horizontal discretization on linear baroclinic and symmetric instabilities are investigated by analyzing the behavior of the hydrostatic Eady problem in ocean models on the B and C grids. On the C grid a spurious baroclinic instability appears at small wavelengths. This instability does not disappear as the grid scale decreases; instead, it simply moves to smaller horizontal scales. The peak growth rate of the spurious instability is independent of the grid scale as the latter decreases. It is equal to $c f / Ri$ where Ri is the balanced Richardson number, f is the Coriolis parameter, and c is a nondimensional constant that depends on the Richardson number. As the Richardson number increases c increases towards an upper bound of approximately 1/2; for large Richardson numbers the spurious instability is faster than the Eady instability. To suppress the spurious instability it is recommended to use fourth-order centered tracer advection along with biharmonic viscosity and diffusion with coefficients