A non-hydrostatic non-Boussinesq algorithm for free-surface ocean modelling

Auclair, Francis; Bordois, Lucie; Dossmann, Yvan; Duhaut, Thomas; Paci, Alexandre; Ulses, Caroline; Nguyen, Cong Tu

doi:10.1016/j.ocemod.2018.07.011

Cited by 27 publications

(34 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We use outputs of realistic numerical simulations that were carried out for the Mediterranean Sea using the CROCO numerical model (http://www.croco-ocean.org). We refer to Shchepetkin and McWilliams (2005) and Debreu et al (2012) as well as to Auclair et al (2018) for details regarding the CROCO inherited numerics from ROMS, its barotropic time-stepping setup and its solver. The simulation under investigation, CROCO-MED60v40-2015, was forced at the ocean top with ARPEGE wind forcing, thanks to the classical bulk COARE formula (Fairall et al, 2003) that takes into account the wind stress acting on the ocean surface as…”

Section: Croco Ocean Modelmentioning

confidence: 99%

Three-Dimensional Evolution of Mesoscale Anticyclones in the Lee of Crete

et al. 2020

View full text Add to dashboard Cite

Motivated by the recurrent formation of mesoscale anticyclones in the southeast of Crete, we investigated with a high resolution model the response of the ocean to orographic wind jets driven by the Cretean mountain range. As shown in the dynamical process study of Ioannou et al. (2020) which uses a simplified shallow-water model, we confirm here, using the CROCO (Coastal and Regional Ocean COmmunity) model, that the main oceanic response to the Etesian wind forcing is the formation of mesoscale anticyclones. Moreover, we found that the intensity of the wind-induced Ekman pumping acting on the eddies, once they are formed, modulates their intensity. Among the various coastal anticyclones formed during summer and fall 2015, only one of them will correspond to a long lived structure (M_IE15) which is similar to the Ierapetra Eddy detected in 2015 (O_IE15) on the AVISO/DUACS products. Thanks to the DYNED-Atlas data base, we were able to perform a quantitative comparison of the vertical structure of such long-lived anticyclone between the numerical model and the in-situ measurements of the various Argo profilers trapped inside the eddy core. Even without assimilation or any nudging, the numerical model was able to reproduce correctly the formation period, the seasonal evolution and the vertical structure of the O_IE15. The main discrepancy between the model and the altimetry observations is the dynamical intensity of the anticyclone. The characteristic eddy velocity derived from the AVISO/DUACS product for the O_IE15 is much lower than in the numerical model. This is probably due to the spatio temporal interpolation of the AVISO/DUACS altimetry products. More surprisingly, several coastal anticyclones were also formed in the model in the lee of Crete area during summer 2015 when the Etesian winds reach strong values. However, these coastal anticyclones respond differently to the wind forcing since they remain close to the coast, in shallow-waters, unlike the M_IE15 which propagates offshore in deep water. The impact of the bottom friction or the coastal dissipation seems to limit the wind amplification of these coastal anticyclones.

show abstract

Section: Croco Ocean Modelmentioning

confidence: 99%

Three-Dimensional Evolution of Mesoscale Anticyclones in the Lee of Crete

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Another possibility to consistently add non-hydrostatic effects, while avoiding the costly direct solution of a 3D Poisson equation for the pressure, is to relax both the hydrostatic and Boussinesq assumptions (Auclair et al, 2016). Since relaxing the Boussinesq assumption reintroduces the acoustic waves, an acoustic mode must be considered on top of the internal and external modes.…”

Section: Non-hydrostatic and Boussinesq Assumptionmentioning

confidence: 99%

The numerics of hydrostatic structured-grid coastal ocean models: State of the art and future perspectives

et al. 2018

View full text Add to dashboard Cite

The state of the art of the numerics of hydrostatic structured-grid coastal ocean models is reviewed here. First, some fundamental differences in the hydrodynamics of the coastal ocean, such as the large surface elevation variation compared to the mean water depth, are contrasted against large scale ocean dynamics. Then the hydrodynamic equations as they are used in coastal ocean models as well as in large scale ocean models are presented, including parameterisations for turbulent transports. As steps towards discretisation, coordinate transformations and spatial discretisations based on a finite-volume approach are discussed with focus on the specific requirements for coastal ocean models. As in large scale ocean models, splitting of internal and external modes is essential also for coastal ocean models, but specific care is needed when drying & flooding of intertidal flats is included. As one obvious characteristic of coastal ocean models, open boundaries occur and need to be treated in a way that correct model forcing from outside is transmitted to the model domain without reflecting waves from the inside. Here, also new developments in two-way nesting are presented. Single processes such as internal inertia-gravity waves, advection and turbulence closure models are discussed with focus on the coastal scales. Some overview on existing hydrostatic structured-grid coastal ocean models is given, including their extensions towards non-hydrostatic models. Finally, an outlook on future perspectives is made.

show abstract

“…The numerical simulations presented in this paper were performed using the non-hydrostatic, non-Boussinesq version of the Coastal and Regional Ocean Community model (CROCO). This model was adapted from the Regional Ocean Modeling System (ROMS, Shchepetkin & McWilliams 2005) to include non-hydrostatic and compressible effects (Auclair et al 2018). While numerical simulations of KH instabilities are often considered in a periodic domain with free-slip rigid lid conditions for the upper and lower boundaries (e.g.…”

Section: Numerical Model and Flow Configurationmentioning

confidence: 99%