Simulating or prescribing the influence of tides on the Amundsen Sea ice shelves - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Ocean Modelling Année : 2019

Simulating or prescribing the influence of tides on the Amundsen Sea ice shelves

Résumé

The representation of tides in regional ocean simulations of the Amundsen Sea enhances ice-shelf melting, with weakest effects for Pine Island and Thwaites (< +10%) and strongest effects for Dotson, Cosgrove and Abbot (> +30%). Tides increase vertical mixing throughout the water column along the continental shelf break. Diurnal tides induce topographically trapped vorticity waves along the continental shelf break, likely underpinning the tidal rectification (residual circulation) simulated in the Dotson-Getz Trough. However, the primary effect by which tides affect ice-shelf melting is the increase of ice/ocean exchanges, rather than the modification of water masses on the continental shelf. Tide-induced velocities strengthen turbulent heat fluxes at the ice/ocean interface, thereby increasing melt rates. Approximately a third of this effect is counterbalanced by the resulting release of cold melt water that reduces melt downstream along the meltwater flow. The relatively weak tideinduced melting underneath Pine Island and Thwaites could be partly related to their particularly thick water column, which limits the presence of quarter wavelength tidal resonance. No sensitivity to the position of Pine Island and Thwaites with respect to the M2 critical latitude is found. We refine and evaluate existing methodologies to prescribe the effect of tides on ice-shelf melt rates in ocean models that do not explicitely include tidal forcing. The best results are obtained by prescribing spatially-dependent tidal top-boundary-layer velocities in the melt equations. These velocities can be approximated as a linear function of existing barotropic tidal solutions. A correction factor needs to be applied to account for the additional melt-induced circulation associated with tides and to reproduce the relative importance of dynamical and thermodynamical processes.
Fichier principal
Vignette du fichier
jourdain_OceMod_2018_revised_2.pdf (80.2 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-03334733 , version 1 (06-10-2021)

Identifiants

Citer

Nicolas C Jourdain, Jean-Marc Molines, Julien Le Sommer, Pierre Mathiot, Jérôme Chanut, et al.. Simulating or prescribing the influence of tides on the Amundsen Sea ice shelves. Ocean Modelling, 2019, 133, pp.44 - 55. ⟨10.1016/j.ocemod.2018.11.001⟩. ⟨hal-03334733⟩
128 Consultations
25 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More