The influence of ice melange on fjord seiches
Abstract:We compute the eigenmodes (seiches) of the barotropic and baroclinic hydrodynamic equations for an idealized fjord having length and depth scales similar to those of Ilulissat Icefjord, Greenland, into which Jakobshavn Isbrae (also known as Sermeq Kujalleq) discharges. The purpose of the computation is to determine the fjord's seiche behavior when forced by iceberg calving, capsize and melange movement. Poorly constrained bathymetry and stratification details are an acknowledged obstacle. We are, nevertheless, able to make general statements about the spectra of external and internal seiches using numerical simulations of ideal one-dimensional channel geometry. Of particular significance in our computation is the role of weakly coupled ice melange, which we idealize as a simple array of 20 icebergs of uniform dimensions equally spaced within the fjord. We find that the presence of these icebergs acts to (1) slow down the propagation of both external and internal seiches and (2) introduce band gaps where energy propagation (group velocity) vanishes. If energy is introduced into the fjord within the period range covered by a band gap, it will remain trapped as an evanescent oscillatory mode near its source, thus contributing to localized energy dissipation and ice/melange fragmentation.
Document Type: Research Article
Publication date: November 1, 2012
- The Annals of Glaciology is a peer-reviewed, thematic journal published 2 to 4 times a year by the International Glaciological Society (IGS). Publication frequency is determined and volume/issue numbers assigned by the IGS Council on a year-to-year basis and with a lead time of 3 to 4 years. The Annals of Glaciology is included in the ISI Science Citation Index from volume 50, number 50 onwards.
Themes can be on any aspect of the study of snow and ice. Individual members can make a suggestion for a theme for an Annals issue to the Secretary General, who will forward it to the IGS Publications Committee. The IGS Publication Committee will make a recommendation for an individual themed Annals issue, together with a potential Annals Chief Editor for that issue, to IGS Council. The IGS Council will make the decision whether to proceed, taking into account the spread of topics and the overall capacity for publication of pages in Annals.
- Editorial Board
- Information for Authors
- ingentaconnect is not responsible for the content or availability of external websites