Ventilation times scales for a subtropical bay from 3-D modelling

Grawe, U. and Ribbe, J. and Wolff, J.-O. and Staneva, J. (2007) Ventilation times scales for a subtropical bay from 3-D modelling. In: 4th European Geosciences Union General Assembly 2007, 15–20 April 2007, Vienna, Austria.


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[Abstract]: We applied a multi-purpose three-dimensional ocean general circulation model to
compute water renewal time scales for a large coastal embayment situated off the
central eastern coast of Australia (Hervey Bay) that shows features of an inverse estuary.
Water renewal or ventilation time scales are not directly observable but can easily
be diagnosed from numerical simulations. Improved knowledge of these time scales
can assists in evaluating the water quality of coastal environments and can be utilised
in sustainable marine resource management.
The numerical studies are performed with the COupled Hydrodynamical Ecological
model for REgioNal Shelf seas (COHERENS). The model, adopted for Hervey Bay,
provided insight into ventilation pathways, and renewal time scales were found to exhibit
a strong spatial variability. More than 80 % of the coastal embayment was fully
ventilated after about 70-100 days, with the eastern and western shallow coastal regions
ventilated more rapidly than the central, deeper part of the bay.
The concept of a single ’typical’ ventilation timescale characterising this particular
coastal embayment is inadequate and the consideration of spatial variability is clearly
important, hence in a second set of simulations local monitoring boxes and Lagrangian
tracers have been used to focus on this spatial variability. Simple parameters are derived
to estimate local sedimentation, transport processes or places of high/low biological

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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Paper)
Refereed: Yes
Item Status: Live Archive
Additional Information: Authors retain copyright. Conference publication consists of only the abstracts of papers presented at the conference (free-access online publication). Abstract only posted here.
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 11 Oct 2007 00:57
Last Modified: 02 Jul 2013 22:42
Uncontrolled Keywords: water renewal, ventilation time scales, water quality
Fields of Research : 04 Earth Sciences > 0405 Oceanography > 040503 Physical Oceanography

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