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Modelling the shelf circulation off eastern Tasmania

Citation

Oliver, ECJ and Herzfeld, M and Holbrook, NJ, Modelling the shelf circulation off eastern Tasmania, Continental Shelf Research, 130 pp. 14-33. ISSN 0278-4343 (2016) [Refereed Article]

Copyright Statement

2016 Elsevier Ltd.

DOI: doi:10.1016/j.csr.2016.10.005

Abstract

The marine waters across Tasmanian's eastern continental shelf are biologically productive and home to economically important fisheries and aquaculture industries. However, the marine climate there is poorly understood. We use a high-resolution (∼2 km in the horizontal), three-dimensional ocean model for eastern Tasmania (ETAS) to examine the simulated mean state and seasonal cycle of temperature, salinity and three-dimensional flow field, and the evaluation of daily model outputs against in situ and remote observations for the 1993-2014 period. We also use the model to examine the roles of river input and tidal forcing. The model is evaluated against remotely-sensed sea surface temperature and in-situ observations of sea level and subsurface temperature, salinity, and currents. The mean state demonstrates the influence of two well-known boundary currents (the East Australian Current, EAC, and the Zeehan Current, ZC) as well as the effects of local freshwater input from river runoff. The EAC is dominant in summer and the ZC in winter; the influence of the EAC also increases northwards and in the offshore direction. In addition, the model indicates the presence of a semi-permanent subsurface (50-100 m depth) northward flow trapped near the coast. Cool freshwater runoff from the Derwent and Huon Rivers directly impacts the temperature and salinity in their estuaries but has little influence further across the shelf. Tidal forcing impacts the mean state through tide-river interactions which flush Frederick Henry Bay and Norfolk Bay with freshwater. Tidal forcing also impacts the variability of temperature all along the coastline, most likely due to changes in the turbulent mixing near to the coast. The ETAS model output data are available as a high-resolution representation of the mean state, seasonal variations, and interannual variability of Tasmania's eastern continental shelf marine climate.

Item Details

Item Type:Refereed Article
Keywords:ocean circulation, continental shelf circulation, seasonal variability, Tasmania, boundary current, seasonal cycle
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical Oceanography
Objective Division:Environment
Objective Group:Climate and Climate Change
Objective Field:Climate Variability (excl. Social Impacts)
Author:Oliver, ECJ (Dr Eric Oliver)
Author:Holbrook, NJ (Associate Professor Neil Holbrook)
ID Code:112292
Year Published:2016
Deposited By:Centre for Oceans and Cryosphere
Deposited On:2016-11-02
Last Modified:2017-11-09
Downloads:0

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