Abstract


MODELLING THE CIRCULATION OF A SEMI-ENCLOSED ISOLATED CORAL REEF ATOLL

The hydrodynamics of coral reefs directly influence ecosystem diversity, productivity and community structure. Predicting the processes that drive reef circulation will facilitate understanding reef resilience when challenged by future climate change. Most studies on coral atolls have focused on shallow reef tops forced by surface waves, located primarily within microtidal regions. This study focuses on Scott Reef, an isolated reef atoll system that rises steeply from depths of 2500 m, ~300 km off northwestern Australia. The dynamics of North Scott, a shallow (~20m deep), semi-enclosed lagoon (exchange only through two narrow reef channels), with a spring tidal range of > 3 m, will be presented. A multidisciplinary research cruise took place during April 2015 to Scott Reef. To quantify the hydrodynamics of North Scott Lagoon, an array of moored instruments were deployed, including wave and tide gauges, and current meters/profilers. Field measurements indicate that the shallow reef crest acts to restrict exchange between the open ocean and the lagoon, resulting in a highly asymmetric tidal flows. A numerical model (DFLOW-FM) was developed using flexible mesh gridding to account for the complex bathymetry of the reef and lagoon, and was able to replicate the hydrodynamics. Water quality variables will be incorporated into the model, to not only provide insight into the physical forcing associated with the circulation and flushing of the lagoon, but also give an indication of the system's responses to projected future environmental disturbances.

Authors

Green, R., University of Western Australia, Australia, rebecca.green@research.uwa.edu.au

Lowe, R., University of Western Australia, Australia, ryan.lowe@uwa.edu.au

Roelvink, D., UNESCO-IHE, Australia, D.Roelvink@unesco-ihe.org

Reyns, J., UNESCO-IHE , Australia, J.Reyns@unesco-ihe.org

Details

Oral presentation

Session #:50
Date: 06/23/2016
Time: 14:30
Location: 312

Presentation is given by student: Yes