Wind-forced Motion on the Northern Great Barrier Reef

Abstract

Abstract Observations of current, bottom pressure, and wind from the shelf of the Northern Great Barrier Reefare interpreted using a two-layer, frictional, step-shelf model forced by propagating wind stress. Distinguishing features of the region are the many reefs on the shallow shelf, the well-mixed nature of the shelf waters, and the steep continental slope. The instrument army was deployed from April to October 1982 and comprised 14 current meters, nine pressure gauges, and two weather stations. Low-pass [<0,6 cycles per day (cpd)] filtered velocity and pressure data are analyzed separately using a time domain empirical orthogonal function (EOF) analysis. The first EOFs of both velocity and pressure data are found to account for most of the observed variance on the shelf. Time series of these two EOFs are both highly coherent, with the local longshore wind stress at “weatherband” frequencies(<0.3cpd);however, the frequency transfer functions of the wind to the current and of the wind to the pressure ar...