Wind-forced dynamics in Bonne Bay, Newfoundland.

摘要

Ten Acoustic Doppler Current Profilers were deployed between September 2002 and September 2004 on the sill of the East Arm in Bonne Bay, a glacial fjord in Gros Morne National Park on the west coast of Newfoundland. The moorings were deployed to measure the velocity of water flowing over the sill, in order to better understand the exchange dynamics of the system. In addition to the current meter data, several cruises were conducted in June 2004 to collect hydrographic data in the Bay, specifically temperature, salinity and density profiles. Meteorological data from the area are also presented. Tidal flow over the sill is dominated by the M2 tide, with a vertical asymmetry between ebb and flood tides due to the superposition of the estuarine flow. Internal tides were detected during times of the year when the stratification supports internal motions. Similarly, tidal currents were seen to give rise to higher frequency flow (periods less than 5 hours) attributed to high frequency internal waves. Subtidal flow over the sill is two layer, and is primarily forced by the local wind stress. The development of a simple two layer numerical model supports this analysis, and with it some of the effects of spatially varying wind stress were examined. Topographic steering of the wind in the region was determined to be significant in accounting for discrepancies between data and model results.