Long-term moored observations on geores bank as part of the U.S. GLOBEC northwest Atlantic/Georges bank program

摘要

Moored measurements have been made on Georges Bank from fall 1994 to fall 1999 as part of the US GLOBEC Northwest Atlantic/Georges Bank Program. The southern flank mooring was located in 76 m of water between the shelf/slope front, which separates the North Atlantic from Georges Bank, and the tidally well-mixed region over the crest of the bank. The mooring carried a full suite of meteorological sensors and water temperature and conductivity (salinity) sensors at many depths, an Acoustic DopplerCurrent Profiler to measure currents over much of the water column, and bio-optical sensors to measure biological variables.The temperature and salinity data show great variability on time scales from tidal to inter-annual. Warm-core rings occasionally "bumped" into Georges Bank, and their effects (warm, salty, biologically inactive water) often extend onto the bank. Pulses of Scotian Shelf water (cold and fresh) were observed to move westward along the southern flank. Salinity shows a steady, long-term decrease by greater than one PSU over the first four years of observations with only a small indication of a reversal in 1999. A five-year moored record is a significant achievement, but with the large variability observed in the coastal ocean, longer records are needed to help relate long-term oceanic changes to climate changes.