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GLOBEC long-term moored effort: Five years of moored observations on the southern flank of Georges Bank

James D. Irish, Ph.D.
Woods Hole Oceanographic Institute

Wednesday, January 19, 2000
3:00 p.m.—Pacific Forum

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The U.S. GLOBEC program is trying to understand the underlying physical and biological processes that control the abundance of key populations of marine animals in space and time. The Northwest Atlantic/Georges Bank Program is focused on the pelagic life stages of cod and haddock and their major prey, Calanus finmarchicus and Pseudocalanus. The long-term moored effort is collecting time series observations (in conjunction with shipboard, more detailed process studies, satellite and drifters). We are studying the temporal variability of the atmospheric forcing and its relationship to the resulting water property, stratification and circulation variability on Georges Bank—eventually evaluating its effect on the biology.

A mooring was maintained for five years on the southern flank of Georges Bank in 76 meters of water. Preliminary results show the large variability on tidal, annual, and inter-annual scales. Strong intrusive signals (warm core rings and Scotian shelf water) were partially averaged across (subjectively) to show the long-term trends of the water properties plotted below. Temperatures show annual heating in summer and cooling in winter. In 1995 and 1999 warm core ring effects were persistent enough that they showed up as apparent warmer years. The salinity varies around 33 with a 6-month cycle until the end of 1995. During the first half of 1996 the salinity decreases 1 to 32. From mid-1996 to mid-1997 the salinity increases to 32.5; then from mid 1997 to 1998, it decreases again to below 32. From mid-1998 until the end of the deployment, the salinity again shows a rise to above 32.5.

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 Last updated: December 19, 2000