HR: 11:05h
AN: OS32B-04    [Abstracts]
TI: The Heat Balance and the Breakdown of Density Stratification on the New England Inner Shelf During Fall 2003
AU: * Fewings, M R
AF: Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA 02543 United States
AU: Lentz, S J
AF: Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA 02543 United States
AU: Trowbridge, J H
AF: Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA 02543 United States
AU: Plueddemann, A J
AF: Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA 02543 United States
- AB: We describe the regional evolution of stratification in the Martha's Vineyard Coastal Observatory (MVCO) region from July~15 to October~25,~2003. The temperature, salinity, and density stratification are highly variable on time scales from hours to months. We concentrate on synoptic and longer timescales, including the ``fall breakdown'' of stratification in the inner shelf region. We contrast the behavior of the stratification at different moorings in a cross-shore line stretching from the 12- to the 27-m isobath: near the coast the stratification is less strong than at the offshore site. Decreases in stratification are episodic, are often followed by increases in stratification, and are often associated with downwelling-favorable winds. We discuss the relative importance of surface cooling, wind-driven mixing, alongshore advection, and wind-driven cross-shore advection (upwelling and downwelling circulation) to the maintenance, variability, and eventual breakdown of the stratification in this shallow inner continental shelf area. We use temperature, salinity, and velocity data from six moorings in an alongshore and cross-shore array, along with surface heat flux and wind stress data, to estimate the alongshore and cross-shore temperature, salinity, and density gradients and also the heat storage, surface heating, and advective terms in the heat budget for each of three of the cross-shore moorings. We look at the temporal behavior of different terms in the heat budget as an aid for interpreting changes in the stratification. The time-integrated heat budget is far from a one-dimensional balance in this inner shelf region: the heat content at the 12- to 27-m sites is relatively constant in time, rather than increasing in a direct response to the surface heat flux. On time scales of weeks to months, the primary balance is between the surface and cross-shelf heat fluxes. On time scales of a few days, however, the variations in heat content and cross-shelf heat flux are large compared to variations in the surface heat flux.
DE: 4219 Continental shelf processes
DE: 4279 Upwelling and convergences
DE: 4504 Air/sea interactions (0312)
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting