HR: 0830h
AN: OS21C-1136    [PDF]
TI: What is the impact of the observed freshening of the Labrador Sea on its convective cycle?
AU: * Straneo, F
EM: fstraneo@whoi.edu
AF: Woods Hole Oceanographic Instit., Dept. of Physical Ocean., MS #21, Woods Hole, MA 02543 United States
AB: As a region of intermediate water formation, the Labrador Sea plays an important role in the North Atlantic's meridional overturning circulation and poleward heat transport. Given the recently reported freshening of the high-latitude North Atlantic and of the Labrador Sea, in particular, this study investigates the impact of such changes on deep convection in the Labrador Sea. A `typical' convective cycle for the upper 1500m of the central Labrador Sea is constructed for two time periods three decades apart: from 1964 to 1974 (using hydrographic data collected at Ocean Weather Station Bravo) and from 1996 to 2000 (using P-ALACE float temperature and salinity profiles). The two cycles are compared using a dynamical framework which separates the seasonal cycle into a convection and a restratification phase and vertically partitions the water column into three layers: surface, intermediate and convective. The mechanisms of convection and restratification in the two periods are found to be similar, suggesting that these are strongly controlled by isopycnal dynamics and that the freshening has been compensated by a cooling. The comparison, however, also shows that changes in the heat and freshwater transport through the convective region may have occurred between the two periods.
DE: 4215 Climate and interannual variability (3309)
DE: 4243 Marginal and semienclosed seas
DE: 4283 Water masses
DE: 4532 General circulation
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting