Hydrographic structure of overflow water passing through the Denmark Strait

• Main Author: Mastropole, Dana M.
• Format: Thesis
• Language: English
• Published: Massachusetts Institute of Technology and Woods Hole Oceanographic Institution 2015
• Subjects: Greenland; Irminger Sea; Denmark Strait; Greenland-Scotland Ridge; Nordic Seas; North Atlantic Deep Water; North Atlantic
• Online Access: https://hdl.handle.net/1912/7654

Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2015 Denmark Strait Overflow Water (DSOW) constitutes the densest portion of North Atlantic Deep Water, which feeds the lower limb of the Atlantic Meridional Overturning Circulation (AMOC). As such, it is critical to understand how DSOW is transferred from the upstream basins in the Nordic Seas, across the Greenland-Scotland Ridge, and to the North Atlantic Ocean. The goal of this study is to characterize the hydrographic structure of the different DSOW constituents at the sill before the water descends into the Irminger Sea using temperature and salinity (T/S) data from 111 shipboard crossings in the vicinity of the sill, collected between 1990 and 2012. The individual realizations indicate that weakly stratified "boluses" of DSOW frequent the sill and contribute the densest water to the overflow. This study also characterizes the structure, size, and location of the boluses and relates them to the T/S modes found at the sill. Lastly, historical hydrographic data from the Nordic Seas are used to make inferences regarding the origin of the boluses. Financial support for this work was provided by the National Science Foundation grant OCE-0959381.