Variability in the North Atlantic Deep Western Boundary Current : upstream causes and downstream effects as observed at Line W
MetadataShow full item record
LocationDeep Western Boundary Current
KeywordOcean currents; Ocean temperature; Endeavor (Ship: 1976-) Cruise EN256; Endeavor (Ship: 1976-) Cruise EN257; 440; Knorr (Ship : 1970-) Cruise KN173-2; Oceanus (Ship : 1975-) Cruise OC269; Oceanus (Ship : 1975-) Cruise OC401; Oceanus (Ship : 1975-) Cruise OC411; Oceanus (Ship : 1975-) Cruise OC417; Oceanus (Ship : 1975-) Cruise OC421; Oceanus (Ship : 1975-) Cruise OC432; Oceanus (Ship : 1975-) Cruise OC436; Oceanus (Ship : 1975-) Cruise OC446
The variability in the DWBC, its connection to the forcing in the northern North Atlantic and interaction with the Gulf Stream were explored from a combination of remote sensing and in-situ measurements in the western North Atlantic. Using satellite altimetry and Sea Surface Temperature (SST) we found evidence of the relation between changes in the Gulf Stream path and the variability in the temperature and velocity fields in the Slope Water. This relation was such that southward shifts of the main axis of the Gulf Stream were preceded by cold temperature anomalies and intensification of the southwestward flow. The analysis of 5.5 years of moored CTD and horizontal velocity data in the DWBC at 69°W recorded during the period 2002-2008, showed that the variability along the DWBC is linked to changes in the dense water formation regions. The evolution of potential vorticity (PV) at the mooring site, characterized by a transition from deep to upper Labrador Sea Water (LSW), was similar to that observed in the Labrador Sea 6 to 9 years earlier, and imply spreading rates for the LSW that varied over time from 1.5 to 2.5cm/s. The time dependence of the spreading rates was in good agreement with changes in the strength of the DWBC at the mooring site. The evolution of the DWBC transport was explored in more detail from a 5-element moored array, also at 69°W. The results, for the period of 2004-2008, were consistent with the single mooring analysis. The variability measured from the array showed that upper, intermediate and deep water mass layers expand and contract at each other’s expense, leading to alternating positive and negative PV anomalies at the upper-LSW, deep-LSW and Overflow Water (OW). Larger DWBC transports were associated with enhanced presence of recently ventilated upper-LSW and OW, rather than deep-LSW. The relative contribution of the different water masses to the observed circulation was investigated by inverting individual PV anomalies isolated from the observations. We found that changes in the depth-integrated circulation were mostly driven by changes in the OW.
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2010
Suggested CitationThesis: Pena-Molino, Beatriz, "Variability in the North Atlantic Deep Western Boundary Current : upstream causes and downstream effects as observed at Line W", 2010-09, DOI:10.1575/1912/4080, https://hdl.handle.net/1912/4080
Showing items related by title, author, creator and subject.
Irish, James D.; Kerry, S.; Fucile, Paul D.; Beardsley, Robert C.; Lord, Jeffrey; Brink, Kenneth H. (Woods Hole Oceanographic Institution, 2005-12)As part of the U.S. GLOBEC Northwest Atlantic/Georges Bank program, moorings were deployed on Georges Bank as part of the broad-scale survey component to help measure the temporal variability of both physical and biological ...
Acoustic and oceanographic observations and configuration information for the WHOI moorings from the SW06 experiment Newhall, Arthur E.; Duda, Timothy F.; von der Heydt, Keith; Irish, James D.; Kemp, John N.; Lerner, Steven A.; Liberatore, Stephen P.; Lin, Ying-Tsong; Lynch, James F.; Maffei, Andrew R.; Morozov, Andrey K.; Shmelev, Alexey A.; Sellers, Cynthia J.; Witzell, Warren E. (Woods Hole Oceanographic Institution, 2007-05)This document describes data, sensors, and other useful information pertaining to the moorings that were deployed from the R/V Knorr from July 24th to August 4th, 2006 in support of the SW06 experiment. The SW06 experiment ...
Efficient representation of the hydrographic structure of the north Atlantic Ocean and aspects of the circulation from objective methods Fukumori, Ichiro (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1989-03)The general theme of this thesis is the study of systematic mathematical techniques for determining the ocean circulation from classical hydrographic data. Two aspects of this theme are analyzed. The first is finding an ...