On the Currents and Transports Connected with the Atlantic Meridional Overtuning Circulation in the Subpolar North Atlantic

• Main Authors: Xu, X, Hurlburt, H E, Schmitz, Jr , W J, Zantopp, R, Fischer, J, Hogan, P J
• Other Authors: NAVAL RESEARCH LAB STENNIS DETACHMENT STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
• Format: Text
• Language: English
• Published: 2013
• Subjects: Physical and Dynamic Oceanography; *NORTH ATLANTIC OCEAN; *OCEAN CURRENTS; *OCEAN MODELS; *TIME SERIES ANALYSIS; *TRANSPORT; *VARIATIONS; BATHYMETRY; COMPUTERIZED SIMULATION; EDDIES(FLUID MECHANICS); HYDROGRAPHIC SURVEYING; LONG RANGE(TIME); REPRINTS; SHORT RANGE(TIME); TEMPERATURE; *ATLANTIC MERIDIONAL OVERTURNING CIRCULATION; *SUBPOLAR NORTH ATLANTIC OCEAN; *TRANSPORT VARIABILITY; *HYCOM(HYBRID COORDINATE OCEAN MODEL); OVERFLOW WATER TRANSPORTS; SEA SURFACE HEIGHT; BOUNDARY CURRENT TRANSPORTS; WESTERN BOUNDARY CURRENT; DECADAL TRANSPORT VARIATIONS; TRANS-BASIN TRANSPORTS; MERIDIONAL TRANSPORTS; PE0601153N; WU735732115; Labrador Sea; North Atlantic; North Atlantic oscillation
• Online Access: http://www.dtic.mil/docs/citations/ADA582691; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA582691

Results from an interannually forced, 0.08 degree eddy-resolving simulation based on the Hybrid Coordinate Ocean Model, in conjunction with a small but well-determined transport database, are used to investigate the currents and transports associated with the Atlantic meridional overturning circulation (AMOC) in the subpolar North Atlantic (SPNA). The model results yield a consistent warming in the western SPNA since the early 1990s, along with mean transports similar to those observed for the trans-basin AMOC across the World Ocean Circulation Experiment hydrographic section AR19 (16.4 Sv) and boundary currents at the exit of the Labrador Sea near 53 degrees N (39.0 Sv) and east of the Grand Banks near 43 degrees N (15.9 Sv). Over a 34-year integration, the model-determined AMOC across the AR19 section and the western boundary current near 53 degrees N both exhibit no systematic trend but some long-term (interannual and longer) variabilities, including a decadal transport variation of 3-4 Sv from relatively high in the 1990s to low in the 2000s. The decadal variability of the model boundary current transport near 53 degrees N lags the observed winter time North Atlantic Oscillation index by about 2 years and leads the model AMOC across the AR19 section by about 1 year. The model results also show that the long-term variabilities are low compared to those on shorter time scales. Thus, rapid sampling of the current over long time intervals is required to filter out high-frequency variabilities to determine the lower frequency variabilities of interest. Published in the Journal of Geophysical Research: Oceans, v118 p502-516, 2013. The original document contains color images.