Structure and forcing of observed exchanges across the Greenland–Scotland Ridge
Spall, Michael A.
MetadataShow full item record
KeywordOcean circulation; Thermocline circulation; Atmosphere-ocean interaction; North Atlantic Oscillation; Statistical techniques; Time series
The Atlantic meridional overturning circulation and associated poleward heat transport are balanced by northern heat loss to the atmosphere and corresponding water-mass transformation. The circulation of northward-flowing Atlantic Water at the surface and returning overflow water at depth is particularly manifested—and observed—at the Greenland–Scotland Ridge where the water masses are guided through narrow straits. There is, however, a rich variability in the exchange of water masses across the ridge on all time scales. Focusing on seasonal and interannual time scales, and particularly the gateways of the Denmark Strait and between the Faroe Islands and Shetland, we specifically assess to what extent the exchanges of water masses across the Greenland–Scotland Ridge relate to wind forcing. On seasonal time scales, the variance explained of the observed exchanges can largely be related to large-scale wind patterns, and a conceptual model shows how this wind forcing can manifest via a barotropic, cyclonic circulation. On interannual time scales, the wind stress impact is less direct as baroclinic mechanisms gain importance and observations indicate a shift in the overflows from being more barotropically to more baroclinically forced during the observation period. Overall, the observed Greenland–Scotland Ridge exchanges reflect a horizontal (cyclonic) circulation on seasonal time scales, while the interannual variability more represents an overturning circulation.
Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 31 (2018): 9881-9901, doi:10.1175/JCLI-D-17-0889.1.
Suggested CitationJournal of Climate 31 (2018): 9881-9901
Showing items related by title, author, creator and subject.
Schmitz, William J. (Woods Hole Oceanographic Institution, 1996-06)This is the first volume of a "final report" that summarizes, often in a speculative vein, what I have learned over the past 35 years or so about large-scale, low-frequency ocean currents, primarily with support from the ...
Macdonald, Alison M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1995-08)Data from fifteen globally distributed, modern, high resolution, hydrographic oceanic transects are combined in an inverse calculation using large scale box models. The models provide estimates of the global meridional ...
Near-surface transport pathways in the north Atlantic Ocean : looking for throughput from the subtropical to the subpolar gyre Rypina, Irina I.; Pratt, Lawrence J.; Lozier, M. Susan (American Meteorological Society, 2011-05)Motivated by discrepancies between Eulerian transport estimates and the behavior of Lagrangian surface drifters, near-surface transport pathways and processes in the North Atlantic are studied using a combination of data, ...