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The Role of the Irminger Current in the Irminger Sea Northward Transport Variability
Author(s) -
Fried Nora,
Jong M. Femke
Publication year - 2022
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2021jc018188
Subject(s) - oceanography , geology , mesoscale meteorology , boundary current , structural basin , climatology , ocean current , current (fluid) , paleontology
Abstract The Irminger Current (IC) on the western flank of the Reykjanes Ridge is an important contributor to the northward transport in the Atlantic Meridional Overturning Circulation. Here, we combine 28 years of Copernicus Marine Environment Monitoring Service (CMEMS) ocean reanalysis data with 6 years of mooring data to investigate variability in volume transport of the IC. We found a mean volume transport for the IC of 11.6 Sv between 1993 and 2020 revealing the dominance of the IC in the total Irminger Sea northward volume transport (20.3 Sv). We found a significant decrease (−3.7 Sv) in volume transport of the IC until 2011 followed by a steeper (but shorter, leading to +2.7 Sv) increase until 2020. These changes across the Irminger Sea section are dominated by the IC, which in turn are driven by changes in the density gradient across the Irminger Sea related to convection. On decadal and interannual time scales the IC volume transport is well correlated with the decrease in the sea surface height difference over the basin. In 2019, a temporary intensification of the western IC core led to an exceptionally strong volume transport of the IC with 20 Sv. This was caused by density changes within the IC boundaries due to the presence of mesoscale eddies. Thus, IC transport variability is a superposition of basin‐wide to local processes that influence the velocity field on different time scales.