A Numerical Study of Interannual Variability in the North Icelandic Irminger Current

Jian Zhao, Jiayan Yang, Stefanie Semper, Robert S. Pickart, Kjetil Våge, Hedinn Valdimarsson, Steingrímur Jónsson

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

The North Icelandic Irminger Current (NIIC) is an important component of the Atlantic Water (AW) inflow to the Nordic Seas. In this study, both observations and a high-resolution (1/12 ° ) numerical model are used to investigate the seasonal to interannual variability of the NIIC and its forcing mechanisms. The model-simulated velocity and hydrographic fields compare well with the available observations. The water mass over the entire north Icelandic shelf exhibits strong seasonal variations in both temperature and salinity, and such variations are closely tied to the AW seasonality in the NIIC. In addition to seasonal variability, there is considerable variation on interannual time scales, including a prominent event in 2003 when the AW volume transport increased by about 0.5 Sv. To identify and examine key forcing mechanisms for this event, we analyzed outputs from two additional numerical experiments: using only the seasonal climatology for buoyancy flux (the momentum case) and using only the seasonal climatology for wind stress (the buoyancy case). It is found that changes in the wind stress are predominantly responsible for the interannual variations in the AW volume transport, AW fraction in the NIIC water, and salinity. Temperature changes on the shelf, however, are equally attributable to the buoyancy flux and wind forcing. Correlational analyses indicate that the AW volume transport is most sensitive to the wind stress southwest of Iceland.

Original languageEnglish
Pages (from-to)8994-9009
Number of pages16
JournalJournal of Geophysical Research: Oceans
Volume123
Issue number12
DOIs
Publication statusPublished - 11 Oct 2018

Bibliographical note

Funding Information:
This work is supported by the U.S. National Science Foundation (NSF) under grants OCE-1634886 (J. Zhao and J. Yang) and OCE-1558742 (R. Pickart), and by the Bergen Research Foundation grant BFS2016REK01 (K. Våge and S. Semper). We thank Xiaobiao Xu at Florida State University for providing the initial model configuration. Comments from anonymous reviewers help to improve the manuscript. The altimeter products are produced and distributed by the Copernicus Marine and Environment Monitoring Service (CMEMS, http://www.marine. copernicus.eu). The hydrographic maps along the Hornbanki section are available at http://www.hafro.is/Sjora/.

Funding Information:
This work is supported by the U.S. National Science Foundation (NSF) under grants OCE-1634886 (J. Zhao and J. Yang) and OCE-1558742 (R. Pickart), and by the Bergen Research Foundation grant BFS2016REK01 (K. V?ge and S. Semper). We thank Xiaobiao Xu at Florida State University for providing the initial model configuration. Comments from anonymous reviewers help to improve the manuscript. The altimeter products are produced and distributed by the Copernicus Marine and Environment Monitoring Service (CMEMS, http://www.marine.copernicus.eu). The hydrographic maps along the Hornbanki section are available at http://www.hafro.is/Sjora/.

Publisher Copyright:
©2018. American Geophysical Union. All Rights Reserved.

Other keywords

  • interannual
  • Irminger Current
  • numerical modeling
  • wind

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