Publication Date:
2022-05-25
Description:
Author Posting. © The Authors, 2018. This article is posted here by permission of Sears Foundation for Marine Research for personal use, not for redistribution. The definitive version was published in Journal of Marine Research 76 (2018): 47-62, doi:10.1357/002224018824845910.
Description:
We describe the high-frequency variability in the North Icelandic Jet (NIJ) on the Iceland Slope
using data from the densely instrumented Kögur mooring array deployed upstream of the Denmark
Strait sill from September 2011 to July 2012. Significant sub-8-day variability is ubiquitous in all
moorings from the Iceland slope with a dominant period of 3.6 days. We attribute this variability to
topographic Rossby waves on the Iceland slope with a wavelength of 62 ± 3 km and a phase velocity
of 17.3 ± 0.8 km/day−1 directed downslope (−9◦ relative to true-north). We test the theoretical
dispersion relation for these waves against our observations and find good agreement between the
predicted and measured direction of phase propagation.We additionally calculate a theoretical group
velocity of 36 km day−1 directed almost directly up-slope (106◦ relative to true-north) that agrees
well with the propagation speed and direction of observed energy pulses. We use an inverse wave
tracing model to show that this wave energy is generated locally, offshore of the array, and does not
emanate from the upstream or downstream directions along the Iceland slope. It is hypothesized that
either the meandering Separated East Greenland Current located seaward of the NIJ or intermittent
aspiration of dense water into the Denmark Strait Overflow are the drivers of the topographic waves.
Description:
This work was supported by National Science Foundation grants OCE-1433958 (BH), OCE-0959381 (BH and RP)
and OCE-1558742 (RP).
Keywords:
Topographic waves
;
Denmark Strait
;
AMOC
;
North Icelandic Jet
Repository Name:
Woods Hole Open Access Server
Type:
Article
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