Internal Wave Frequency Spectrum in the Amundsen Basin of the Arctic Ocean Inferred from Ice Tethered CTD Instruments

2018 ◽  
pp. 581-590
Author(s):  
Sergey V. Pisarev
Keyword(s):  
Internal Wave ◽  
Arctic Ocean ◽  
Frequency Spectrum ◽  
Wave Frequency ◽  
The Arctic ◽  
The Arctic Ocean

Changes in Internal Wave‐Driven Mixing Across the Arctic Ocean: Finescale Estimates From an 18‐Year Pan‐Arctic Record

2021 ◽  
Vol 48 (8) ◽  
Author(s):  
H. V. Dosser ◽  
M. Chanona ◽  
S. Waterman ◽  
N. C. Shibley ◽  
M.‐L. Timmermans
Keyword(s):  
Internal Wave ◽  
Arctic Ocean ◽  
The Arctic ◽  
The Arctic Ocean

scholarly journals Dynamics in the Deep Canada Basin, Arctic Ocean, Inferred by Thermistor Chain Time Series

2007 ◽  
Vol 37 (4) ◽  
pp. 1066-1076 ◽  
Author(s):  
M-L. Timmermans ◽  
H. Melling ◽  
L. Rainville
Keyword(s):  
Time Series ◽  
High Resolution ◽  
Internal Wave ◽  
Arctic Ocean ◽  
Temperature Fluctuations ◽  
Canada Basin ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Vertical Displacements ◽  
Wave Energy Flux

Abstract A 50-day time series of high-resolution temperature in the deepest layers of the Canada Basin in the Arctic Ocean indicates that the deep Canada Basin is a dynamically active environment, not the quiet, stable basin often assumed. Vertical motions at the near-inertial (tidal) frequency have amplitudes of 10– 20 m. These vertical displacements are surprisingly large considering the downward near-inertial internal wave energy flux typically observed in the Canada Basin. In addition to motion in the internal-wave frequency band, the measurements indicate distinctive subinertial temperature fluctuations, possibly due to intrusions of new water masses.

Nonlinear internal wave generation over the Yermak Plateau 

2021 ◽  
Author(s):  
Gabin Urbancic ◽  
Kevin Lamb ◽  
Ilker Fer ◽  
Laurie Padman
Keyword(s):  
Internal Wave ◽  
Arctic Ocean ◽  
Internal Waves ◽  
Wave Generation ◽  
The Arctic ◽  
Nonlinear Internal Wave ◽  
Nonlinear Internal Waves ◽  
The Arctic Ocean ◽  
Yermak Plateau ◽  
Internal Wave Generation

<p>North of the critical latitude (78.4), internal waves of the M<sub>2</sub> tidal frequency can no longer freely propagate, and the energy conversion from the barotropic to the internal tides vanishes. Near the continental slopes around the Arctic Ocean, internal wave energy is enhanced and comparable to values at mid-latitudes (Rippeth et al. 2015, Levine et al. 1985). Observations on the northern flank of the Yermak Plateau (YP) has characterized the region as one of enhanced internal wave activity and nonlinear internal waves have been observed (Czipott et al. 1991, Padman and Dillon 1991).</p><p>The YP is a bathymetry feature stretching out into the Fram Strait north-west of Svalbard. The YP plays a prominent role in the Arctic’s heat balance due to its interaction with the West-Spitsbergen current which is a main contributor to the heat transport into the Arctic Ocean. Nonlinear waves generated over the YP are a significant energy source for mixing and can therefore modulate and force exchange processes.</p><p>To study the nonlinear internal wave generation mechanisms over the YP, we used a high resolution, nonlinear, non-hydrostatic model. We found that nonlinear internal waves are forced not by the M<sub>2</sub> but the K<sub>1</sub> tide which has been observed to have significant variability over the YP (Padman et al. 1992). Barotropic, diurnal shelf waves generated on the eastern side of the YP propagates counter-clockwise, amplifying the cross-slope currents. This amplification is the necessary condition for nonlinear internal wave generation over the YP.</p>

Quantifying mixing from standard observations: revisiting finescale parameterization in the Arctic Ocean

2021 ◽  
Author(s):  
Till Baumann ◽  
Ilker Fer ◽  
Kirstin Schulz ◽  
Volker Mohrholz ◽  
Janin Schaffer ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Internal Wave ◽  
Arctic Ocean ◽  
Wave Field ◽  
Turbulent Mixing ◽  
Dissipation Rate ◽  
The Arctic ◽  
Depth Range ◽  
The Arctic Ocean ◽  
Internal Wave Field

<p>Ocean mixing governs the vertical exchange of matter, heat and salt in the water column. In the Arctic Ocean, the vertical transport of heat due to turbulent mixing is ultimately coupled to the sea-ice cover, with immediate and far-reaching impacts on the climate and ecosystem. A detailed understanding and quantification of turbulent mixing is crucial to assess and predict the state of the changing Arctic Ocean. However, direct observations of turbulent mixing are complicated, expensive and sparse.</p><p>Finescale parameterization of turbulent energy dissipation allows for the quantification of mixing based on standard hydrographic observations such as velocity and density profiles. This method is based on the assumption that energy dissipation is achieved exclusively by cascading energy from large, observable scales to small scales by wave-to-wave interactions in the internal wave field, which in turn can be related to vertical diffusivity and hence turbulent fluxes. While the finescale parameterization is proved to be reliable at mid-latitudes, the Arctic Ocean internal wave field is distinct from the canonical mid-latitude spectrum and the applicability of the parameterization is not certain. Furthermore, in the historically quiescent Arctic, the application of finescale parameterization suffers from a generally low signal to noise ratio and processes violating the assumptions in the parameterization, such as double diffusion.  During the year-long MOSAiC expedition, both standard observations as well as specialized microstructure measurements were carried out continuously. We analyse dissipation rate and stratification measurements (from an MSS90L profiler) and 8-m vertical resolution current measurements (from a 75 kHz RDI acoustic Doppler current profiler) in the depth range from 70 -198 m, in the absence of thermohaline staircases or double-diffusive intrusions. Although the range of dissipation measurements is limited and spans 1e<sup>-11</sup> W kg<sup>-1</sup> to 8.8e<sup>-7</sup> W kg<sup>-1</sup>, direct comparisons between in-situ observations of dissipation rate and finescale parameterization provide a detailed insight into the capabilities and limitations of this method in various meteorological, oceanographic and geographic conditions. The aim is to provide guidance in how far standard oceanographic observations may be utilized to quantify mixing in past, current and future states of the Arctic Ocean.</p>

Ice Flexure Forced by Internal Wave Packets in the Arctic Ocean

Science ◽  
1991 ◽  
Vol 254 (5033) ◽  
pp. 832-835 ◽  
Author(s):  
P. V. CZIPOTT ◽  
M. D. LEVINE ◽  
C. A. PAULSON ◽  
D. MENEMENLIS ◽  
D. M. FARMER ◽  
...  
Keyword(s):  
Internal Wave ◽  
Arctic Ocean ◽  
Wave Packets ◽  
The Arctic ◽  
The Arctic Ocean

Internal Waves and Mixing in the Marginal Ice Zone near the Yermak Plateau*

2010 ◽  
Vol 40 (7) ◽  
pp. 1613-1630 ◽  
Author(s):  
Ilker Fer ◽  
Ragnheid Skogseth ◽  
Florian Geyer
Keyword(s):  
Internal Wave ◽  
Arctic Ocean ◽  
Internal Waves ◽  
Noise Level ◽  
Atlantic Water ◽  
The Arctic ◽  
Cold Side ◽  
Marginal Ice Zone ◽  
The Arctic Ocean ◽  
Yermak Plateau

Abstract Observations were made of oceanic currents, hydrography, and microstructure in the southern Yermak Plateau in summer 2007. The location is in the marginal ice zone at the Arctic Front northwest of Svalbard, where the West Spitsbergen Current (WSC) carries the warm Atlantic Water into the Arctic Ocean. Time series of approximately 1-day duration from five stations (upper 520 m) and of an 8-day duration from a mooring are analyzed to describe the characteristics of internal waves and turbulent mixing. The spectral composition of the internal-wave field over the southern Yermak Plateau is 0.1–0.3 times the midlatitude levels and compares with the most energetic levels in the central Arctic. Dissipation rate and eddy diffusivity below the pycnocline increase from the noise level on the cold side of the front by one order of magnitude on the warm side, where 100-m-thick layers with average diffusivities of 5 × 10−5 m2 s−1 lead to heat loss from the Atlantic Water of 2–4 W m−2. Dissipation in the upper 150 m is well above the noise level at all stations, but strong stratification at the cold side of the front prohibits mixing across the pycnocline. Close to the shelf, at the core of the Svalbard branch of the WSC, diffusivity increases by another factor of 3–6. Here, near-bottom mixing removes 15 W m−2 of heat from the Atlantic layer. Internal-wave activity and mixing show variability related to topography and hydrography; thus, the path of the WSC will affect the cooling and freshening of the Atlantic inflow. When generalized to the Arctic Ocean, diapycnal mixing away from abyssal plains can be significant for the heat budget. Around the Yermak Plateau, it is of sufficient magnitude to influence heat anomaly pulses entering the Arctic Ocean; however, diapycnal mixing alone is unlikely to be significant for regional cooling of the WSC.

The impact of multiple layering on internal wave transmission

2016 ◽  
Vol 789 ◽  
pp. 617-629 ◽  
Author(s):  
S. J. Ghaemsaidi ◽  
H. V. Dosser ◽  
L. Rainville ◽  
T. Peacock
Keyword(s):  
Experimental Study ◽  
Wave Propagation ◽  
Internal Wave ◽  
Arctic Ocean ◽  
The Arctic ◽  
Simplified Model ◽  
The Arctic Ocean ◽  
The Impact ◽  
Double Diffusive

Given the ubiquity of layering in environmental stratifications, an interesting example being double-diffusive staircase structures in the Arctic Ocean, we present the results of a joint theoretical and laboratory experimental study investigating the impact of multiple layering on internal wave propagation. We first present results for a simplified model that demonstrates the non-trivial impact of multiple layering. Thereafter, utilizing a weakly viscous linear model that can handle arbitrary vertical stratifications, we perform a comparison of theory with experiments. We conclude by applying this model to a case study of a staircase stratification profile obtained from the Arctic Ocean, finding a rich landscape of transmission behaviour.

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