scholarly journals Spurious rollover of wave attenuation rates in sea ice caused by noise in field measurements

2021 ◽  
Author(s):  
Jim Thomson ◽  
Lucia Hošeková ◽  
Michael H. Meylan ◽  
Alison L Kohout ◽  
Nirnimesh Kumar
Keyword(s):  
Sea Ice ◽  
Wave Attenuation ◽  
Field Measurements

scholarly journals Spurious rollover of wave attenuation rates in sea ice caused by noise in field measurements

2021 ◽  
Author(s):  
Jim Thomson ◽  
Lucia Hosekova ◽  
Michael Howard Meylan ◽  
Alison Laura kohout ◽  
Nirnimesh Kumar
Keyword(s):  
Sea Ice ◽  
Wave Attenuation ◽  
Field Measurements

scholarly journals Spurious rollover of wave attenuation rates in sea ice caused by noise in field measurements

2020 ◽  
Author(s):  
Jim Thomson ◽  
Lucia Hosekova ◽  
Michael Howard Meylan ◽  
Alison Laura kohout ◽  
Nirnimesh Kumar
Keyword(s):  
Sea Ice ◽  
Wave Attenuation ◽  
Field Measurements

Surface-based and Fully Polarimetric L-band Frequency Scatterometer System for Field Measurements of Sea Ice

2021 ◽  
Author(s):  
Randall Kenneth Scharien ◽  
Torsten Geldsetzer ◽  
Jim Mead ◽  
Vishnu Nandan ◽  
Mallik Mahmud ◽  
...  
Keyword(s):  
Sea Ice ◽  
Field Measurements ◽  
Band Frequency ◽  
L Band

scholarly journals Implications of sea-ice biogeochemistry for oceanic production and emissions of dimethyl sulfide in the Arctic

2017 ◽  
Vol 14 (12) ◽  
pp. 3129-3155 ◽  
Author(s):  
Hakase Hayashida ◽  
Nadja Steiner ◽  
Adam Monahan ◽  
Virginie Galindo ◽  
Martine Lizotte ◽  
...  
Keyword(s):  
Sea Ice ◽  
Water Column ◽  
Dimethyl Sulfide ◽  
Phytoplankton Bloom ◽  
Model Simulation ◽  
Field Measurements ◽  
Sulfur Cycle ◽  
The Arctic ◽  
Model Parameters ◽  
Ocean Ecosystem

Abstract. Sea ice represents an additional oceanic source of the climatically active gas dimethyl sulfide (DMS) for the Arctic atmosphere. To what extent this source contributes to the dynamics of summertime Arctic clouds is, however, not known due to scarcity of field measurements. In this study, we developed a coupled sea ice–ocean ecosystem–sulfur cycle model to investigate the potential impact of bottom-ice DMS and its precursor dimethylsulfoniopropionate (DMSP) on the oceanic production and emissions of DMS in the Arctic. The results of the 1-D model simulation were compared with field data collected during May and June of 2010 in Resolute Passage. Our results reproduced the accumulation of DMS and DMSP in the bottom ice during the development of an ice algal bloom. The release of these sulfur species took place predominantly during the earlier phase of the melt period, resulting in an increase of DMS and DMSP in the underlying water column prior to the onset of an under-ice phytoplankton bloom. Production and removal rates of processes considered in the model are analyzed to identify the processes dominating the budgets of DMS and DMSP both in the bottom ice and the underlying water column. When openings in the ice were taken into account, the simulated sea–air DMS flux during the melt period was dominated by episodic spikes of up to 8.1 µmol m−2 d−1. Further model simulations were conducted to assess the effects of the incorporation of sea-ice biogeochemistry on DMS production and emissions, as well as the sensitivity of our results to changes of uncertain model parameters of the sea-ice sulfur cycle. The results highlight the importance of taking into account both the sea-ice sulfur cycle and ecosystem in the flux estimates of oceanic DMS near the ice margins and identify key uncertainties in processes and rates that should be better constrained by new observations.

scholarly journals Wave-induced stress and breaking of sea ice in a coupled hydrodynamic–discrete-element wave–ice model

2017 ◽  
Author(s):  
Agnieszka Herman
Keyword(s):  
Sea Ice ◽  
Wave Attenuation ◽  
Wave Model ◽  
Discrete Element ◽  
Two Dimensions ◽  
Particle Model ◽  
Time Step ◽  
Bonded Particle Model ◽  
Induced Stress ◽  
Wave Induced

Abstract. In this paper, a coupled sea ice–wave model is developed and used to analyze the variability of wave-induced stress and breaking in sea ice. The sea ice module is a discrete-element bonded-particle model, in which ice is represented as cuboid "grains" floating on the water surface that can be connected to their neighbors by elastic "joints". The joints may break if instantaneous stresses acting on them exceed their strength. The wave part is based on an open-source version of the Non-Hydrostatic WAVE model (NHWAVE). The two parts are coupled with proper boundary conditions for pressure and velocity, exchanged at every time step. In the present version, the model operates in two dimensions (one vertical and one horizontal) and is suitable for simulating compact ice in which heave and pitch motion dominates over surge. In a series of simulations with varying sea ice properties and incoming wavelength it is shown that wave-induced stress reaches maximum values at a certain distance from the ice edge. The value of maximum stress depends on both ice properties and characteristics of incoming waves, but, crucially for ice breaking, the location at which the maximum occurs does not change with the incoming wavelength. Consequently, both regular and random (Jonswap spectrum) waves break the ice into floes with almost identical sizes. The width of the zone of broken ice depends on ice strength and wave attenuation rates in the ice.

scholarly journals Wave Attenuation and Gas Exchange Velocity in Marginal Sea Ice Zone

2018 ◽  
Vol 123 (3) ◽  
pp. 2293-2304 ◽  
Author(s):  
A. Bigdeli ◽  
T. Hara ◽  
B. Loose ◽  
A. T. Nguyen
Keyword(s):  
Gas Exchange ◽  
Sea Ice ◽  
Wave Attenuation ◽  
Marginal Sea

Coupled processes in an ocean-sea ice-wave configuration

2021 ◽  
Author(s):  
Stefanie Rynders ◽  
Yevgeny Aksenov ◽  
Andrew Coward
Keyword(s):  
Sea Ice ◽  
Surface Waves ◽  
Wave Attenuation ◽  
Computational Cost ◽  
Breaking Waves ◽  
Coupled Processes ◽  
Computational Power ◽  
Marine Systems ◽  
Ocean Surface Waves ◽  
The Impact

<p>Marginal ice zones are areas with many interactions between ocean, surface waves, sea ice and atmosphere. Increasing computational power makes it possible to perform increasingly complex simulations of marine systems, with more components of the climate system that are more interacting. We have produced a set of increasingly coupled simulations with NEMO, CICE and WW3, exchanging more and more variables. The configuration is global at 1 degree resolution. The focus is on wave attenuation in sea ice and the impact of using modelled wave height for ocean mixing due to breaking waves. The example simulations give an idea of the possible impact on the simulated state versus the still considerable computational cost.</p>

KuKa altimeter mode data gathered during MOSAiC: scattering from snow covered sea ice and snow depth determination using dual-frequency and polarimetric approaches

2021 ◽  
Author(s):  
Rosemary Willatt ◽  
Julienne Stroeve ◽  
Vishnu Nandan ◽  
Rasmus Tonboe ◽  
Stefan Hendricks ◽  
...  
Keyword(s):  
Sea Ice ◽  
Snow Depth ◽  
Satellite Altimetry ◽  
Field Measurements ◽  
Dual Band ◽  
Altimetry Data ◽  
Dual Frequency ◽  
Sea Ice Thickness ◽  
Ka Band ◽  
Snow And Ice

<p>Retrieving the thickness of sea ice, and its snow cover, on long time- and length-scales is critical for studying climate. Satellite altimetry has provided estimations of sea ice thickness spanning nearly three decades, and more recently altimetry techniques have provided estimations of snow depth, using dual-band satellite altimetry data. These approaches are based on assumptions about the main scattering surfaces of the radiation. The dominant scattering surface is often assumed to be the snow/ice interface at Ku-band frequencies and the air/snow interface at Ka-band and laser frequencies. It has previously been shown that these assumptions do not always hold, but field data to investigate the dominant scattering surfaces and investigate how these relate to the physical snow and ice characteristics were spatially and temporally limited. The MOSAiC expedition provided a unique opportunity to gather data using a newly-developed Ku- and Ka-band radar 'KuKa' deployed over snow-covered sea ice, along with coincident field measurements of snow and ice properties. We present transect data gathered with the instrument looking at nadir to demonstrate how the scattering characteristics vary spatially and temporally in the Ku- and Ka-bands, and discuss implications for interpretation of dual-frequency satellite radar altimetry data. We compare KuKa data with field measurements to demonstrate snow depth retrieval using Ku- and Ka-band data.</p>

scholarly journals Pancake sea ice kinematics and dynamics using shipboard stereo video

2019 ◽  
Vol 61 (82) ◽  
pp. 1-11 ◽  
Author(s):  
Madison Smith ◽  
Jim Thomson
Keyword(s):  
Sea Ice ◽  
Energy Loss ◽  
Wave Energy ◽  
Wave Attenuation ◽  
Bulk Wave ◽  
Ocean Turbulence ◽  
Stereo Video ◽  
Ice Floes ◽  
Turbulence Generation

AbstractIn the marginal ice zone, surface waves drive motion of sea ice floes. The motion of floes relative to each other can cause periodic collisions, and drives the formation of pancake sea ice. Additionally, the motion of floes relative to the water results in turbulence generation at the interface between the ice and ocean below. These are important processes for the formation and growth of pancakes, and likely contribute to wave energy loss. Models and laboratory studies have been used to describe these motions, but there have been no in situ observations of relative ice velocities in a natural wave field. Here, we use shipboard stereo video to measure wave motion and relative motion of pancake floes simultaneously. The relative velocities of pancake floes are typically small compared to wave orbital motion (i.e. floes mostly follow the wave orbits). We find that relative velocities are well-captured by existing phase-resolved models, and are only somewhat over-estimated by using bulk wave parameters. Under the conditions observed, estimates of wave energy loss from ice–ocean turbulence are much larger than from pancake collisions. Increased relative pancake floe velocities in steeper wave fields may then result in more wave attenuation by increasing ice–ocean shear.

Laboratory and field measurements of acoustic scattering from sea ice

1988 ◽  
Vol 84 (S1) ◽  
pp. S123-S123
Author(s):  
K. C. Jezek ◽  
T. K. Stanton ◽  
A. J. Gow ◽  
M. Lange
Keyword(s):  
Sea Ice ◽  
Acoustic Scattering ◽  
Field Measurements
Sign in / Sign up

Export Citation Format

Share Document