scholarly journals Sea-ice dynamics in the Weddell Sea in winter

1991 ◽  
Vol 15 ◽  
pp. 9-16 ◽  
Author(s):  
Heinrich Hoeber
Keyword(s):  
Sea Ice ◽  
Bulk Viscosity ◽  
Current Data ◽  
Weddell Sea ◽  
Small Scale ◽  
Ice Dynamics ◽  
Sea Ice Dynamics ◽  
Momentum Budget ◽  
Ice Drift

Observations of ice drift received from an array of ARGOS buoys drifting in the Weddell Sea in winter 1986 are described. Wind and current data are also available, permitting derivation of the complete momentum budget including the internal ice stress computed as residuum. It is shown that the variability of forcing both of the atmosphere and of the ocean is large, and that internal ice stress is not negligible; monthly vector averages amount to about half of the wind and water stresses. Coefficients of shear and bulk viscosity are derived according to Hibler's model of ice rheology; they turn out to be negative occasionally, in particular when small-scale forcing of the atmosphere is large.

scholarly journals Sea-ice dynamics in the Weddell Sea in winter

1991 ◽  
Vol 15 ◽  
pp. 9-16 ◽  
Author(s):  
Heinrich Hoeber
Keyword(s):  
Sea Ice ◽  
Bulk Viscosity ◽  
Current Data ◽  
Weddell Sea ◽  
Small Scale ◽  
Ice Dynamics ◽  
Sea Ice Dynamics ◽  
Momentum Budget ◽  
Ice Drift

Observations of ice drift received from an array of ARGOS buoys drifting in the Weddell Sea in winter 1986 are described. Wind and current data are also available, permitting derivation of the complete momentum budget including the internal ice stress computed as residuum. It is shown that the variability of forcing both of the atmosphere and of the ocean is large, and that internal ice stress is not negligible; monthly vector averages amount to about half of the wind and water stresses. Coefficients of shear and bulk viscosity are derived according to Hibler's model of ice rheology; they turn out to be negative occasionally, in particular when small-scale forcing of the atmosphere is large.

scholarly journals Estimating instantaneous sea-ice dynamics from space using the bi-static radar measurements of Earth Explorer 10 candidate Harmony

2021 ◽  
Vol 15 (7) ◽  
pp. 3101-3118
Author(s):  
Marcel Kleinherenbrink ◽  
Anton Korosov ◽  
Thomas Newman ◽  
Andreas Theodosiou ◽  
Alexander S. Komarov ◽  
...  
Keyword(s):  
Sea Ice ◽  
High Temporal Resolution ◽  
Wave Spectra ◽  
Two Dimensional ◽  
Ice Dynamics ◽  
Sea Ice Dynamics ◽  
Ice Drift ◽  
Sea Ice Drift ◽  
Radar Measurements ◽  
Cross Track

Abstract. This article describes the observation techniques and suggests processing methods to estimate dynamical sea-ice parameters from data of the Earth Explorer 10 candidate Harmony. The two Harmony satellites will fly in a reconfigurable formation with Sentinel-1D. Both will be equipped with a multi-angle thermal infrared sensor and a passive radar receiver, which receives the reflected Sentinel-1D signals using two antennas. During the lifetime of the mission, two different formations will be flown. In the stereo formation, the Harmony satellites will fly approximately 300 km in front and behind Sentinel-1, which allows for the estimation of instantaneous sea-ice drift vectors. We demonstrate that the addition of instantaneous sea-ice drift estimates on top of the daily integrated values from feature tracking have benefits in terms of interpretation, sampling and resolution. The wide-swath instantaneous drift observations of Harmony also help to put high-temporal-resolution instantaneous buoy observations into a spatial context. Additionally, it allows for the extraction of deformation parameters, such as shear and divergence. As a result, Harmony's data will help to improve sea-ice statistics and parametrizations to constrain sea-ice models. In the cross-track interferometry (XTI) mode, Harmony's satellites will fly in close formation with an XTI baseline to be able to estimate surface elevations. This will allow for improved estimates of sea-ice volume and also enables the retrieval of full, two-dimensional swell-wave spectra in sea-ice-covered regions without any gaps. In stereo formation, the line-of-sight diversity allows the inference of swell properties in both directions using traditional velocity bunching approaches. In XTI mode, Harmony's phase differences are only sensitive to the ground-range direction swell. To fully recover two-dimensional swell-wave spectra, a synergy between XTI height spectra and intensity spectra is required. If selected, the Harmony mission will be launched in 2028.

A new coupled model to shed light on sea-ice--ocean interactions

2021 ◽  
Author(s):  
Guillaume Boutin ◽  
Einar Ólason ◽  
Pierre Rampal ◽  
Camille Lique ◽  
Claude Talandier ◽  
...  
Keyword(s):  
Sea Ice ◽  
Numerical Models ◽  
Coupled Model ◽  
Small Scale ◽  
Polar Regions ◽  
Fine Scale ◽  
Ice Dynamics ◽  
Damage Propagation ◽  
Sea Ice Dynamics ◽  
The Impact

<p>Sea ice is a key component of the earth’s climate system as it modulates air-sea interactions in polar regions. These interactions strongly depend on openings in the sea ice cover, which are associated with fine-scale sea ice deformations. Visco-plastic sea ice rheologies used in most numerical models struggle at representing these fine-scale sea ice dynamics without going to very costly horizontal resolutions (~1km). A solution is to use damage propagation sea ice models, which were shown to reproduce well sea ice deformations with little dependency on the mesh resolution. </p><p>Here we present results from the first ocean--sea-ice coupled model using a rheology with damage propagation. The ocean component is the NEMO-OPA model. The sea ice component is neXtSIM, introducing the newly developed Brittle Bingham-Maxwell rheology. Results show that sea ice dynamics are very well represented from large scales (sea ice drift) to small-scales (sea ice deformation). Sea ice properties relevant for climate, i.e volume and area, also show a remarkable match with satellite observations. This coupled framework opens new opportunities to quantify the impact of small-scale sea ice dynamics on ice-ocean interactions.</p>

scholarly journals On sea-ice dynamical regimes in the Arctic Ocean

2015 ◽  
Vol 56 (69) ◽  
pp. 323-331 ◽  
Author(s):  
J.V. Lukovich ◽  
J.K. Hutchings ◽  
D.G. Barber
Keyword(s):  
Sea Ice ◽  
Scaling Laws ◽  
High Arctic ◽  
The Arctic ◽  
Ice Dynamics ◽  
Scaling Properties ◽  
Sea Ice Dynamics ◽  
Ice Drift ◽  
Dynamical Regimes ◽  
Sea Ice Drift

AbstractCentral to an understanding of evolution in sea-ice characteristics in response to climate change is an understanding of sea-ice dynamics. In this study, we investigate regional differences in ice dynamics in the Beaufort Sea and High Arctic using high-frequency ice buoy (beacon) data deployed during the SEDNA and IPY-CFL field campaigns from spring 2007 to winter 2008. Examined in particular are scaling laws determined from absolute dispersion statistics. We create temporal scaling maps to determine whether distinct dynamical regimes can be identified with differing scaling properties. The results from this analysis provide an alternative characterization to changes in sea ice based on dynamics rather than concentration and thickness, and thus insight into, and improved understanding of, the connections between sea-ice drift and morphology.

Simulation of Sea Ice Dynamics During AIDJEX

1977 ◽  
Vol 99 (3) ◽  
pp. 491-497 ◽  
Author(s):  
R. S. Pritchard ◽  
M. D. Coon ◽  
M. G. McPhee
Keyword(s):  
Boundary Layer ◽  
Sea Ice ◽  
The Arctic ◽  
Ice Dynamics ◽  
Ice Surface ◽  
Sea Ice Dynamics ◽  
Pack Ice ◽  
Ice Drift ◽  
Ice Conditions ◽  
Arctic Ice

A mathematical model is used to simulate sea ice conditions observed during May 15–25, 1975 as part of the Arctic Ice Dynamics Joint Experiment. Calculated motions and forces within the region are compared with observed values. Ice velocity and tractions exerted on the upper and lower ice surface compare well with observed values. Results of another calculation using different boundary layer parameters help assess the effect of boundary layer models on the computed ice drift. The calculated strain field does not compare with observed strains well enough to allow prediction of stress in the pack ice. Several sources of error have been identified for future study.

scholarly journals On simulating high-frequency variability in Antarctic sea-ice dynamics models

1998 ◽  
Vol 27 ◽  
pp. 443-448 ◽  
Author(s):  
W. D. Hibler III ◽  
Petra Heil ◽  
Victoria I. Lytle
Keyword(s):  
Boundary Layer ◽  
Sea Ice ◽  
High Frequency ◽  
Ice Dynamics ◽  
Antarctic Sea Ice ◽  
Sea Ice Dynamics ◽  
Ice Drift ◽  
Dynamics Models ◽  
The Antarctic ◽  
Ocean Boundary

Due to frequent and intense storm systems moving across the Antarctic sea ice, ice drift and deformation fluctuate substantially. Observations of drilling buoys show inertial power to be a substantial component of ice drift and deformation. Because the inertial period at high latitudes is close to tidal periods, this peak can be amplified due to resonance. in practice, the energy dissipation by ice interaction plays a significant role in dampening out this inertial energy. in present sea-ice dynamics models both with and without ice interaction, this inertial motion is overdamped due to the underestimation of coupling to the ocean boundary layer. To develop a more consistent treatment of ice drift under fluctuating wind fields, we consider here a vertically integrated formulation of the ice-ocean boundary-layer system that incorporates a more realistic treatment of the upper ocean. Under steady wind conditions this model reduces to the normal water-drag formulation used in most sea-ice dynamics models. Simulations using this “imbedded” model are analyzed to elucidate the role of ice interaction in the Antarctic ice-pack in modifying the high-frequency motion and inducing deformation which in turn significantly impact ice-thickness characteristics. The simulations demonstrate that in an interacting ice field in the presence of kinematic waves inertial imbedding can lead to oscillations in ice concentration of up to ~10% open water. These variations are similar in magnitude to observed deformation fluctuations in tide-free regions.

scholarly journals Estimating instantaneous sea-ice dynamics from space using the bi-static radar measurements of Earth Explorer 10 candidate Harmony

2020 ◽  
Author(s):  
Marcel Kleinherenbrink ◽  
Anton Korosov ◽  
Thomas Newman ◽  
Andreas Theodosiou ◽  
Yuanhao Li ◽  
...  
Keyword(s):  
Sea Ice ◽  
Wave Spectra ◽  
Two Dimensional ◽  
Ice Dynamics ◽  
Sea Ice Dynamics ◽  
Ice Drift ◽  
Sea Ice Drift ◽  
Radar Measurements ◽  
Cross Track ◽  
First Time

Abstract. This article describes the observation techniques and processing methods to estimate dynamical sea-ice parameters from data of the Earth Explorer 10 candidate Harmony. The two Harmony satellites will fly in a reconfigurable formation with Sentinel-1D. Both will be equipped with a multi-angle thermal infra-red sensor and a passive radar receiver, which receive the reflected Sentinel-1D signals using two antennas. During the lifetime of the mission, two different formations will be flown. In the stereo formation, the Harmony satellites will fly approximately 300 km in front and behind Sentinel-1, which allows the estimation of instantaneous sea-ice drift vectors. We demonstrate that the addition of instantaneous sea-ice drift estimates on top of the daily integrated values from speckle tracking have benefits in terms of interpretation, sampling and resolution. Additionally, it allows for the extraction of deformation parameters, such as shear and divergence. As a result, Harmony's data will help improve sea-ice statistics and parametrizations to constrain sea-ice models. In the cross-track interferometry (XTI) mode, Harmony's satellites will fly in close formation with an XTI baseline to be able to estimate surface elevations. This will allow for improved estimates of sea-ice volume, and also enable for the first time to retrieve full two-dimensional swell-wave spectra in sea-ice covered regions without any gap. In stereo formation, the line-of-sight diversity allows to get swell in both directions using traditional velocity bunching approaches. In XTI mode, Harmony's phase differences are only sensitive to the ground-range direction swell. To fully recover two-dimensional swell-wave spectra, a synergy between XTI height spectra and intensity spectra is required. If selected, the Harmony mission will be launched in 2028.

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