scholarly journals Virtual radar ice buoys – a method for measuring fine-scale sea ice drift

2016 ◽  
Vol 10 (1) ◽  
pp. 29-42 ◽  
Author(s):  
J. Karvonen
Keyword(s):  
Sea Ice ◽  
Dynamic Properties ◽  
Weather Conditions ◽  
Radar Data ◽  
Optical Flow Method ◽  
Drift Estimation ◽  
Ice Drift ◽  
Sea Ice Drift ◽  
Ice Field ◽  
Direction Information

Abstract. Here we present an algorithm for continuous ice drift estimation based on coastal and ship radar data. The ice drift is estimated for automatically selected ice targets in the images. These targets are here called virtual buoys (VBs) and are tracked based on an optical flow method. To maintain continuous ice drift tracking new VBs are added after a given number of VBs have been lost; i.e. they can not be tracked reliably any more. Here we also apply the algorithm to data of three test cases to demonstrate its capabilities and properties. Two of these cases use coastal radar data and one ship radar data. Ice drift velocity and direction information derived from the VB motion are computed and compared to the prevailing ice and weather conditions. Also a quantity measuring the local divergence or convergence is computed for some VBs to demonstrate the capability to estimate derived kinematic sea ice parameters from VB location time series. The results produced by the algorithm can be used as an input for estimation of the dynamic properties of sea the ice field, such as ice divergence or convergence, shear, vorticity, and total deformation.

scholarly journals Virtual radar ice buoys – a method for measuring fine-scale dynamic properties of sea ice

2015 ◽  
Vol 9 (5) ◽  
pp. 4701-4731 ◽  
Author(s):  
J. Karvonen
Keyword(s):  
Sea Ice ◽  
Optical Flow ◽  
Dynamic Properties ◽  
Radar Data ◽  
Test Cases ◽  
Fine Scale ◽  
Ice Dynamics ◽  
Flow Method ◽  
Optical Flow Method ◽  
Ice Drift

Abstract. Here we present an algorithm for continuous ice dynamics estimation based on coastal and ship radar data. The ice dynamics are estimated based on automatically selected ice targets in the images. These targets are here called virtual buoys (VB's) and are tracked based on an optical flow method. To maintain continuous ice drift tracking new VB's are added after a~given number of VB's have been lost i.e. they can not be tracked reliably any more. Some tracking results and some computed derived quantities for a~few test cases are presented.

scholarly journals An Antarctic field study of the rheology and movement of a sea-ice floe aggregate

1991 ◽  
Vol 15 ◽  
pp. 261-264
Author(s):  
T.H. Jacka ◽  
R. Thwaites ◽  
J.C Wilson
Keyword(s):  
Wind Speed ◽  
Sea Ice ◽  
Drift Rate ◽  
Small Strain ◽  
Local Conditions ◽  
Scientific Investigations ◽  
Ice Drift ◽  
Sea Ice Drift ◽  
Ice Field ◽  
Meteorological Observations

M.V. Nella Dan was beset in ice near 66°S, 51°Ε from 27 October to 15 December 1985. The scientific investigations planned for the voyage into the sea-ice zone included ice thickness, concentration and extent measurements, aerial photography of the ice, a core drilling project and meteorological observations. Once beset, the programme was expanded to include repeat measurements of a small strain grid and measurements of the sea-ice drift rate. Strongly convergent local conditions had led to the initial besetment of the ship. Analysis of measurements of the strain grid area over an 11 d period shows that, although there is some indication that the ice field may have been divergent, opening by approximately 3.4% over this period, there are large errors in the measurements and some doubt must be placed on the reliability of this estimate. The drift speed and direction were found to be highly dependent on wind speed and direction, the drift rate being approximately 2.7% of the wind speed at an angle of about 29° to the left of the wind direction.

scholarly journals An Antarctic field study of the rheology and movement of a sea-ice floe aggregate

1991 ◽  
Vol 15 ◽  
pp. 261-264
Author(s):  
T.H. Jacka ◽  
R. Thwaites ◽  
J.C Wilson
Keyword(s):  
Wind Speed ◽  
Sea Ice ◽  
Drift Rate ◽  
Small Strain ◽  
Local Conditions ◽  
Scientific Investigations ◽  
Ice Drift ◽  
Sea Ice Drift ◽  
Ice Field ◽  
Meteorological Observations

M.V.Nella Danwas beset in ice near 66°S, 51°Ε from 27 October to 15 December 1985. The scientific investigations planned for the voyage into the sea-ice zone included ice thickness, concentration and extent measurements, aerial photography of the ice, a core drilling project and meteorological observations. Once beset, the programme was expanded to include repeat measurements of a small strain grid and measurements of the sea-ice drift rate. Strongly convergent local conditions had led to the initial besetment of the ship. Analysis of measurements of the strain grid area over an 11 d period shows that, although there is some indication that the ice field may have been divergent, opening by approximately 3.4% over this period, there are large errors in the measurements and some doubt must be placed on the reliability of this estimate. The drift speed and direction were found to be highly dependent on wind speed and direction, the drift rate being approximately 2.7% of the wind speed at an angle of about 29° to the left of the wind direction.

scholarly journals Improving Multiyear Sea Ice Concentration Estimates with Sea Ice Drift

2016 ◽  
Vol 8 (5) ◽  
pp. 397 ◽  
Author(s):  
Yufang Ye ◽  
Mohammed Shokr ◽  
Georg Heygster ◽  
Gunnar Spreen
Keyword(s):  
Sea Ice ◽  
Sea Ice Concentration ◽  
Ice Drift ◽  
Ice Concentration ◽  
Sea Ice Drift

Oceanic eddy signature on SAR-derived sea ice drift and vorticity

2021 ◽  
Author(s):  
Angelina Cassianides ◽  
Camillie Lique ◽  
Anton Korosov
Keyword(s):  
Sea Ice ◽  
Surface Current ◽  
Satellite Observation ◽  
The Arctic ◽  
Global Ocean ◽  
Sar Images ◽  
Surface Ocean ◽  
Ice Drift ◽  
Sea Ice Drift ◽  
Oceanic Eddy

<p>In the global ocean, mesoscale eddies are routinely observed from satellite observation. In the Arctic Ocean, however, their observation is impeded by the presence of sea ice, although there is a growing recognition that eddy may be important for the evolution of the sea ice cover. In this talk, we will present a new method of surface ocean eddy detection based on their signature in sea ice vorticity retrieved from Synthetic Aperture Radar (SAR) images. A combination of Feature Tracking and Pattern Matching algorithm is used to compute the sea ice drift from pairs of SAR images. We will mostly focus on the case of one eddy in October 2017 in the marginal ice zone of the Canadian Basin, which was sampled by mooring observations, allowing a detailed description of its characteristics. Although the eddy could not be identified by visual inspection of the SAR images, its signature is revealed as a dipole anomaly in sea ice vorticity, which suggests that the eddy is a dipole composed of a cyclone and an anticyclone, with a horizontal scale of 80-100 km and persisted over a week. We will also discuss the relative contributions of the wind and the surface current to the sea ice vorticity. We anticipate that the robustness of our method will allow us to detect more eddies as more SAR observations become available in the future.</p>

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